Dynamo Lighting for Motor Cars

DYNAMO L IG HTING

FOR MOTOR CARS

M.

.

A. CODD

SE C O N D E D I T I O N

140 IL L USTRATIONS

I oubou

E. F . N. SPON L TD., 57 HAYMARKET

new 190th

SPON CHAMBERL AIN , 1 23 L IBERTY STREET

1 9 1 4

C ONT ENTS

CHAP.

I . INTRODUCTION AND GENERAL PRI NC IPLESThe Dynamo—Choice of Machine—The AccumulatorsL amps

—Bulbs. o

I I . FITTI NG THE SYSTEMG enera l Considerations—Position—D riving—G earing

—Drive from the Fan Pulley—From the Flywheel—Fromthe Clutchshaft—Beh ind the G ear Box .

I I I . WIR ING THE CAR

Wiring up—Single- InsulatedSystem—Doub le- InsulatedReturn System

—D ifficulties in Obta ining Constant Output-The Cut-Oute —Electrica l Cut-Outs—~Free Wheel Cut

Out—Mechanica l Cut-Outs.

IV . PERMANENT MAGNET SYSTEMThe M ira Magnetolite.

V . PERMANENT AND ELECTRO-MAGNET SYSTEMDucellier Dynamo .

VI . ELECTRO -MAGNETICALLY GOVERNED SYSTEMThe Perfect The C.A.V . Dynamo The Brolt

Dynamo—The Leitner Dynamo .

VI I . EL ECTRo -MAGNETICALLY CONTROLLED SYSTEMMagician Dynamo—Bleriot System—Polkey -"arrott

Dynamo—Facile Dynamo—The Bosch Dynamo—TheEisemann Dynamo—The Pape D ynamo .

3 4521 3

v i CONTENTS

CHAP.

VI I I . MECHANICALLY-CONTROLLED SYSTEML ucas Dynamo m Peto and Radford Dynamo— The

E.B.C. Dynamo .

IX. HOT W IRE CONTROLLED SYSTEMSL ithanode D ynamo—Rushmore Dynamo .

X . SOME USEFUL ACCESSORI ESSteering Col umn Lamp—Scuttle Dash Lamp— Interior

L ighting L amp—Cape Cart H ood Lamp—Cigar L ightersElectric H orns—Wiring of Interior Lamps.

R I U PKEEP, MAINTENANCE , AND LOCATION OF FAUL-TS

Bearings—Commutator Contacts Batteries—\V iringSw itchboards—Searching for Faults— G enera l Instruc

tions.

INDEX

99

DYNAMO L IG HTIN G

FOR MOTOR CARS

CHAPTER I

INTRODUCTION AND GENERAL PRINCIP L ES

WE do not propose to enter i n to a techn ical descript ion Of the various workings Of the dynamo l igh t ingsys tems hereafter described

,rather confin ing ourselves

to the broad ou tl i ne Of thei r various features,and

ind icat i ng the main po ints where in the various sys temsd iffer

,i n the hOpe Of enabl ing the reader to bring an

in tel l igen t working knowledge to bear on the mach inewi th wh ich he has to do .

Elec tr i c l ight ing sys tems may be compared forpract ical purposes to a wa ter pumping plan t

,and may

be d iv ided in to four separate parts : I . The dynamo ,

which raises the pressure Of electric i ty to the righ tvol tage

,as the pump raises the pressure Of water to

the necessary “head . 2 . The accumulator or s toragebattery , which stores the elec tr ic i ty s im i larly as thetank or reservoi r s tores the water pumped up . 3 . The

electric lamps or bulbs , which use up the stored electrica l energy much as a water mo tor or foun tain u sesi t and 4 . The wi ring and swi tches

,correspond ing to

the piping and taps of a hydraul i c sys tem .

LT.

The Dynam0 .—Cons idering firs tly the dynamo .

This cons i sts of five essent ial parts : (a ) the armature ,a rotat i ng cyl i ndrical magnet wound round with wi rein which the current i s genera ted (é) the commutator,which is su i tably connected to the armature windingsand rotates wi th them (c) the brushes , which press onthe commutator and col lect the curren t from i t

,pass ing

i t out to the necessary wires of the sys tem ; the fieldmagnet

,which may be e i ther a permanent or an

electro -magnet or a combinat ion of both,i ts funct ion

be ing to give a strong magnet ic field for the armature to rotate i n ; (e) the bearings and other purelymechan ical detai ls of the mach ine .

It shoul d be remembered that the output of themachine depends : ( I ) roughly on the strength of thefield ; (2 ) on the speed wi th which the armature rotates ;and (3 ) on the number of turns of wi re upon thearmature

,al though there are o ther factors which l im i t

the output,such as heat ing

,dimens ions , and effic iency .

Choice of Machine — In choos ing a dynamo i ti s wel l to ascertain beyond the usual facts of des ign ,

output,and weigh t that the bearings and commutator

are generously proport ioned,as these are the two

weak points of l ight ing dynamos owing to the restri ctedspace a t the disposal of the des igner . A mach ineshould also be chosen in preference which gives i tsmaximum work ing output at a low speed , and also thespeed wh ich the dynamo “cuts in , or begins togenerate effec t ively

,should rece ive atten t ion .

The Accumulators.—These are general ly the

same descript ion of cel l used for ign i t ion work oncars , but they must be of a suffi c ien t ly large s ize andvery robust to take the heavy currents generated bythe dynamo . It i s best to employ the cel ls suppl iedby the maker , as this gives more sat isfac t ion both to

INTRODUCTION AND GENERAL PRINCIPLES 3

the manufacturer who knows the bat tery is righ t , andto the user who can fal l back on the maker in theeven t of the cel l s fai l ing; A common error i n therat ing ofb atteries may be no ted here . Bat teries forign i t ion purposes are rated in Ign i t ion ampere hourswhich are real ly double the real capaci ty in l igh t i nghours . Thus a ba t tery rated at 80 ign i t ion amperehours has only a capaci ty of 40 ampere hours forl ight i ng ,

and a cel l of 30 ampere hours would g ive anign i t ion ra t ing of 60 ign i t i on ampere hours , a barbaroussurv ival of the bad old days .

It wil l be understood that 40 ampere hours meansa discharge of one ampere for forty hours and twoamperes for 20 hours , and so on , whatever the vol tageof the cel l or batteries , be i t 4 ,

6 , 8 , or 1 2 volts .

It should be no ted that the effic iency of a bat terydecreases i f a large curren t be taken ; thus i n the40

- ampere hour cel l under not i ce,i f 5 amperes were

taken i t would not give e ight hours ’ l ight as i t theoretical ly should

,bu t probably ra ther less than seven

,as 5

amperes i s rather too large a curren t to take from aba ttery of that s i ze for long .

The discharge ra te i s general ly s tated on the s ideof the cel l by the makers , bu t a safe rule i s to al low ad ischarge of one - tenth the ful l capaci ty in amperehours thus a 50 - ampere hour cel l could be dischargedsafely a t 5 amperes .

Th is rate can be exceeded for short periods but ata cons iderable loss of effic iency .

We shal l not en ter i nto detai l s for main tenance ofaccumulators , as the general rules that apply to ign i t ioncel l s apply equal ly wel l to l igh t ing batteries . The

ch ief points to remember are1 . Do not l eave the cel ls d ischarged .

2 . Keep the cel l s fi l l ed wi th acid wel l over theplates .

4 DYNAMO LIGHTING FOR MOTOR CARS

3 . Vasel ine the term inals and keep the tops of thecell s clean to avoid leakage .

4 . Pack the cel ls t igh tl y i n the i r case to avo idjol t ing and v ibra t ion .

Exam ine the cel ls occas ional ly ; because they areh idden away in a box don ’t neglect them —the batteryand the tyres are general ly the two worst - treatedaccessories on the car .

L amps.

-By lamps we mean the projectors i ncon trad ist inct ion to the “ bulbs .

”

The essent ial poin ts of a lamp are that i t shouldgive l ight

,a detai l that some manufacturers appear to

overlook,and th is l ight - g iv ing property depends solely

upon the shape Of the refl ector . Every maker has h i sown idea of the curve or shape of the reflector , whichshould be a parabola or some derivat ion of i t . The

only real test is an actual road trial , photometricaltests be ing pract ical ly useless . The l ight should beproj ec ted well ahead

,so as to p ick out cycl ists and

unl ighted carts , etc . : any i l lum inant , even a naphthaflare

,wil l l ight up the immed iate ne ighbourhood of

the car,and with the adven t of tarred roads and

fast n ight driv ing the searchl ight type of reflector i sessent ial .

Referr ing to the use of coloured reflectors,i n fog

the i r ut i l i ty does not seem proved , and al l owing for

the smal l number of t imes they are requ i red duringthe year thei r employment hardly seems worth whilein any case

,the use of amber- coloured bulbs seems to

en ti rely solve the d ifficul ty .

Secondary , cons iderat ions for lamps are that theyShould be wa ter and dus t t ight

,tha t the head lamps

at l east should have focuss ing arrangements,they

should be of pleas ing contour and devo id of superfluousproject ions rendering them difficul t to clean .

INTRODUCTION AND GENERAL PRINCIPLES 5

L amps of the freak type necess i tat i ng special bulbsshould no t be purchased .

Bulbs.

— The wonderful improvement effected inthe me tal fi lamen t lamp has made the elec tr i c l igh t i ngof cars poss ible

,but there are certa in detai ls i n the

choice of bulbs wh ich should be no ted . The brasscap should be large enough to hold the bulb mechani

cal ly through the medium of the plaster fi l l i ng , andthe contacts should be capable of carry ing the curren tadequately . The fi lamen t should be of the right shapefor the part icular reflecto r i n wh ich i t i s to be used , andshould be in the righ t focal centre ( this i s general lylocated wel l back in the bulb ) and las tly the glass bulbshould preferably be pipless i n fron t and mus t be of

a suffi c ien t d iameter and area to d iss ipate the hea tgenerated by the fi lament , and be large enough to

main tain i ts vacuum and to receive the occluded gasesfrom the fi lamen t wi thout loweri ng the vacuum to anymarked extent .

Smal l bayonet holders should be used in preferenceto large as the lat ter cut away a large port ion of themos t useful part of the reflector .

The earl ier tungs ten lamps had bri ttle fi laments,

which were fragi le , and could not sat i sfac tori ly bewound in the concentrated or focuss ing form requ i redfor mo tor - car headl ights . A subsequent developmen t

,

known as the drawn -wire process,has made i t pos

s ibl e to produce a duct i l e tungsten fi lamen t of greats trength , which i s suffi c iently flexibl e to be wound inany des i red form (Fig .

Perhaps one of the greates t advan tages of therecen t types of automobi le elec tri c lamps is the facttha t they can be effect ively used in reflectors des ignedon theore t i cal ly correc t l i nes . In the case of gas lamps

,

cons iderat ions of ven t i lat ion , cleanl iness , and tempera


ture en ter in to the des ign of the reflector un i ts— and

these cons idera t ions are general ly a t variance with theeffic ien t reflect ion and distr ibu t ion of the l ight .

For pract i cal purposes i t may be said that the

Fig . I .Headlight Lamp (Hel ica l Coil Filament) .

headl igh t lamps,i n which the fi lamen t l s concen

trated i n to the smalles t poss ibl e space , win conj unct ion wi th a parabol i c reflec tor , prov ide asuffic iently close approximat ion to the theoret i calideaL

CHAPTER II

FITTING THE SYSTEM

F itting the Dynamo — Owing to the fac t that a tthe presen t date many car manufac turers do no tprov ide su i tabl e provis ion for fi tt ing the dynamo ,

various pos i t ions have to be Chosen,each of which

has some advantage or d isadvan tage . We proposeto take the various poss ible pos i t ions i n order .

G enera l Consz°

dem l z°

ons.

— l n fi tt i ng the dynamo ,

a firm,preferably non - magnet ic

,base should be chosen

in a clean and dry pos i t ion . Care should be takenno t to fi t too near the exhaus t pipe . The dynamo

,

i f fi tted on the Chass is frame,should be wel l s tayed

to preven t v ibra t ion . The mach ine should not bedr iven from the tw o to one gear i f i t can poss iblybe avoided .

