How Magnetic Induction Lamps Work

8/18/2019 How Magnetic Induction Lamps Work

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How Magnetic Induction Lamps Work

By: L. Michael Roberts - CTO InduLux Technologies © 2008~2009 L. Michael Roberts - All Rights Reserved - May NOT be rerod!ced "itho!t er#issio$.

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How Magnetic Induction Lamps Work

odeless La#s'

t all o( the light sources currently in use ha&e one thing in common metal electrodes sealed into the "allsbulb en&elope/ to bring the electrical current inside the lamp chamber0en&elope.prisingly the main (ailure mechanisms in these typical lamps 2other than brea$age3 is:

4ailure o( the (ilament due to depletion o( the (ilament material o&er time as atoms are stripped o(( by theelectrical current5

6ibration "hich brea$s the (ilament especially "hen it is hot5

4ailure o( the seal integrity o( the lamp5 typically caused by thermal stresses in the area "here the electro

through the glass "alls. The (ailure o( the seal can either be sudden and complete or a 7slo" lea$8 o&erallo"ing the entry o( atmospheric gasses "hich contaminates the interior.

eam o( lighting in&entors has been to produce a lamp "ith no internal electrodes so as to eliminate theseon (ailure modes. In an electrodeless lamp the en&elope 2bulb3 is completely sealed and thus there is noospheric contamination due to seal (ailure and no electrodes to "ear out. On 9+ une ; patent ?@?A99 to co&er an early (orm o( Induction lamp.

electrodeless lamp the main (ailure mechanisms 2other than brea$age3 are:

epletion o( the mercury amalgam inside the en&elope 2bulb3. #hen the mercury ions are excited and bthe phosphors a small percentage o( them are absorbed by the phosphor coating o&er time.

4ailure o( the electronics 2ballast3 used to dri&e the lamp. This is not a catastrophic (ailure mode as typicelectronics 2ballast3 are external to the lamp and can easily be replaced.

" do you get an electrical current inside the lamp en&elope to excite the mercury ions

etic ($d!ctio$ La#s'

are t"o t"o o( induction lamps internal inductor lamps "here the induction coil is located inside a spheric

and external inductor lamps. Magnetic induction lamps are basically (luorescent lamps "ith electromagned around a part o( the tube or inserted inside the lamp. In external inductor lamps high (reDuency enerctronic ballast is sent through "ires "hich are "rapped in a coil around the (errite inductor on the outsidube creating a po"er(ul magnet.


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duction coil produces a &ery strong magnetic (ieldtra&els through the glass and excites the mercuryin the interior. The mercury atoms are pro&ided by

malgam a solid (orm o( mercury/. The excitedry atoms emit 16 light and Eust as in a (luorescent

he 16 light is up-con&erted to &isible light by thehor coating on the inside o( the tube. The glass( the lamp pre&ent the emission o( the 16 light asry glass bloc$s 16 radiation at the 9@+.F nm andm range.

duction lamp system can be considered as a types(ormer "here the inductor outside the glasspe is the primary coil "hile the mercury atoms inrt gas-(ill "ithin the en&elope0tube (orm a single-condary coil. The high (reDuency magnetic (ield

he inductor is coupled to the metallic mercury ions

g their electrons to reach an excited state.

the electrons re&ert to the ground state photons o( 16 light are emitted "hich excites the phosphor coatide "alls o( the lamp causing them to emit &isible light.

xternal inductor lamps ha&e the ad&antage that heat generated by the induction coil assemblies is externand can be easily dissipated by con&ention or conduction. The external inductor design lends itsel( to highelamp designs "hich can be rectangular or round.

's "ith con&entional (luorescent lamps &arying thecomposition o( the phosphors coated onto the insideinduction lamps allo"s (or models "ith di((erent colo

temperatures. The most common colour temperatuinduction lamps are +@,,) ?;,,) @,,,) and A@,,other colour temperatures and e&en coloured &ersioa&ailable.

Induction lamps reDuire a correctly matched electronballast (or proper operation. The ballast ta$es the inmains 'C &oltage 2or C &oltage in the case o( ;9 aballasts3 and recti(ies it to C. >olid state circuitry tcon&erts this C current to a &ery high (reDuency "hbet"een ;+, )!G and 9@, )!G in some models andbet"een 9.A@ and ;+.A M!G in other models dependthe lamp design.

This high (reDuency produced by the ballast is (ed to"rapped around the (errite core o( the inductor. The contain control circuitry "hich regulates the (reDuenccurrent to the induction coil to insure stable operatiolamp. In addition the ballasts ha&e a circuit "hich pa large 7start pulse8 at po"er-up to initially ioniGe the


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atoms and thereby start the lamp.

duction lamps do not start at ;,,H light output - they start at bet"een F@H and

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How Magnetic Induction Lamps Work