Posz

'

tz'

orz .

— There are two main pos i t ions in fi tt ingthe dynamo which requi re cons idera t ion— the dynamocan be fi tted before o r beh ind the gear box (F ig .

If the dynamo be fi tted be fore the gear box , tha t i s tothe engine

,fan

,flywheel

,or shaft be tween the flywheel

and gear box , the variat ions Of speed wi l l be h igh andh igh rates o f speed wil l be me t wi th , e.g .

,when the

engine is accelerated for h i l l cl imbing on fi rs t or secondgear ; and consequen tly the wear and tear on thedynamo wil l be greater . A compensa t i ng advantage

,

however , wil l be that a higher mean rate of Chargingw i l l resul t , moreover, even when the car i s at res t , sayi n a traffic block

,the engine wil l s t i l l be turn ing and

the bat tery Charging .

8 DYNAMO L IGHTING FOR MOTOR CARS

When driv ing from beh ind the gear box thedynamo wil l natural ly only charge when the car i si n mot ion

,and therefore the periods of charging

wil l be in termittent as compared to a driveengine .

The drive that i s obtained , however , i s muchstead ie r and has a smal ler range of fluc tuat ion fromthe propel ler shaft than on the eng ine s ide when the

FITTING THE SYSTEM 9

engine is i n a lower gear,and therefore the wear and

tear on the dynamo is much less .

D r iving— The me thod of driv ing the dynamo

should be through a bel t,e i ther fla t or V (Fig . as

thi s runs much swee ter than a Chain o r gear dr ive ,and also gives a certai n amoun t of sl ip at h ighspeeds . In awkward pos i t i ons

,or where i t i s requi red

to s trike the dynamo off when runn ing , a fric t ion gearmay be employed driv ing through a flexible shaft(Fig . By varying the pressure of the frict ionrol le r upon the flywheel through a spring any sui tablemaximum outpu t may be arranged . The rol ler can

be wi thdrawn from contac t al toge ther by releas ing theSpring through a sui table Bowden wire .

Another me thod of accompl ish ing the same resul ti s through a spring loaded jockey - pul ley .

A l though many people inqui re i f the i r mach inesshould no t be able to be s truck ou t of ac t ion

,there is

no real need to do so , as the wear of the commutatorand bearings is so sl ight , and the power needed toturn the dynamo , even when loaded , so smal l , that thenecess i ty i s more sen t i men tal than real .

In fi tt ing, make qu i te sure tha t no water or di rtcan be thrown on the bel t , as these

,part i cularly water

,

shorten its l i fe very cons iderably .

1 0 DYNAMO LIGHTING FOR MOTOR CARS

Where there is not room to ge t a sat isfactorylength of bel t drive , a s i len t chain may be employed ,

but every effort should be made to employ a bel tdrive where poss ible .

When i nstal l ing the dynamo , cons iderat ion shouldbe given to two poin ts , whether the car i s h ighor low geared

,that is , whether geared for town or

country use , and secondly , whether the car is to beused during the day as wel l as at n igh t , or for n ightand theatre use only .

G ea r ing—Wi th regard to the ques t ion of gears

,

a low - geared car wi l l Obviously at tain i ts maximumengine speed at a lower rate of travel than that of

a normally or h igh geared car,such as an ord inary

touring car. It wil l i n th is case be necessary to

FITTING THE SYSTEM 1 1

gear the dynamo somewhat lower than for thecorresponding speed of a touring car wi th a lowerengine speed .

If the dynamo be too high geared i t wi l l cut i nat a low car speed

,bu t wi l l be rotat i ng ineffect ively

at m odera te and high car speeds,as i ts maximum

output po in t will have long s ince been passed .

On the other hand,i f the machine be too low

geared , i ts cutt ing - in speed wi l l rarely be reachedin town

,and the battery wi l l never be ful ly charged .

The above appl ies also to a country or touringcar in the oppos i te sense . A car wh ich is arrangedto cut in at 1 2 or 1 5 miles an hour, and give i tsmaximum outpu t at 20 or 25 miles , i f driven slowlyi n town wil l probably not reach the cu t t i ng- in speedat al l

,and therefore again the bat teries wi l l never

be fully charged .

Wi th regard to the second Cons iderat ion , fornormal day and n igh t runn ing

,the curren t s tored

during the day wi th the curren t given by the dynamoshould prove enough for the lamp consumption byn igh t , but for cars used only by n igh t , such as theatrecars , doctors ’ ca rs,

. and advert i s ing vans,the dynamo

mus t give enough outpu t to feed the lamps d irec twithout drawing on the bat tery a t al l , and care mustbe taken to ge t a suffic ien t ly large mach i ne to do so .

As the outpu t of many mach ines can be raisedat wi l l by gearing h igher or t ighten ing the sl ippingclutch , a l i ttl e t rial and error wi l l soon give the meannormal outpu t sui table for give and take condi t ionsbo th in town and country by day and by n igh t .

D r ive f rom fil e Fa n P u l ley (F igs . 5,—On the

whole this i s the most des i rabl e pos i t ion when therei s room under the bonnet

,as i t i s very access ible .

Where poss ible a triangular drive should be arranged,

that i s , the bel t should pass over the engine pul ley to


the fan,from the fan pul ley to the dynamo

,then

from the dynamo pulley back to the eng i ne . Thisprovides a long elas t i c l ength of bel t

,moreover

i t has the further (adven t i t ious) advantage that atvery h igh speeds the bel t wil l tend to sl ip

,thereby

sav ing undue wear and tear,even in those mach ines

fi tted wi th sl ipping clutch mechani sms .

F rom Me Fly w /zeeZ— G eneral ly speaking a drive

from the flywheel necess i tates such a large pul ley on

the dynamo to avoid excess ive speeds as to be out

SECONDARYPUL LEY

CRANKSHAFTPU L LEY

of the quest ion , though some form of fric t ion drivemay somet imes be used , either

‘

direct or through aflexible shaft

,or a smaller pul ley be fi tted concentric

w i th the flywheel and bol ted to the s ide (F igs . 7 ,

F ig . 7 8 ,p . 64 .

Fr om Me Clute/zskaft.

— This i s a very favouri tepos i t ion

,and on the whole very sat isfactory . It

has the disadvantages that when the Clutch is wi thdrawn , the dynamo Slows down ,

and that the motionof the clutchshaft throws the two pull eys momentari ly

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preferable,bu t i n mos t cases the shoes are outsIde ,

thus preven t i ng the fi tt ing of the bel t .If the pul ley is fi tted to the propel ler s aft It

Fig . 1 0 .

should be arranged a s close to the gear boxposs ible i n order to render the vert i cal movemen ts

Fig . 1 1 .

of the shaft caused by road inequal i t i es a s

poss ible . This pos i t ion has the great advan tage of

al lowing an ample length of bel t , as the dynamo can

F ITTING THE SYSTEM 1 5

be hung on a bracke t from the Chass is or screwed tothe s teps at the Side . Care mus t . however, be takento see that the s i l encer and torque rods

,e tc . , do no t

foul the bel t,and the bel t i tsel f Should be enclosed

from mud and water .

H av ing sat i sfactori ly moun ted the dynamo and i tsdrive , we wi l l nex t turn to the importan t ma tter of

wiring up .

CHAPTER III

WIRING THE CAR

W iring U p .

—NO part of the i nstal lat ion of a l igh t i ngset cal ls for more care and a tten t ion than the wir ingup

,and every precau t ion should be '

taken to do th isnot only i n the most thorough way bu t also to use thebes t materials .

Hal f the troubles met wi th in dynamo se ts arethrough careless fi tt i ng up and w iri ng .

There are two systems of wiring up , the s ingleinsulated and the doubl e - insulated re turn .

The smg /e- im u /a ted sy stem fol lows that un iversally

used in the ign i t ion system of the car and has thegreat advan tages of s impl ic i ty and avo idance of

dupl icat ion of W i r i ng . It can , moreover , be morereadi ly connected wi th ex is t ing 1gn1t10n apparatus .

If a faul t occurs wi th th is system of wiring i t i s veryeas i ly located .

The doué/e- irzsu /ated return sys tem is more general ly employed

,owing doubtless to the fact that mos t

lamp holders are made for th is system . It i s cla imedwhen a s ingle faul t occurs owing to the doubl e insulat ion that no damage wil l be done

,as the insulat ion of

the second conduc tor wil l st i l l preven t a short - c i rcu i t .

It should be noticed,however , that i n the even t of the

second conductor ’s i nsulat ion being pierced (and i t isquite l ikely that both would go together being underthe same s taple) the faul t i s much more difficult

‘

fito

find , particularly i f the two faul ts are in d ifferent partsof the wiring system . Again the bat tery has often to

WIRING THE CAR 1 7

be wi l ful ly earthed i n order to take advan tage of thehorn

,co i l

,or dual ign i t ion sys tem now fi t ted to mos t

cars,therefore a s ingle l eakage on the other con

ductor wil l bring about a short - c i rcu i t .As al ready sta ted , then ,

whe ther a s ingle or doublei nsulated return be used

,every care should be taken

to see that the best insulat ion i s employed and thatthe wiring is careful ly and neat ly fixed to the chass i sby cl ips or other sui table means . Wi res mus t not befes tooned around , as they are l iable to sway abou t andfray out or catch i n some moving part . The conductors should be ample to carry the current wi thou t

Fig . 1 2. F ig . 1 3 .

an undue vol tage drop and should preferably be e i therarmoured themselves or run in su i table flexible me tall i ctubing with fibre bushes a t the end o f each length topreven t chafing .

F ig . 1 2 shows a sui table plug or adap ter for theends of the wiring lead ing to lamps . It i s s imply abayone t socke t fitt ing in to one end of a double holder

,

the o ther end of the holder accommodat ing the lamps.

Where pin plugs are employed F ig . I 3 shows a su i table armoured connec t ion of me tal l ic tube with watert ight socke t for screwing to the Chass is . A screwedring holds the p in plug to the body of the fi t t ing toavoid the connect ions v ibrat i ng out of place .


The i l lust rat ion ,F ig . I 4 , shows the usual connec

t ions of a dynamo se t , that i s , the dynamo and lampsare i n paral lel wi th the accumulator which floats on

nsu

l

ate

System

.

the mains .

Thus if the lampsare on and the dynamoi s not Charging , thebat tery prov ides thewhole current ; i f thebattery is part ial lygenerat i ng , the curren tfor the lamps is suppl ied by the dynamoand accumulators to

gether . As the speedof the dynamo rises

,

i ts outpu t should soonequal that of the lampconsumpt ion

,a t which

stage no curren t wi l lenter or l eave thebat tery

,and final ly at

ful l output the dynamocurren t wil l supplythe lamps and storea surplus i n the ba ttery . If the lamps arenot on , the wholedynamo output wi l l bes tored in the cel lsthi s happens duringdayl ight runn ing .

It i s preferable to choose a dynamo whose outpu tat 20 miles an hour equals or exceeds the con ;

sumption of the lamps,o therwise one i s dependen t on

dayl ight Charging to make up the surplus curren t

WIRING THE CAR 1 9

requi red by the lamps , the d ifference be tween theful l dynamo ou tpu t and the lamp consump t ion has tobe drawn from the batteries wh ich mus t be Chargedby dayl igh t run

n ing,which is not

always avai lable .

In the diagram ,

Fig . 1 5,the nega

t ive wi re is Shownearthed o r u t i l i si ng the frame asre turn . Wi th theo rd i n a r y twowire o r doubleinsula ted wire system the negat ives ide instead of

being the framewil l s imply be an

o ther insulated w ires im ilar to the pos it ive s ide . In thiscase twin wire i susual ly used

,the

connec t ions be ingmade d i rec tly fromthe lamp or dynamo to the swi tchboard , and not wi ths ingle wi res asshown in the d iagram . Th is avoidsso l d e r e d j o i n t s .

The wiring , however, gives exact ly the same con

nections.

When wiring the car an excel len t method ofB 2


ascertain ing i f the tai l lamp is burn ing correc tly isto W i re th is lamp in series wi th ano ther s i tuated on

the dash or s teering column (F ig . If the tai llamp goes out

,tha t on the dash be ing in series w il l

natural ly go out as wel l . Th is method has theadvantage of s impl ic i ty over those us ing magne t i crelays to l ight up an ind icator lamp on the sw i tchboard ,

and further, no current is wasted in the magnet co i ls .

If the l ight of the dash lamp be obj ected to , i t i s an

DASH L AMPTA'L L AMP

To ACCUMULATORS on aunct ionBOX

Fig . 1 6 .

easy matter to obscure i t by gumming a small p iece of

t issue paper over the lens of the dash lamp ; th i s wi l lgive a d iffused l ight devo id of glare but enough torender obj ects on the dash , such as the speedometerand lubricators , qui te v is ible .

Difficulties in Ob ta ining Constant Output.

Wi th varying speed of a dynamo as usually constructedthe output also varies , thus the greater the speed thegreater the outpu t .

If th is were permi tted to occur unchecked on a



extens ively cop ied , i s to employ permanen t fieldmagnets wh ich have

,o f course

,a fixed s trength and.

give a good ou tpu t at low speeds . As the speed r isesthe arma ture (which is i tsel f, of course , a rotat ingmagnet) begins to grow stronger and exert a countermagne t i s ing effec t agains t the permanent field magne ts .

This i s known as armature react ion ,and when suffi c ien t

speed i s attained,the magne t i sm of the armature wi l l

counterac t that of the fields and a state of balance isset up

,the effec t being that no greater outpu t can be

ob tained .

This effec t i s also ob tained wi th wi re wound fieldsi n a somewhat s im ilar but more compl icated way byus ing what are cal l ed neu tral poles between the twomain poles

,so that as the speed of the armature

increases,the magnetism is shun ted back by the

neutral poles more and more,thus leav ing the armature

with i ts normal magnetis ing flow at any speed .

St i l l ano ther me thod i s to use four brushes , twomain and two auxi l iary .

The main brushes are connec ted wi th the two

auxil iary brushes,so that at low speeds they help to

strengthen the magne t i sm,while a t high speeds they

give curren t to the ou ter c i rcu it .

This me thod is very effic ient,bu t cal ls for ra ther

more compl icated connect ions than the usual two

brush method .

In ord inary ligh t ing prac t i ce many mach ines havewhat i s known as a compound wind ing

,that i s , i n

add i t ion to the ord inary shunt magnet is ing co il , themain current is al so made to pass round the magne tswi th a V iew to further s trengthen ing them as the loadincreases . In car dynamos th is property is made useof i n some cases

,bu t i n the i nverse sense

,i n that the

main current or ser i es coi l i s used to weaken the exis ti ng magne t i sm as the speed increases , thereby keeping

IVIRING THE CAR 23

down the tendency of the curren t to become exces

s ive .

It i s wel l known tha t certain me tals increase inres istance as thei r tempera ture r ises , and this propertyhas been used in one or tw o sys tems by putt inga leng th of i ron or n i ckel w i re i n series w i th the shun tco i ls

,the consequence be ing tha t as the curren t tends

to r i se the co i l of i ron wi re becomes hot, i ts temperature begins to rise

,and the curren t which would

normal ly flow to the shun t co i l i s choked back , therebyeffec t ing the necessary cu t t ing down of the curren t a tmaximum speeds .

These various sys tems w il l subsequen t ly be moreful ly described when explain ing the mach ines to whichthey are pecul iar .

It Should be unders tood that al though the variousdev ices described keep the ou tput of current wi thinreasonable bounds an accumulator i s necessary not

only to effect the final s teadying effect and to storeup the surplus energy not used by the lamps

,bu t

also to l igh t the car when i t i s a t res t or movingat such a slow speed as not to generate suffi c ien tenergy to l igh t the lamps .

The Cut-Out.

-When the car i s at res t thedynamo natural ly ceases to ro ta te

,and the bat tery

would under ord inary condi t ion s begin to d ischargebackward through i t i n the effort to drive i t as anelec tri c mo tor . To remedy th is d isadvantage recourseis had to an apparatus known as a cut - out . A s wi ththe maximum ou tpu t governor al ready described thesemay be d iv ided in to electrical or mechan ical cut - outs .

Electrical Cut-OutS.—The commonest type of

elec trical cu t- ou t, of w hich there are many variat ions ,Cons is ts of a magnet or soleno id wh ich i s energisedfrom the dynamo and which at trac ts a moving armature


against the act ion of a spring when the vol tage of thedynamo i s abou t equal to that of the accumulator ,thereby Clos ing the c i rcu i t and enabl ing the dynamoto charge the cel ls (Fig .

This type of apparatus has the d isadvantage of

being very del icate and easi ly derangeable i n the handsof the ord inary driver : the con tact su rfaces are l iableto give trouble

,as owing to the smal l power of the

magnets the contacts have to be rather l ight .

A certain amoun t of curren t is used ,too , by the

magne t coi l s,which under certain c i rcumstances are

l iable to burn ou t. It

ma i s claimed that the con

tacts only break at “ novol tage , bu t i n prac t i cethis rarely occurs .

Furthermore , whenthe dynamo is runn ingslowly and the lampsare on ,

the battery be ingrather run down

,there

i s a l iabi l i ty for the con

tac ts to ac t as a trembler or chatter,owing to the

vol tage of the dynamo being too near that of thebattery for the cut - out real ly to dec ide whether i tshal l stay on or off.

The general tendency is,therefore

,agains t the

electri cal cu t - out as too del icate for commerc ial purposes ; there is , however, a certain electro -mechan icalmod ificat ion wh ich may be described .

Tée Fr ee Wéeel Cut—Out.

—~As we have po in tedout al ready

,i f the current from the cel ls be all owed

to flow back through the dynamo,i t wil l tend to

become a motor , and in the sys tem we are describ ingthis i s actual ly al lowed to occur

,but i n the pu l l ey

wh ich drives the dynamo is placed a free wheel,

p Scre w

Fig. 1 7 .

WIRING THE CAR 25

s im ilar to tha t used on a bicycle . The dynamo thenbecomes a mo tor

,bu t can rotate freely w i th no

tendency to turn the engine ; when , however , theengine Speed is suffic ien t to generate , the free wheeltakes up

,and the mo tor is then driven by the engine

as a dynamo .

The free Wheel is arranged to give a slight cl i ckingnoise

,so that the fac t that the dynamo is motoring

shal l no t be overlooked when leaving the car for then igh t

,the main charging swi tch being then turned

off. The‘dynamo when runn ing as a mo tor takes

only abou t 1 to 2 amperes wh ich does not matterduring the short periods in ac tual dr iv ing in whichmotoring”occurs .

Mechanica l Cut-Outs — These cons ist almostwithou t exception of a cen tri fugal arrangemen t ,whereby when the governor weigh ts col lapse owingto the s topping or in suffic ien t Speed of the mach ine ,the contac t poin ts are forced apart by a spring act ingin oppos i t ion to the governor . Ano ther me thod cons is ts of a disc ro tat i ng in a mercury bath : when thespeed of the d isc is suffic ien t ly h igh . the mercury i scarried round , and makes con tac t - wi th an insulatedplug , thereby clos ing the ci rcu i t .

The various dev ices wi l l be described more ful lyin relat ion to the machines i l lustrated in the fol lowingpages .

CHAPTER IV

PERMANENT MAGNET SYSTEM

Mira .- The dynamo we propose to describe firs t i s

the Mi ra Magnetolite (Fig . which , i n troduced in1 909 ,

has been very l i ttl e al tered in pr inc iple s i ncethat year

,and s ince i t i s the s imples t of a ll dynamos

wi l l serve asunders tood .

The magnetolite system cons ists essent ial ly i n

F ig . 1 8 .

an example wh ich can be eas i ly

employing a permanen tmagne t i c field to exci tethe armature which ro tatesbetween the magne t poles ,and

,furthermore

,to use

the fixity o f th is magnet icfield to l im i t the ou tpu t ofthe dynamo a t h igh speedsso that heavy currentsshal l not des troy the ac

cumula tor or burn out thelamps .

F ig . 1 9 shows a sect ion of the dynamo from

which the s impl i c i ty Of the machine wi l l be readi lygrasped .

The dynamo i tsel f cons i s ts of three or fourpermanent magne ts of three blades or lam inat ions each , be tween the pole s of which ro tates alam inated tunnel armature carry ing the usual coppercommutator , and moun ted on bal l bearings at each

PERMANENT MAGNET SYSTEM 2 7

end . One of the bearing end - plates carries thebrushes which col lect the current , the other bearing

Fig . 1 9 .

plate carries an insulated Sl ip r i ng wh ich serves tocarry the current from one brush to the cu t - out (F ig.

which is located inthe alum in ium pulley , C onfi rm.

and cons is ts of a smal l u "

balance weigh t working by cen tri fugal forceagains t the ac t ion Of aspring which tends to Pa n“,

keep the con tacts separated . One Of thesecontacts ‘

i s the brush s pa m ,

h o l d e r w h i c h c om Fion z o .

munica teswi th the l iveSl ip ring and the nega t i v e brush , the o ther is theearthed balance we igh t .

Referring to the diagram , Fig . 2 1 , i t wi ll be seenthat when suffic ient speed is obtained to generatecurren t . the balance weigh t fl i es ou t and earths thenega t ive brush , thereby put t ing the mach ine in c i rcu i tprov ided the chargi ng swi tch is closed . From the




Figs . 25, 26 are the accumulators and F igs . 2 7 ,

28,29 ,

lamps usual ly suppl ied wi th these sets , and theord inary garage wi ring d iagram is shown (F ig .

F ig . 22 .

A rmoured cable i s employed wi th a Si ngle l iveconductor to convey the curren t ; the return from thelamp being via the armouring or frame back to the

Fig . 23

battery and base of the dynamo , thence by the earthedcu t - out to the negat ive brush .

The Mi ra machine holds an R.A .C. Cert ificatefor m iles of sat i sfactory behav iour .

CHAPTER V

PERMANENT AND EL ECTRO -MAGNET SYSTEM

Ducellier.—This dynamo (Figs . 3 1 and though

employ ing permanen t field magnets , works on an

enti rely d ifferen t princ iple to the last described , i nthat i t has two field wi ndings , one to supplemen t themagne t i sm of the permanent magnets and anotherwound i n the oppos i te sense and connected to a

Fig . 3 1 .

third brush to demagne t i se the fields when the speedsrise above a certa in l im i t .The speed of the dynamo rises to a maximum of

the ful l ou tpu t be in ~ i ven atThe current i s col l ected by two la " m brushes from awide copper commutator , the brush Simplyserv ing to control the maximum I t th rough thefie ld w ind ing .


To prevent the battery d ischarging through the

dynamo when the mach ine ceases to rotate , a nea t

Magnets

Fig . 32 .

brass case con tain ing an elec trical cut - out i s prov idedwh ich may be fixed to the dash or other su i tablepos i t ion (Fig . This cut- out when once fi tted

Fig. 33. Fig . 34 .

should requi re no adj us tmen t and should not beinterfered wi th .

The dynamo i tsel f is prov ided wi th Sl ide rai ls t ot ighten the bel t

,thereby obv iat i ng cutting of the same .

PERMANENT AND ELECTRO -MAGNET SYSTEM 35

The output of the Ducellier dynamo is 200 wat ts,

Fig . 35.

that i s 1 5 amperes at 1 2 - 1 4 vol ts,accord ing to the

s tate Of charge of the battery .

The swi tchboard (F ig . 34) carries three swi tches ,


the two outer ones con trol l i ng respect ively the two

head lamps and the s ide and dash,the thi rd the

dynamo . There are al so mounted on the board

Fig . 36.

sui table ammeter and vol tmeter, these instrumentsbeing always in c i rcui t .The batter ies (F ig . 36 ) suppl ied are of 1 2 vol ts

and have capac i ty of 60 , 80 ,or 1 00 ampere hours to

cho ice .

The Ducellier set is completed by a series of veryhandsomely -finished lamps , hav ing parabol i c reflectorsconstructed of s i lvered copper (F ig . 3



regulat ing the output of the mach ine . This arrangement ensures absolu tely perfect commutat ion .

When the speed of the mach ine has i ncreasedsuffic iently to supply curren t to the l ine

,an armature

react ion is se t up which reduces the current i n the

res istances ; th is act ion increases un t i l there i s nocurrent at al l between the main and auxi l iary brushes

,

as they wi l l be at equal poten t ial s . F ig. 39 gives thecurves showing th is act ion .

Fig . 38 .

The machi ne is very subs tan t ial ly constructed,

espec ial ly so the commutator and brushes . The

armature rotates on large bal l bearings and Sincethe speed of the mach ine i s low for i ts outpu t thewearing parts should last i ndefin i tely .

The cut - out d iffers from the O lder patte rn Of

T. 8: M. ,as i t i s now of a magne t i c type , of pos i t ive

act ion,with large con tac t surfaces , and requ i res no

adj ustment .

ELECTRO -MAGNETICALLY GOVERNED SYSTEM 39

It cons ists of an elec tro -magnet control led by acombination of wind ings which operate a p lungerso as to “make and b reak the main c i rcui t whenthe dynamo is runn ing at or below i ts generat ionspeed .

Two types of mach ine are made,one giv ing an

output of 1 0 - 1 2 amperes at 1 2 volts the o ther 7 - 8

amperes at 1 2 vol ts,with a maximum output of 1 80

and 1 20 watts respect ively .

Fig . 39 .

A , Current to the l ine w ires.

B, Curve show ing cu rrent between a ma in and auxiliary brush .

c, Point a t which machine sta rts to supp ly current to the line w ires.

-D,Point at which the aux il ia ry brush is neu tra l .

Fig . 4 1 shows the s tandard type of lamp usual lysuppl ied wi th th is outfi t .

Various types of swi tchboard are provided to su i tind iv idual tastes

,but al l have an ammeter and two

controls— one for charg ing the battery,and the other

for selecti ng the part i cular l ights requi red . F ig . 40

i l lustrates one

4 0

’

DYNAMO LIGHTING FOR MOTOR CARS

A field fuse i s prov ided to protect the dynamoshould anything go wrong with the wi ring .

Fig . 40 . Fig . 4 1 .

The accumulators suppl ied wi th the set have acapac i ty of 40 ampere hours at 1 2 vol ts , and We igh

48 lbs. The battery box i s prov ided wi th detachable

Fig . 42 .

Catches , so that i t can read i ly be removed for clean inga nd examinat ion .

C.A.V .

—A very popular dynamo of s imple des ign

ELECTRO-MAGNETICALLY GOVERNED SYSTEM 4 1

i s the C .A.V . (Fig . This mach ine i s verysim ilar to the ord inary shun t wound dynamo , excep tthat i t i s fi t ted wi th two aux i l iary unwound polesN

,S (F ig. The effect of these poles i s to shun t

Fig . 43 .

the d is torted magne t i c flux back through the bodyof the mach ine when h igh speeds are at tained

,i ns tead

of al lowing i t to traverse the armature i tsel f,thereby

keeping the output pract i cal ly constan t even ath igh speeds . The arma ture (F ig . 44) i s drum wound

,

hav ing a 48- par t copper commu tator . The brushes

4 2 DYNAMO L IGHTING FOR MOTOR CARS

( two in number) are suffic ien tly wide to short - c i rcu i t twowind ings of the armature

,thereby cross m agnet is ing

the armature , and aid ing the shunting f effec t of the

F ig . 44 .

subsid iary poles as above descri bed . A t the end ofthe armature shaft with i n the driving pulley i s foundthe free wheel wh ich takes the place of the cu t - outas ord inari ly known . This free wheel ’

is s im i lar to

Fig . 45. F ig . 46 .

tha t usual ly found on bicycles,but wi th s tronger

springs , fi t ted so that,when free wheel ing or

‘

motoring ,

the t icking noise draws a ttent ion to the fact that thedynamo has no t been swi tched off.


The working of the free wheel is as fol lows : assoon as the pulley is driven by the engine at a speedsuffic ien t to en

able the dynamoto begin to generate (abou t 500R. t h epawl engages

,

and the dynamocommences to bedriven un t i l sucht ime as the pul leyspeed fall s below

500 , when thed y n am o t a k e scurren t from thebat tery and runsas a mo tor , thefree wheel overr u n n i n g t h eengine or mot o r i n g . Th i sm o t o r i n g w i l lconunue evenwhen the engineis s topped

,bu t

t h e m a x i m umcurren t taken wil lonly be abou t 15amperes which i sprac t i cal ly negl i o a an F 1 n a a

g ible . When the S3 8 3 dWVcar i s left for

any cons iderable period , the charging swi tch must beturned off, the t i cking of the free wheel drawingattent ion to this fac t . The curren t was ted in the free


wheel i s very smal l , probably not more than that consumed in the coi l s of a magnetic type of cut - out

.

Fig . 48 .

This dynamo is made in s ix s i zes,the standard

o r E type giv ing 6 amperes at 1 2 vol ts,and weighing

2 1 l bs .

Fig . 49.

The standard swi tchboard (Figs . 45, 46 ) providedwi th these sets is o f the slan t ing desk pattern

. com



g iven to the excel len t system of w iring'

(Fig .

Spec ial sp i ral ly wound brass armoured conductors are

Fig . 52.

suppl ied to conform to the cond i t ions requ ired , vi z .,

conductors for the lamps,di tto for the main wires from

Fig . 53 .

the battery and from the dynamo (th i s al so carriesa th i rd wi re

.

for the field c i rcu i t ) . Owing to thestrength Of the armouring there i s no need t o

EL EC'

I‘

RO-MAGNETICALLY GOVERNED SYSTEM 4 7

draw the wi res through Copper tubes , e tc . , and thewi ring of the car i s much faci l i tated .

V‘ ”

RI GKIWK

Fig . 54.

Fig. 55.

T his dynamo has been awarded an R. Certifi

cate for m iles performance .


Brolt — The pri nc iple of the Brolt dynamois somewhat s im ilar to that of the last machinedescribed in that i t has two auxi l iary poles (Figs . 53 ,

54 , These aux i l iary poles carry no wind ing but

TYPEC4 .

REVOLUTIONS PERMINUTE.

Fig . 56 .

are exc i ted by the cross magnetisat ion caused by theworking curren t i n the armature .

Th is mach ine has also but two brushes which arew ide enough to short - c i rcu i t several armature co i ls

Fig 57 .

during the period of commutat ion , as shown by theblack dots in the d iagram .

- Any increase in speedcauses a consequent short- c i rcui t ing curren t in thesec

'

o i ls which reacts and weakens the mai n field,keep ing

the outpu t current constant (F ig . For conven ience


each wide brush is actual ly d iv ided in to halves , the twobe ing electri cal ly connected together.This dynamo reaches i ts ful l output at a very low

speed , thereby saving undue wear and tear of thebea rings and commutator . The armature i tsel f (Fig.

57 ) i s devo id of any cut - out fi tt ings,be ing the only

mov ing part i n the system ,the cut - out proper be ing a

magne t i c one of the usual type fi tted wi th i n the swi tch

Fig . 58.

board , which has several novel po in ts of des ign(Fig .

A combined amme ter and vol tmeter is employedlocated at the top of the board

,while d i rect ly under i t

i s a window ind icat ing the lamps turned on by theknob at the s ide . The combinat ions given by the

swi tch are

1 . Dynamo and lamps off.2 . Dynamo charging .


3 . Dynamo charging ,Side and tai l .

4 . Dynamo charging,head ,

’

side,uand tai l .

5. Dynamo charging,head a nd tai l

The vol tage can be read by press ing a button onthe right - hand s ide wh ichmomentari ly d isconnectsthe main charging current .

Should the tai l lampgo out

,a smal l lamp

l ights up beh ind the red

window, On the left hands ide of the board , therebyacting as .a tel l tale wi tho ut thenecess i ty of carry

ing a double quant i ty of spare bulbs . A plug for

i nspect ion lamp is prov ided,also a fuse to pro tec t

the battery.

The standard type dynamo g ives an output of6 amperes at 1 2 vol tsat RWP M andweighs 25 lbs . , theswitchboard we igh ing

3& lbs . The batteryusual ly suppl ied has acapac ity of 3 3 ampere

hours at 1 2 vol ts,and

is put up in a neat teakcase for fixing on therunn ing board of the car ;a very neat se t of lamps is also supplied

‘

w ith th is se t .

Fig 59

Fig . 60 .

L eitner.—The L e i tner dynamo (F igs . 59 , 60 ) was

one of the first mach ines to“be

"

successfully used on

cars and i s s imply an ord ina ry shun t wound dynamowi th an addi t ional subs id iary brush or brushes .

ELECTRO-MAGNETICALLY GOVERNED SYSTEM 51

The fol lowing descript ion appl i es to a 4-brush

mach ine —N and s (Fig . 6 1 ) represen t the two polepieces and C and C, the two main b rushes wh i ch are

connected to the main c i rcu i t through the auto swi tchort cut- out. The shun t windings C

,have one of the i r

Fig . 6 1 .

ends connected to these brushes,the other ends be ing

Connec ted Wi th the subs id iary brushes D and D,.

If the d i rect ion of ro tat ion be counter - Clockwisethere wil l be a d ifference of pressure between the

.D and D thIS wi l l aid the rap id

exci ta t ion of the poles N and S. But as the curren ton load flows out of the armature through C and C

,

D 2

52~ DYNAMO . LIGHTING FOR MOTOR CARS

the armature magnet i sat ion d is torts the field magnetism in the d i rect ion of rotat ion and in consequencethe vol tage be tween the subs id iary brushes is firstlowered and then reversed in Sign . This voltage

,

which increases wi th speed and load , opposes that ofthe field , so that the latter is weakened in proport ionby counter EM F .

The machine i tsel f i s strongly constructed and wellenclosed , the armature runs on bal l bearings and givesits rated output at revolut ions i n the smal l s ize andat in the large , the mach ine be ing wound to give

Fig . 62.F ig . 63 .

1 2 vol ts . We igh ts of mach ines , 60 watts 1 7 lbs . ,1 20

watts 1 9—5lbs . The auto swi tch or cut - out (Fig 6 2 )

i s of the electro -magnet ic type al ready described andi s general ly fixed wi th in the swi tchboard (F ig.

This lat ter i s of the sloping desk variety and contai nsvol t and amme ters

,also a progress ive sw i tch or

“combinator”by which various select ions of lampsand charging may be obtained . These are as

fol lowsDAY RUNN ING

Off—Dynamo running light.0n .

—Three-

quarters or fu l l charge (depending on typeCha rge3

I selected ) .


54 DYNAMO LIGHTING FOR'

MOTOR CARS

If al l four are at the top the ac id i s too strong, andwater should be added . Three beads ind icate thecel l i s ful ly charged , two beads that the cel l i s about

two - th i rds charged one bead one - th i rd charged , andno beads float ing Ind icates that the battery is practical ly ful ly discharged . The capac i ty of the batter iesvari es from 20 to 55 ampere hours depending on

Fig . 68 .

how much n ight runn ing is ant ic ipated i n relat ionto the day charging .

F igs . 66 , 67 Show the general appearance of thelamps usual ly employed wi th this set

,also a sect ion


o f t h e h e adlamp (Fig. 68 )showing thes c i e n t i f i c a l l ydes igned parabolic reflector.AS i n someearly patternsthe lampholders

are non - focuss ing

,the bulbs

suppl ied by themakers Shouldbe used in orderto ge t the filament in theexact focus .

F ig . 69 showsthe output curvecharacteri s t i c ofone of the standard mach ines .

The s teadinessof the ou tpu twil l be no t i ced

,

also the earlycutting inspeed .

The wiringof th is sys temi s g e n e ra l l ycarried out i nflexible metall i c tubing wi thspec ial bushesfi tted at the ends and j unct ions to preven t frayingof the conductors .

La n d - M N - O Q OO F to m d 'flNF 91 704

CHAPTER V II

EL ECTRO MAGNETICAL L Y CONTROLLEDSYSTEM

Mag ician.

—The Magic ian dynamo , while giv ing alarge output

,ach ieves i ts end in a very i ngen ious way .

The whole body of the dynamo (Fig. 70 ) i s p ivotedconcentrical ly wi th the spindle

,thereby al lowing i t

Fig . 70 .

to sw ing through an arC'

which i s l im i ted bystops . The dynamo i s normally kept i n pos i t ionagains t one stop when at rest by a spring , but assoon as the armature commences to rotate and

g enerate , the carcass begins to fol low in the same

ELECTRO -MAGNETICALLY CON TROLLED SYSTEM 57

d i rection t i l l i t meets the further stop . The mainbrushes are moun ted on the swinging carcass a ndCol lect the curren t i n the usual way

,bu t a th ird fixed

brush is connec ted to the field wind ing , so tha t whenthe speed i s low (be ing in the maximum pos i t ion ) i tenergises the fields strongly

,bu t as the speed increases

and the carcass begins to turn , the brush gradual ly

Fig . 7 1 .

reaches a more and more ineffic ien t col lect i ng spot,

thereby weaken ing the field and keeping the ou tpu tconstan t .

The turn ing of the carcass i s furthermore u t ilised to effec t the cu t t ing i n and ou t ( 7 , 8

, 9 ,

F ig .


The automati c cut - out switch 1 2 ,F ig . 70 ,

thusactuated ,

closes the c i rcui t at abou t 800 revs . per

minute .

Should a short - c i rcu i t occur , the rush of currentrocks the field ..magnets over, and the dynamo cu tsout and cuts i n unt i l the short - c i rcu i t IS rect ified ,

FIEL DWINDING

F ig . 7 2.

making a suffic ien t no ise in . the process. to attrthe driver ’s attent ion .

Another advantage is that the di rect ion of rotat ionmay be altered by moving the exc i tat ion brush

,

‘ad ifferen t brush cover obtainable from the makers be ingall that i s necessary .

ELECTROM AGNETICALLY CONTROLLED SYSTEM 59

.60 DYNAMO LIGHTING FOR MOTOR CARS

The ebon i te brush cover is a special fea ture ; a ll

wire connect ions except the exc i tat ion carbon arecon tained in this cover . F ig . 7 1 shows the brushesbeing taken out .

F ig . 7 2 shows the Wi rIng system . The field or

exc i tat ion term inal E i s here shown , and may be seena t Fig . 70 ,

which connects It'

w ith the exc i ta

Fig . 74 .

t ion brush ,1 I . This

‘

brushf is carr i ed on an adjustableb racke t ; by mov ing th is bracke t the outpu t of thedynamo can be varied to any value between 8 and 20

amperes .

The output i s 1 80 watts at 1 2 vol ts,which is


6 2 DYNAMO L IGHTING FOR MOTOR CARS

The only feature of importance is the doublew i nd ings . on the field , which are somewhat l i kethose u sed on a compound - .machine bu t act ing '

In

the.opposi te sense . The first winding is the usual

shun t wind ing connected over the brushes and

energis ing the field i n the usual way . The secondw i nd ing cons is ts of a few turn s of coarse w ire

,bu t

wound to energise the field i n the oppos i te way toshunt , ‘

and connected In series wi th the batteryand main c i rcu it . The act ion of this arrangement i sas fol lows : A t low speeds the shunt co i l begins tomagnet ise the fields , and a current i s generated inthe armature . Th is curren t i s at fi rs t , owing to thelow speed of the a rmature , qu i te feeble , and themagnet ism due to the shunt co i l w i l l mount w iththe Increas ing Speed of the dyn .amo When ,

however,

the speed of the machi ne r ises,and therefore the

strength of the curren t begins to approach the poin ta t which i t m ight be "i nj urious to the battery andlamps , the current i n the series co i l w il l be foundstrong enough to exc i te a counteract i ng influence on theshunt coi l

,and any further increase of speed wi l l be

neutral ised by the current flowing round the main orser ies co il

,which , as we have said , acts in oppos i t ion

to the shun t or bui ld ingup co i ls .

In this way a very s imple and effic ien t mach inehas been constructed giv ing an excel l en t output curve

(F ig .

F ig. 7 7 shows a sect ion of th is mach ine and g ivesdetai l s o f the working parts . It wi l l be noticed/tha tthese are of the smal lest number to give effic ien twork ing

.

and are generously proport ioned .

ELECTRO ~MAGNETICALLY CONTROLLED SYSTEM 63


Fig . 78 shows one of these machines instal led on a

chass is and driven from the flywheel .

REFERENCE—A ,A,

Shaft : n, carcass ; C, commuta tor ; E, lock nut ; F , cab les ; G , G , lubricators ;11 , H ,

inspection cover 1,a rma ture ; K ,

pulley key ; R , R , ba l l bearings.

F ig . 7 7 .

F 1g . 7 8 .

The ou tpu t given by these mach ines is cons iderable

,that of the large type be ing 25 amperes at 1 2

vol ts or 300 watts .

ELECTRO -MAGNETICALLY CONTROLLED SYSTEM 65

In order to preven t the curren t runn ing back fromthe batte ry to the dynamo when the engine is stopped ,

Fig . 79.

a cut - out of the usual electro - magnetic type is in te rposed (Fi . be ing usual l y fixed to the dashboard

,

Fig . 80 .

‘or where i ts sat isfactory operat ion can from timeto t ime be observed .

Owing to the large output of th is machine theE


makers prefer to supply thei r own special accumulator(F ig . Th is should be of at l eas t 40 ampere hourscapac i ty at 1 2 vol ts . The cel l s are of cel l ulo id pu t upi n a pol i shed Case wi th ou ts ide term inals plainlymarked . N0 s tandard sw i tchboard i s i ssued wi th th isse t , the various ammeters

,voltme ters

,and swi tches

be ing mounted i n accordance w i th the requi remen tso f each car .

The swi tch con trol l ing the lamps is progress ive i na ct ion

,the sequence of l ighti ng being as fol lows

Fig . 8 1 .

F irs t s top— Side and ta i l on .

Second stop—H ead ,s ide , and tai l on .

Th i rd s top— H ead only .

Fourth stop— A l l off.

A separate swi tch con trol s the dynamo c i rcu i t .Figs . 8 1 , 8 2 Show the head and s ide lamps suppl iedwi th th is set , the reflectors be ing parabol i c and constructed of s i lver rol led on copper .

Polkey -"a rrott.— The me thod of maximum control of the Polkey -"arrott dynamo (Fig . 83 ) i s verys im i lar to that of the las t descri bed machinep zn thati t has a di fferen t ial ly wound series co i l i n oppos i t ionto the main field for l im i t ing the maximum ou tput

ELECTRO-MAGNETICALLY CONTROLLED SYSTEM 6 7

The dynamo i tsel f is designed to charge a 1 2 - vol t

Fig . 83 .

Fig . 84.

battery, at 65 amperes , g iv ing 74 actual candle - power,

that is , two head lamps of 24 candle -power, two s ideE 2

68 DYNAMO LIGHTING FOR MOTOR CARS“

lamps of 6 candle—power i n ser i es,also the tai l and

inspect ion lamp in seri es .

The dynamo is very substantial ly constructed, runs

Fig . 85.

on bal l bearings,and has a heav ily constructed copper

commutator , each of the three brushes be ing d iv ided

Fig . 86

i n to two parts having c ircular brushes . Two of thesebrushes are the usual main col lectors

, the th‘

irdxoa rries

curren t to the field regulati ng coi l i . n'



F ig. 85 shows the swi tchboard , which is fi tted withan ammeter and four swi tches control l i ng respec t ivel y

Fig . 88 .

the charging head lamps ( i n paral lel ), Side lamps (inseries ), and the tai l lamp .

The batte ry wi th connec t ing plug at the s ide is

Fig . 89.

shown in F ig . 86 . The cel ls have a capac i ty of 55ampere hours at 1 2 vol ts.

The head ,s ide , and tai l lamps are shown respec

tively i n F igs . 87 , 88 , 89 . A novel ty i n thei r manufacture i s the abol i t ion of hinges and catches the fronts

ELECTRO -MAGNETICALLY CONTROLLED SYSTEM 7 1

of the lamp fi tt i ngs are l ike the face of a watch , therebygiv ing a very clean fin ish

,and renderi ng the lamps

wa ter and dus t proof.This set has gained an excel lent R.A.C. Cert ificate

for m i les runn ing wi th all lamps on , n igh t runn ingonly be ing al lowed .

Facile — The Faci le dynamo (F ig . 90 ) i s amachine of s trong and s imple construc t ion . The

dynamo i tsel f is an ord inary shunt wound mach inetotal ly enclosed

,the armature runs on bal l beari ngs

and is fi t ted wi th a rnassive commu tator from wh ich

F ig . 90 . Fig . 9 1 .

the current i s col lected by spring loaded carbonbru shes .

The dynamo i s connected to the control le r (F ig .

9 1 ) by three wi res , the two main leads and the shun tlead respect ively . The control l er cons ists of theusual electro -magnetic cut - out , with the add i t ion of afurther contact , the use of wh ich i s to cut a res is tanceinto the s hunt c ircu i t , and thereby weaken i t on thespeed of the dynamo becoming excess ive . The seriesof operat ions wi l l therefore be as fol lows : When thedynamo generates suffic ien t vol tage to begin chargingthe battery , the cu t - out armature i s attracted andcloses the c i rcui t ; this should occur at a car speed ofabout 1 2 miles an hour . The outpu t wi l l now rise t i l lthe armature o f the cut - ou t i s further at tracted by the


magnet and an add it ional res istance i s in terposed in

the shunt c i rcui t,thereby weaken ing the field so tha t

any further speeds up to say 55 miles an hour wil l no tdamage“ the accumulators or lamps .

The current from the control ler is taken to thebattery

,thence to the swi tchboard (F ig . from

which i t i s d is tributed to the lamps in the usual way .

Fig . 92. Fig . 93 .

The head lamp usual ly suppl ied wi th th is se t i s showni n F ig . 93 .

The s i ze of accumulator recommended for use wi thth is set i s a 60 - ampere hour battery at 8 vol ts . The

weigh t of an 8 - vol t dynamo giv i ng 8 amperes i s

45 l bs . , extreme strength and s impl i c i ty being themain obj ect .

The Bosch — The dynamo in troduced by thewel l - known firm of Robert Bosch fol lows in princ ipl econvent ional l ines , the grea t - aim be ing to secureconstant output . The machine , F ig . 94 ,

i s of the usualshunt -wound type , the output be ing controll ed byvariable res is tances located .wi th in the sw itchbox .

Shutters are provided a t the end of the mach ine to

ELECTRO - VIAG NETICAL L Y CONTROLLED SYSTEM 7 3

i nspect the commuta tor and to remove the brusheseasi ly . The dynamo begins to generate i ts correc tvol tage ( 1 2 vol ts) a t the low speed of 350 R.P.M .

Fig . 94.

Owing to the effic iency of the regula tors prov idedthe outpu t of the generator is independen t of anyaid the bat te ri es , and these lat ter may be

Fig . 95.

d isconnected , i f so requi red,wi thou t i n the leas t

endangering the bulbs .

The swi tchboard , Fig . 95, i s of me tal , and contains


not only the field regulator but also the cut - out , whichbri ngs the battery in to c i rcu i t when the correc t pressurei s attained by the dynamo . The i nstrument at thetop is a combined vol t and amme ter .

Tw o swi tch levers a re prov ided ; one connec ts thebattery di rect to the lamps , or puts the dynamo andbattery together i nto act ion the second lever swi tcheson ( I ) the s ide and tai l lamps , (2 ) the head , Side , andtai l lamps

,or (3 ) the head and tai l lamps only . The

Fig 96 .

system of wi ring is very complete and thorough,

employing a single i nsulated conductor wi th a braidedearth return s im i lar to that described on pp . 20 .

and 3 1 .

The lamps , F ig . 96 ,are of the usual parabol i c

des ign , wi th careful ly curved reflectors wh ich project .

the l ight ahead in an effect ive manner,yet wi thou t

dazzle . The lamps are qui te water and dust t ight, and

of handsome appearance .

ELECTRO-MAGNETICALLY CONTROLLED SYSTEM 75

The output of the dynamo i tsel f i s 1 00 wat ts at1 2 volts , a t a normal rate of revolut ion .

The Eisemann dynamo , F ig . 9 7 , has several

poin ts of novel ty i n i ts construct ion , al thoughmach ine i tself is of s tandard des ign .

Fig . 98 .

The body cons ists of an enclosed carcass wi th theupper pole only exci ted wi th a s ingle winding. The

armature , F ig. 98 , i s drum wound,eas i ly demountabl e


brushes and holders col lec t i ng the curren t from thecommutator.

Si tuated at the top of the mach ine (F ig . 99) arethe organs of regulat ion . These cons is t of threeelectro -magnets i n terconnected . The first magnet actsas the ord inary magnet i c cu t—out ; the second breaksthe c i rcui t Should the curren t ra te become excess ive ;whi le the th i rd breaks the c i rcui t should the vol tage

Fig . 99.

o f the.

cel ls ri se above certain l im i ts . The output ofthis model i s 1 80 wat ts

,or 1 2 vol ts 1 5 amperes , cut

t ing in at 400 and atta in ing i ts maximumo utput a t R. P.M.

The sys tem of wiring is wi th armoured cablehaving a cen tral l i ne conductor

,the return be ing

by the armouring or earth as described on p .

3 1 .



The swi tchboard , F ig . 1 0 2 , of pol ished mahogany,i s arranged for concentric wi ring

,wi th the tai l and

dashboard l ights in series .

Fig . 1 02 .

An armoured braided concentric cable is used theou ter braid ing tak ing the place of a negat ive wi re

(see p .

CHAPTER V III

MECHAN ICAL L Y-CONTROL L ED SYSTEM

L ucaS.— The L ucas dynamo is of notably s imple con

struction . The mach in ei tsel f (Figs . 1 0 3 ,

1 04) i sexc i ted by a Si ngle shun tco i l

,this Coi l be ing cu t

”m amou t of ac t ion when thedynamo is swi tched off,

thereby reducing fri ct ion to the m in imum .

A 1 6 - sec t ion drum wound armature rotates on bal lbearings and is furnished wi th a verym a s s i v e c opp e rcommutator of conventiona l des ign COMMUTATOR

from wh ich twoBRUSHHOLDER

s tou t Morgan i te ANDBRUSHES

brushes col lec t thecurren t . The main

po lnt Of novel ty 1 11

5

END covea nsmovsoHOWING COMMUTATOR BRUSH GEth is mach ine IS the AR

means adopted of

ensuring the l im i tat ion of excess current , which i s oh

ta ined by the use ENocovm

of a sl ipping clutch

placed ins ide the drivi ng pul l ey . This clutch con

Fig . 1 0 3 .

FIXING SCREW

Fig . 1 04.


s i s ts of a fibre - covered cone at tached to the dynamo

shaft but free to s l ide and pressed in to con tact wi ththe cone Of the pul ley by a strong spring . Wi th i nthe clutch are four smal l balance weights which act

by cen tri fugal force,and

tend to force the clutchout of engagemen t agains tthe Spring .

When the speed of thedynamo is h igh enough

,

t h e s e w e i gh t s a c t i n gagains t the spring partia lly withdraw the clu tch ,

al lowing sl ipping to takeplace , thereby l im i t i ng theoutput of the mach ine . The s l ipping poin t of theclutch (and therefore a pre determ ined outpu t) canbe arranged by an adj ust ing nut at the end of theshaft which compresses or loosens the spring govern

F ig . 1 05.

Fig . 1 06 .

i ng the sl ipping po in t a t wil l . The clutch i tsel f , is

enclosed and kept lubricated with th in o i l .The output of the dynamo is 1 00 watts (weight

25 lbs . ) i n the smal l s ize and 200 watts (weight 35 lbs . )i n the large

,pressure 1 2 vol ts .

To break the ci rcu i t an ord inary elect ro -magneti ccut - out is employed located wi th i n the

MECHAN ICALLY-CONTROLLED SYSTEM 8 1

1 05) which also carries an ammeter and vol tmeter andswi tches control l ing the charging , head , s ide , and tai llamps , also a swi tch for w ork ing the tel l - tale or pi lotbulb on the board i tself. Should the tai l lamp go outthe tel l - tal e bulb wi l l l ight up

,thereby ind icat i ng that

some thing i s wrong . The te l l - tal e can also be workedindependently .

Spec ial L ucas accumulators (Fig . 1 06 ) are suppl ied

of 50 - ampere hour capac i ty i n ac id - proof woodenboxes

. The elements i n th is battery are cyl i ndricali n shape

,separated by porous pots

to el im inate short - c i rcui t i ng and prevent buckl ing .

F igs . 1 0 7 , 1 0 8 ,1 0 9 show the se t

of lamps . A poin t about the headlamps worth no t i c ing i s that theback of the projec tor (wh i ch i s of

the parabol i c type ) i s de tachable toge ther wi th thebulb and holder

,so that the whole ou tfi t i s read i ly

i nspected wi thou t open ing the fron t of the lamp , anoperat ion always l iable to al low the ingress of mudor dus t .

Peto and Radford .

—The Pete and Radforddynamo is of the total ly enclosed four- pole shun t


Wound type , wi th a cen tri fugal sl ipping pul ley to

preven t excess speeds (Fig .

An alum in ium cas ing at one end admi ts of ready

access to the brush gear, which is s imple and substantia l .

The armature , which i s tunnel wound,runs on

bal l bearings .

Fig . 1 1 1 .

The dynamo is suppl ied i n three Si zes,giv ing

90 ,1 50 ,

and 250 watts respect ivel y and wound for1 2 vol ts .

The smal l set wh ich measures 8 x 6 x 6 , weighs

2 1 lbs,and the large

,which is a four - pole machine ,

measures 9 x x 75.

VIECHANICAL L Y-CONTROLLED SYSTEM 83

The maximum ou tput of the dynamo is con trolledby two types of governed pul leys

,one of which is

shown (Figs . 1 1 1,

‘

.The mechan ism i s arranged

Fig . 1 1 2 .

o n one s ide of the pul ley F and consis ts of twoweights D

,D act i ng through toggle l evers K and L

which work against the ac t ion of a spring ". This

Fig . 1 1 3 .

rspira l spring presses the fric t ion plates M sl id ingo n :the shaft A against the cheeks of the pul leyi tsel f and i ts tension ,

and therefore the govern ingF 2


speed can be varied by means of an adjustablecol lar H . The pul ley i tsel f runs on a bal l race E

kept i n place by a col lar B. G i s a detachable dustcover .

A t speeds of or 850 , R.P.M. for therespect ive dynamos , the governor we ights beg i n to

compress the spring and al low sl ipping to take placebetween the fric t ion d isc and the pul ley

,thus l im it i ng

the output of the dynamo .

A cut - in and cut - out of theordinary electro -magnet i c typei s employed to preven t the current from the battery flowinginto the dynamo when at rest

,

F ig . 1 1 3 , which also shows ad istr ibut ion box combin ed wi ththe cut - out and wi th fuses inseries wi th each c i rcu i t , therebylocat i ng any short - c i rcu i t whichmight occur more eas i ly thanwi th the more usual s ingle mainfuse .

Fig . 1 1 4 shows the de "axe Fig . 1 1 4 .

swi tchboard suppl ied wi th set .It has a separate ammeter and vol tmeter with ani l lum inating bulb wired in series wi th the tai l lampfor read ing the d ials at n ight . Separate swi tches control the two head , s ide , and tai l lamps independently ,

and another swi tch is suppl i ed to control the batteryign i t ion . Pin plugs are provided for the i nstal lat ionof inspect ion lamps , etc . Other types are suppl ied .

The batteries recommended for use should havea capac i ty of 42 to 50 ampere hours at 1 2 vol ts

,

accord ing to the system chosen . F ig . 1 1 5 showsthe battery complete i n i ts t ray ready for l i ft ing out ofthe pol ished wood case for inspect ion . F ig . 1 1 6 shows



E.B.C.

— This dynamo is of the shunt - wounddrum total ly enclosed type . Irregular speed is counteracted by the armature being driven through a .

= cones l ipping clu tch

,actuated by a centri fugal four- arm

governor which exerts an axial pressure over theins ide face of the cl utch ; the governor i s arrangedto control the armature speed at bu t bymeans of an access ible r ing bol t th is act ion can beal tered and the amperage varied

,thus any number of

'

F ig . 1 1 7 .

candle - power lamps may be used wi thout underor over loading . F ig . 1 1 7 shows the various parts . In

place of a cu t-out there i s a free -wheel clutch,and

the dynamo is permanently connected to the accumulators as long as the swi tch is on. Should the swi tch beleft on whils t the car is at res t

,the accumulators run

the dynamo as a motor . There is thus no danger ofthe armature short - c i rcu i t ing the batteries

,but the

swi tch should -not be left on,and the free -Wheel g ives

a cl ick ing no ise as a warn ing .

MECHANICALLY -CONTROL L EI ) SYSTEM 8 7

The dynamo is suppl i ed in th ree s izes , No . I hav ingan 80 - watt ou tpu t , and wound for 8 volts 44 amperes .

No . 2 i s a l 3o-wat t dynamo , 8 vol ts 55 amperes .

No . 3 i s a 200 -wat t equipmen t for large veh icles .

The commutators are of hard drawn Copper , i nsulatedwi th m ica ; the brush - holders

, of box type , contai nsquare brushes and ampl e sect ion .

Fig . 1 1 8 .

1 1 8 shows the swi tchboard , which is prov idedwi th vol t and amme ter

,and swi tches for the control

of each c i rcui t i t i s of po l i shed rosewood with h ingedmetal fron t .

The accumulators are constructed to withstandheavy charging and discharg ing . The pos i t ive platesare of the improved Plan te form ,

i n cel lulo id cel l s,the

whole being fi t ted in to teak boxes .

CHAPTER IX

HOT W IRE CONTROL L ED SYSTEMS

L ithanode — The standard vol tage adopted for usewi th the L i thanode dynamo (F ig . 1 1 9 ) i s 4 vol ts , i tbe ing claimed that th is vol tage i s qui te suffic ien t withproperly des igned lamps and bulbs

,with the addi t ional

advan tages tha t the fi laments of the lamp are strongerand las t longer, the set i s eas ier to i nstal , and that a

4- vol t battery i s easi l y obtainable anywhere in the

Fig . 1 1 9.

event of the cel l s breakingi

down ; short - c i rcui t ing isalso greatly m in im ised . But as a h igher candle - poweri s frequen tly cal led for, 8 and 1 2 vol t dynamos are al sosuppl ied these work on exact l y the same princ ipl e asthe 4 - vol t se t described .

The dynamo i tsel f i s of very s imple cons truct ion ,

cons ist i ng of an ord inary shun t wound machine wi ththe addi t ion of a s imple centri fugal cut - out, noti ceableon the left hand of the machine . This cut - out consis tss imply of two arms carry ing c i rcular weights

,kept i n

the normal pos i t ion by two springs (Fig. 1 20 ) when a tres t, thereby open ing the c i rcui t . When the dynamoattains suffic ient speed to generate (about R.P.

HOT WIRE CONTROLLED SYSTEMS 89

the weights fly out and two levers are pressed under. thel ive contact spring (Fig . 1 2 1 ) so that the c i rcu it i s closed .

Fig . 1 20 . Fig . 1 2 1 .

The weights themselves also complete the contact i npress ing against the brackets . The two levers and the

Fig . 1 22 .

con tac t spring form a rubbing con tac t,which keeps clean

even in the even t of any sparking tak ing place . In orderto preven t abnormal curren ts be ing generated at h igh

speeds,the curren t i s

l ed through a n ickelw i re res istance (Fig .

The res is tanceof n ickel w i re ri ses proport ional ly to the heati ng effect due to thecurren t

,so that when a

certain predeterm inedcurrent ( i n th is caseabou t 1 0 amperes ) i s

pass ing,the wi re gets hot and the consequent res i s t

ance i s suffic ien t to choke back any further rise incu rren t that would otherwise take place .

Fig . 1 23.


The hea t engendered in the wi re i s never suffic ientto cause danger from burn ing

,and the whole wire

frame is enclosed i n a perforated metal cover . An

i nc iden tal use for the res is tance i s to employ i t as a

Fig . 1 24. F ig . 1 25.

carriage warmer i n cold weather , and by fi tt ing a

second res istance outs ide the car and operat ing atwo -way swi tch , the res i stance heater i n the car. can

Fig . 1 26 . Fig . 1 27 .

be thrown out of act ion,the one outs ide the ca r

com ing i nto act ion i n warm weather.The swi tchboard (Fig . 1 23 ) for th is set comprises an

ammeter and voltmeter,also five swi tches control l ing

the two head,two side

,and tai l lamps ind iv idual ly .

HOT WIRE CONTROLLED SYSTEMS 9 1

The 4- vol t L i thanode battery is shown in F ig . 1 24 ,

and the se t of head,s ide , and tai l lamps in F igs . 1 25,

For use i n foggy weather , the makers supply anamber - coloured bulb which improves the l igh t whendriv ing through fog . This saves any al terat ion to

the lamps,as when the fog bulbs are not requ ired

the ord inary clear bulbs can be replaced .

It should be remarked tha t as the vol tage used in

Fig . 1 28 .

th is set i s low i n order to avoid res is tance and consequen t drop In vol tage

,spec ial heavy conductors a re

suppl ied by the make rs and these should be alwaysused to Ob tain sat isfactory resul ts .

Rushmore — The dynamo (F ig . 1 28 ) suppl ied .by

Messrs Rushmore depends upon the ac t ion of a hotwi re s im i larly to the las t machine described

,bu t the

appl icat ion is somewhat d i fferen t .The dynamo i tsel f fol lows standard l i nes except

that i t has a compound or d ifferen t ial co i l (bucking coi l )superimposed upon the ord inary shun t w i nd ing (Fig .


The iron wire res istance or bal last co i l (which iswound on an asbestos spool ) carry i ng the main curren thas both the term inals of the shunt and different ial co i l sconnected to i ts far end . The act ion is therefore asfol lows : A t low and moderately low speeds theshun t wind ing i s i n act ion and the d i fferent ial co il ,being small

,has pract ical ly no effect , therefore a

moderate current i s passed,sufficient to keep the

a ccumulators i n a proper state of charge . As soon ,

however,as the speed increases

,the curren t tends to

ri se,and pass ing through the

bal last co i l,heats i t and there LAMPS

fore throws a res istance i n c i rcu i t .The effect of th i s i s not only tochoke the main current but todrive curren t through the h i therto we"

almost i noperat ive d ifferent ial co i l “iii?which now beg i ns to act i n op

pos i t ion to the main Shunt,there

by weaken ing the main curren tand sett i ng up a state of balance .

Fig . 1 30 Shows very wel l thesudden r i se in res istance wh ich Fig . 1 29,

sets i n w i th heat ing at a certain

poin t of i ron wire A as compared wi th,say

,a german

si l ver res istance B.

By making the bal last co i l weaken the magnet i cfield through the d ifferent ial w ind ing

,cons iderable

energy is saved in dri v ing the dynamo,which

,were

the bal las t co i l used as a choking res i s tance alone ,would be rather wasteful . The dynamo begins togenerate current at about 200 R.P.M and gives i tsful l output 1 4 amperes at 600 the voltagesuppl ied be ing 6% vol ts .

The dynamo i n appearance is a s imple two- poleenclosed type wi th steel poles , the tips being combed



c i rculat ing through the cell s wh ich tends to keepthem in first- class cond i t ion . A s imple magne t i c

Fig . 1 32.Fig . 1 33 .

cut- out (F ig . I placed above the dynamo ,in terposed to break the ci rcu i t when the mach ine 15

Fig . 1 34.

a t rest . Two plain swi tches are prov ided on theswi tchboard : one controls the s ide and : tai l lamps

,

the other the head lamps , at the same t ime parallel ing

HOT WI RE CONTROLLED SYSTEMS 95

the ballas t coi l w i th the d ifferen t ial wind ing,and

a u tomat i cal ly increasing the dynamo ou tpu t to meetthe increased current used by the head lamps .

Figs . 1 3 2 , 3 3 , 1 34 show the head,

Side,and

tail lamps respec t ively . The reflec tors are of coppersu i tably s i lvered and of parabol ic design . The bulbsof the s ide lamps are a l i t tl e ou t of focus so as tothrow a scat tered ray .

The weigh t of the smal l dynamo,giv ing 1 5

amperes at 6 12vol ts

,i s 2 3 l bs . , and the large s ize

,

g i v ing 25 amperes at the same vol tage , i s 35 lbs .

G ENERAL L Y speaking the makers of l ight i ng sets are

conten t W i th supplyi ng the outfi t complete wi th the

F ig . 1 35.

head , s ide , and ta i l lamps,l eaving the accessories to

the customer’

s cho i ce , and we here propose to draw

Fig . 1 36 .

the reader’

s attent ion to a few'

of the more usefulfitments.

A s teering column lamp (Fig . 1 35) i s very usefulto read the various d ials of the vol tmeter and o i l and



Cigar l ighters are best avoided i f the purchaser canbring h imsel f to do wi thout th is luxury , as they alwaysburn out quickly

,and take a cons iderable amount of

current , bes ides which they wi l l not l ight a pipesat isfactori ly .

A good horn is a sine qua non , and any of thebetter class types on the market may be depended onto give Sat i sfact ion .

A word may be said here re the wi ring of i nteriorlamps by coachbu i lders

,as they should be careful ly

watched i n th is respect . Ins ist on proper cablesbeing i nstal led under the upholstery and not bel l wi rewh ich the maj ori ty of carriage bui lders seem to th ink

Fig . 1 40 .

suffic ient,the effi c ien t wi ring of a car being with them

quite subserv ien t to the effects of brocade and varn ish .

Shoddy bel l w i re and poor electri cal connect ions havebeen the making of many nas ty fires .

A l l w i res from the bodywork should be brought toa terminal board so that i f the body is removed i t wi l lno t be necessary to rewire the carriage work .

Spares.—The fol lowing spare parts should always

be carried1 . L ength of fuse wi re .

2 . Spare brushes .

3 . Set of bulbs .

"

4 . Bel t and one half- l i nk for Vee bel ts .

5. Cut- out contacts ( i f electrical ) .

CHAPTER X I

U PKEEP AND MAINTENANCE

IT should be ful ly real i sed that al l dynamo l igh t i ngse ts requi re a ttent ion i n the same way as acetyleneor o i l

,and that the . va rious componen ts of the se t

should from t ime to time be examined to see thatthey are in order .

Bearing S.

— F i rs t, wi th regard to the dynamo ,the

bearings mus t occas ional ly be o i led or greased i naccordance wi th the instruct ions issued wi th the set .The driv ing be l t , whether flat or “V ”shaped , shouldbe cleaned and t ightened i f necessary

,as a sl ipping

bel t i s often a cause of d im in ished ou tpu t .

Commutator. The brushes and commu ta torShould be exam ined to see they are not wearingunduly

,and any carbon dus t must be cleaned out of

the commu tator cover. Commu tators should be kep tclean and brigh t wi th a l i ttl e fine glass paper

,bu t

beyond th is the armature had bes t be re turned to themakers to be t ru ed up ; th is , however , should berarely necessary .

Contacts — Where the cut - out i s embod ied inthe mach ine i tsel f, the contact poin ts should rece iveatten tion i n case any burn ing of the con tact surfacehas taken place . If the cu t - ou t i s elec trical

,the con

tac t poi n ts should be exam ined to see they are clean

1 0 0 DYNAMO LIGHTING FOR MOTOR CARS

and unburned,and tha t the arma ture moves freely .

Contacts that have become burned or worn shouldbe touched up wi th a fine fi l e or emery paper, carebe ing taken no t to al ter the adj ustmen t , and to seethat the contact poin ts or brushes meet squarely . If

the cut - out i s of the free -wheel type see that i t worksfreely and that the lubricat ion is no t too th ick

,thereby

us ing more curren t than i s necessary to make thedynamo motorise .

Batteries.—Batter ies should rece ive weekly ex

amination , care being taken to ascertain tha t al lconnect ions are sound , and al l term inals free fromcorros ion . A l i ttle vasel ine should occas ional ly beappl ied to the term inals .

See that the tops Of the cel ls are free from ac idwhich may have been thrown off as spray fromprolonged charging , and see that the ac id is wel lover the tops of the plates . Examine the bottom of

the containers for any Sludge that may have beenthrown down and which is l ikely i n abnormal quan ti t iesto short - c i rcu i t the plates or at l east to cause leakageof curren t .

See that the cel ls are t ightly wedged in the i r boxso that they cannot shake about and break the i rconnect ions . Make sure the screws hold ing down thebox ( i f any ) are not loose . Somet imes i n comingunscrewed the heads work thei r way through thebottom of the cel lulo id cases .

After clean ing the battery,make sure the

'

prOper

l eads are replaced pos i t ive or red to the or redterm inal and negat ive or black to the or blackterm inal— th is i s most important : fai lure i n th is matterwil l i n many cases burn out the whole outfi t .

If the car is la id up for any considerable period forrepai rs , etc .

,the cel ls must be removed about once a


1 0 2 DYNAMO T L IG HTING FOR MOTOR CARS31

0flporcelaind isc for some l i ttl e d istance . The same

appl ies to the o ther end of the lamp lead where i tenters the pin plug i f these are used .

Sw itchboards.—l n the even t of i t being neces

sary to d i smoun t the swi tchboard , be careful to noteand mark the leads belonging to the various term inal s

,

so that when replac ing them no mistakes shal l bemade . In the even t of the ammeter or vol tme ters t i ck ing , the instruments Should be re turned to themakers as they are much too del i cate to be tamperedwi th by anyone no t used to the i r manufacture .

In the even t of the fuse blowing ,be careful to

replace wi th a piece of the correct fuse wi re , and no twi th a hai rp in or other unsu i table wire .

Before replac ing the fuse , the cause ( i f no ttemporary) of the short- c i rcui t should be ascertainedand the defect remed ied .

Searching for Faults— Fol lowing is a table of

l ikely defec ts and how to proceed to remedy them .

Remember i n search ing for faul ts to try one thing a ta t ime

,otherwise i t w i l l be d i fficul t to say what was

the defect,i f two parts of the system are in terfered

wi th a t the same t ime .

1 . A l l l ights go out suddenly . Probable cause ,

(a ) fuse blown, (é) battery connection broken , (e)

ba ttery l ug broken .

2 . Fuse blows or lamps go dul l when one se t of

lamps are swi tched on . Short - c i rcu i t i n e i ther thewi ring

,flexible leads

,or the bulb i tsel f.

3 . L amps grow d immer even when engine isturn ing fast . (a ) Pul ley sl ipping on engine shaft

,

(b) bel t sl ipping , (e) dynamo defec t ive , (a’

) cut - out not

working , (e) broken connect ion .

Ascer tain tha t the driv ing pul ley i s real ly qui te

UPKEEP AND MAINTENANCE 1 0 3

firm on shaft ; some t imes a pulley seem ingly fixedwi l l give when under load owing to engine v ibrat ion .

See that the bel t is suffi c ien t l y t ight ; i f i t i s Sl ippingthe ammeter needle wi l l general ly osc i l late v iolen tl y .

Exam ine dynamo and see that all appears i n order,tha t brushes are bearing fi rmly on the com . , and tha tthe cut - ou t i s real ly making con tact . Make surethere i s no break in the conductor between thedynamo and swi tchboard or between the board andthe battery .

4 . Dynamo fa i ls to generate . Same as No

(f ) broken field coil connect ions .

5. L amps wi l l not l igh t from the bat tery but l igh tvery brigh tly from the dynamo . (a ) Broken w i refrom the battery to swi tchboard , (é) battery fuseblown

, (5) lug or connec t ion broken in the ba tteryi tsel f

, (a’

) one or more cel l s empty of ac id .

6 . L amps grow dimmer when dynamo i s rotated a tcutt i ng- in speed

, (a ) broken field connect ion wherebyarmature only short - c i rcui ts the cel l s when cu t - in

works , (6) battery reversed .

G enera l Instructions — In the event of anyth inggoing wrong

,always see wha t i s the matter at once

,

o therwise extens ive damage may be done .

Short - c i rcui ts are general ly easy to locate byswi tch ing on one c i rcu i t at a t ime , firs t the s ide

,then

the head,and then the tail lamp ci rcu i ts . Before

j umping to a conclus ion try the bulbs in a d ifferen tholder which you know to be i n good order— it maybe that the bulb has only burnt ou t . A very troublesome short - c i rcu i t i s caused by the earth ing of oneonly of the conduc tors in each of two leads . Thus thenegat ive w ire of the head lamps may be earthed bychafing or o ther cause , and yet wi l l not show i t , as thecurren t has nowhere to flow to , hav ing reached earth .

1 9 4 DYNAMO LIGHTING FOR MOTOR CARS

The same may apply to the pos i t ive lead of, say ,the

s ide lamps wh ich wi l l burn qui te wel l as long as theyonly are al ight

,bu t the i ns tant the head and s ide

lamps are swi tched on together,the pos i t ive and

negat i ve leaks close the c i rcu i t through the earth or

frame and short - ci rcui t the battery , thereby blowingthe fuse . In th is even t there i s no thing to be donebu t careful ly exam ine the wiring of both doubtfulc i rcu i ts

,and i f noth ing can be found

, to completelyrewi re bo th , th is i s often the quickest i n the end .

If your l ights go ou t , a s imple way of test i ng forthe fuse , or part ial battery discharge

,i s to read the

vol tme ter, or to blow the electri c horn i f one is fi tted

to the car , as these fi tt ings are general ly connectedbefore the fuse .

Where a dual ign i t ion sys tem is connected to yourbatteries particular care should be taken to look out

for shorts , as the insulat ion on coil s and the l ike i sgeneral ly not up to the standa rd requi red by l igh t i ngequ ipment . Prolonged runn ing on the dual system

(general ly 4 vol ts ) should be avo ided as i t tends torun down two cel l s unduly , thereby leav ing the res t ofthe battery i n a h igher state of charge than the cel lsused . This also appl ies to 4 - vol t horns used on an 8or 1 2 vol t battery . In thi s event it

'

i s w ise to occasionally change the cell s over so that al l shal l ge t aneven discharge .

Somet imes i t wi l l be found ,owing to absence of

adj us tment or spares , that the bel t cannot be t igh tened .

A plan to get you home is to sprinkle the bel t withfull er’s earth or powdered res in . Th is should onlybe done as a last resource , and the res in should bescraped off as soon as poss ible , as i t tends to hardenthe bel t . Bel ts should be occas ional ly dressed wi thcastor or col lon o il to keep them supple and to excludemoisture . If the bel t i s not in good condition,

the


ACCUMULATORS,2,1 0 0

Acid,1 0 1

Armature, 2

BATTERY,2,1 0 0

Bearings, 99Belts

, 9

B leriot dynamo,6 1

Bosch dynamo, 7 2

Brolt dynamo, 48

Brushes,2

Bulbs, 5

C.A.V . DYNAMO, 40

Cells, 2,1 00

Centrifuga l governor, 25Clutch (Slipping) , 2 1

Commutators, 2, 99

Compound coil,2 2

, 6 2

Conductors,1 8

, 46

Contacts, 99Cut-outs, 23 , 24

B BC. DYNAMO,86

Earth , 1 7

Eisemann dynamo, 75

DASH LAMP I N SERI ES,20

D ifferentia l winding, 2 2

Doub le - insulated wiring system,

1 6

Drives for dynamo, 9Ducellier dynamo, 33Dynamos

B leriot, 6 1

Friction drive, 9

Bosch, 7 2

FUSG S,84 , 1 0 2

Brolt, 48

C ATV) 40 H OT WIRE RESISTANCES, 23 ,89 ,

Ducellier, 3 3 92

D EX

Dynamos (continued )86

Eisemann, 75

Facile, 7 1Leitner, 58Lithanode

,88

Lucas, 79

Magician, 56

M ira,26

Pape, 7 7Perfect

, 3 7

Peto Radford,8 1

Polkey—"arrott, 66

Rotax (Leitner), 50Rushmore

, 9 1

T . M.

, 3 7

FAC ILE DYNAMO, 7 1

Faults,1 0 2

Field magnets, 2

Fitting, 7Flat belt

, 9

Flexible leads,1 7

Fog bulbs, 9 1

INDEx m 7

INSTRUCTIONS, 1 0 3

Insu lation ,1 7 , 1 0 1

LAMPS, 4Leitner dynamo , 50Lithanode dynamo , 88

Lucas dynamo, 79

MAG IC IAN DYNAMO , 56

Mercury cut-out, 25

M ira dynamo,26

OUTPUT CURV ES, 39, 4 3 , 48 , SS,

63

PAPE DYNAMO , 7 7Perfect dynamo

, 3 7

Peto Radford dynamo,8 1

Plugs, 1 7

Polkey-"arrott dynamo , 66

Pul leys,1 0

R.A.C. CERTIFICATES, 3 1 , 4 7 , 7 1

Reaction (armature) , 2 2

Rotax dynamo, 50

Rushmore dynamo, 9 1

SHORT- C IRCU ITS,1 0 2

Single - insulated wiring system,

Spares, 98

Sw itchboard , 1 0 2

T . 81 M . DYNAMO , 3 7Tail lamp in series

,20

VARIABLE SPEED,20

V ee belt, 9

W IRIN G,1 6

,1 0 1

diagrams,

1 8,

1 9 , 20,

28, 3 2 1 34 7 3 8 , 4 L

P r in ted a t THE DARIEN PRESS,Edinbu rg h


ADVERTISEMENTS.

ADVERTISEMENTS. 6

THE PETO RADFORD

ELECTRIC L IG HTING SYSTEM

AUTOMOBILES.

DYNAMO

SWITOH BOARD.

COM PL ETE OUTFITS ,

CONSISTING OF

Dynamo w ith G overnor and Automatic Cutout,

Aluminium Sw itchboard w ith fuses and circuit. box ,

Battery of large capacity ,

Handsome set. of L amps, comp lete w ith bulbs a ndconnecting plugs.

SIDE LAMP.£ 2 7 1 0 O

WRITEFOR FUL L PRICEL /ST Please mention this advertisement when writing .

PETO 84 RADFORD, L TD.

12 Heddon Street, REGENTSTREET, LONDON,Teleplzone . Regent 2576 . Teleg rams . Concentration, Re

wg q L ondon.

Wo rk s ASH TEAD , SU RREY.

Th e Motorist seeking a sim p lesystem of Electric L ighting su it

a b le for the condition s m et w i tho n au tom ob iles , shou ld considerthe PETO RADFORD proposition . w h ich is very sim p le i ndeed .

The Dynam o is o f th e p la inshunt - w ound type , w ithou t

.

a nycom p lica ted opposed w ind ings o r

e lectrica l devices for Opposing the

effects of increa sed speed .

The m ach ine , constructed u ponw el l -know n principles, providesfor am p le ou tpu t , a t a m odera tespeed a nd tem pera ture , com b inedw ith silence in runn ing .

The necessity of m a inta iningconstant speed is provided for by

th e u se of a cleverly designed centrifu ga l lygovern ed pu l ley , m anufa ctu red by u s a s engineersto give no troub le and perform its functionsperfect ly .

The sim p l icity of the shunt-w ound dynam o ,

w e l l understood by every engineer o f the presentd ay , e l im ina tes d ifficu lties in handl ing th e m a

ch i nes , w h i lst the extrem e ca re w ith w hich everydeta i l ha s been ca refu l ly considered renders thisou tfit the M otor Ca r System p ar excel lence .

The PETO RADFORD System ha s beenselected and u sed on the ca rs of m any w e l l - know n

lead ing .au thorities in th e E lectrica l and Engineering W o rld , a s their know ledge h a s ena b ledthem to apprecia te its po ints and efficiency .

Th e com ponent pa rts , su ch a s sw itchboa rds,

sa fety fuses , connecting p lugs for lam p w ires,

m ethod of ru nn ing th e w ires a nd m aking g oodm echan ica l connections a t every po int , have beenw orked ou t w ith that th orou ghness w h ich isexpected from experienced Electrica l Enginee rsof 25 yea r s

’

sta nd ing .

7 ADVERTISEMENTS.

- R0 3 3 EA 0

) ,

OTOR CCESSORIESO S R A M B U L B S

LARGE AND VARIED STOCK KEPT.

Double contact) Double contact only

No . V o lt Apc

p r°x° Price No . V olt Appmx' Price.p . c.p .

7 1 12

OSRAM TUBU L AR ROOF L AMP BU L BS.

E V E R -R E A D Y A C C U M U L A T O R S'

ANY SIZ E. ANY CAPAC ITY

Ign .

No. V olt PriceH rs.

1 322 4 20 l 3 /6

1 323 4 40 l 9/6

1 324 4 60 25/

1 329 4 80 29/6

1 330 4 100 3 5/

I l lustrating No. 1 322. I l lustrating No. 1 324.

Write for Illustrated Catalogue ( P) g iving full particulars of these and many other

Specialities, to

THEEVER-READYWORKS, HerculesPlace, Holloway, London, N.


about the

(th e Perfect Ca r - l ighting Dynam o)

FACT SIMPL ESTMOST POWERFU L

MOST CERTA IN

CHEAPN ESS,COMPARED TO OTH ERS.

OUTPUT V AR I ABLE AT W I L L .

NO AUX I L I ARY DEV IC E .

N EV ER RU NS AS MOTOR .

FACT D ISCON N ECTS AUTOMATICALLY .

FACT 8 ALW AYS CHARG ES IN EXCESS OF

CONSUM PTI ON .

FACT 9 I NDESTRUCT IBLE BY ACC IDE NTAL SHORTC IRCU ITS.

SIM PLE AND ACCESSIBLE .

IT’S TH E ROCK I N G THAT DOES IT .

”

TW IL IG H T.

Limited4 5 -4 6 Po l a nd Street ,

L ONDON, W.C .

The peop le w ho gave y ou

L IG H T,

ADVERTISEMENTS. 1 0

The EISEMANNARMOUREI) M A G NETO

has a COMPLETE ARMOURING

OF ALUMINIUM and is AESO

L UTELY DAMP - PROOF The

only magneto that DOES NOT EVENSWEAT. Moreover, as no packing is

used, it is conveniently and EASILY‘TAKEN TO PIECES.

The EISEMANNG HT IN G DYNAM O

has a PERFECTED PRESSURECONTROL in addition to the ordinary

cut-in and cut-out. Its OUTPUTISO WATTS, or I2 volts and horn

6 to I5 amps. Its overall dimensions

IO by 5‘I‘ by 5} in. , and TOTAL

WEIGHT 34% lbs. For finish and per

fection of detail , p lease see the article itself.

L ondon Address

4 3 BERNERS STREET .

L ondon Manager STAN L EY ". WATSON .

A B C Code ,Telegrams

5th Edition. Rouu illon, Ox, L ondon.

”


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Dynamo Lighting for Motor Cars