Pres15 - Motmor Protection 2-02

7/29/2019 Pres15 - Motmor Protection 2-02

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2001 Cooper Bussmann, Inc.

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Motor and MotorCircuit Protection


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Motor and Motor CircuitProtection

Agenda

Motor Circuit Characteristics

Protection from Overcurrents Motor Circuit Requirements

Sizing OCPDs

Back-up Overload Protection

Type 2 Protection


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How does a motor operate?

Starting

Normally

What do we protect against?

Overload

Short-Circuit


5/70

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Motor InrushCurve

InrushCurrent

Normal

OperatingCurrent


6/70

300 %Overload

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes


7/70

ShortCircuit

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes


8/70 2001 Cooper Bussmann, Inc.

Motor CircuitRequirements(NEC)

430.101

Disconnecting means

430.52 Branch-Circuit Short-Circuit

430.32

Overload Protection

To Supply

M

Motor

Branch

Motor

Overload




NEC 430.102

Location(Of Disconnecting Means)

(A) In sight from Controller Branch-Circuit Short-Circuit Disconnect

(B) In sight from Motor

Branch-Circuit Short-Circuit Disconnect

Manual Motor Controller Suitable as Motor Disconnect Exceptions provided if (A) is lockable in open position.



Barrier, wall or islewith an obstruction

Lockable

Disconnecting

Means

1999 NECCode

Controller

M



In sight motordisconnecting meansrequired per 430.102(B)

Barrier, wall or islewith an obstruction

In sight (of controller)disconnecting means

ahead of controller

required per

430.102(A)

2002 NECCode Change

Controller

M




NEC 430.52

Branch-Circuit Short-Circuit Protection

(B) Must handle starting current

(C) Rating or Setting

(1) Table 430.52

Exception 1: Next Higher size is permitted if the values from

table 430.52 do not correspond to a standard size




Table 430.52 Maximum Rating

Non time-

delay

Fuse1

Dual-Element

(Time-Delay) Fuse

Instantaneous Trip

Breaker

Inverse

Time

Breaker

300% 175% 800% 250%

1Non-Time-Delay also applies toClass CC fuses




NEC 430.52(C)(1) Exception 2: If Motor Unable to Start, then size according to following:

Then Use Next Smaller Size .

400%300%225%400%

Inverse

Time

Breaker10

0A

Dual-Element

(Time-Delay) FuseNon time-

delay

Fuse1

300%

601-6000A

Fuse



Motor and Motor CircuitProtection NEC 430.32 (Overload Protection)

(a) More than 1 Horsepower.

(1) A separate overload device that is responsive to

motor current. This device shall be selected to trip orrated at no more than the following percent of the motornameplate full-load current rating.

Motors with a marked service factor 1.15 or greater -

125%

Motors with a marked temperature rise 40 C or less -125%

All other motors -

115%


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MOTOR CIRCUITDEVICES




What OCPD(s) can beused in a motor circuit?

Fuse

Circuit Breaker

MCP

Overload relay


18/70

1000

100

10

1

0.1

0.01

10100

10001

Timein

Seconds

Current in Amperes

Motor InrushCurve

1000


19/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

MCP at

minimum

setting

1000


20/70

Motor InrushCurve

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

MCP at

minimum

setting

1000


21/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

MCP at

maximum

setting

1000


22/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

Motor Inrush

Curve

MCP at

maximum

setting

1000


23/70

300 %

Overload

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

1000


24/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

MotorDamage

Curve

1000


25/70

MotorDamage

Curve

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

1000


26/70

MotorDamage

Curve

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MCP at

maximum

setting

1000


27/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

15A Circuit

Breaker

1000


28/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

Motor Inrush

Curve

15A Circuit

Breaker

1000


29/70

1000

100

10

1

0.1

0.01

10100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

15A Circuit

Breaker

1000


30/70

NON-2 Amp

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

1000


31/70

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Motor Inrush

Curve

NON-2 Amp

1000


32/70

Current in Amperes

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

NON-5 Amp

1000


33/70

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Motor Inrush

Curve

NON-5 Amp

1000


34/70

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

NON-5 Amp

1000


35/70

1000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Overload

Relay

1000


36/70

000

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Motor Inrush

Curve

Overload

Relay

1000


37/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

Overload

Relay

1000MCP t


38/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MCP at

maximum

setting

MotorDamage

Curve

Overload

Relay

1000


39/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

15A Circuit

Breaker

Overload

Relay

1000


40/70

Overload

Relay

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

NON-5 Amp

1000


41/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

FRN-R-1-6/10

1000


42/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Motor Inrush

Curve

FRN-R-1-6/10

1000


43/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

FRN-R-1-6/10

Motor and Motor Circuit


44/70



Optimal Branch Circuit Protection (Back-up OverloadProtection):

125% or up of FLA - FRN/FRS

130% or up of FLA- LPN/LPS

150% or up of FLA- LPJ

200% or up of FLA- LP-CC

1000


45/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

FRN-R-1-8/10

1000


46/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

MotorDamage

Curve

FRN-R-1-8/10

Overload

Relay

1000


47/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

300 %

Overload

MotorDamage

Curve

FRN-R-1-8/10

Overload

Relay


48/70


Single-Phasing

Single phasing is the opening of one phase of athree phase circuit.


49/70


Primary Single Phasing

Primary wire broken by:

Storm - Wind - Ice - Sleet - Hail - Lightning

Vehicle or Plane Striking Pole Falling Tree Limbs

Construction Mishaps

Primary wire burned out from short-circuit createdby animals(i.e. squirrel to ground)


50/70



Defective contacts on primary breaker - failure tomake up on all 3 poles.

Failure of 3 shot automatic reclosers to make upon all 3 poles.

Open pole on 3 auto. voltage tap changer

Open winding in one phase of transformer

Primary fuse open


51/70



Normal Condition

M

1.4 A

1.4 A

1.4 A

208V 1/3 HP Motor 40 C

F.L.A. = 1.4 Amperes


52/70



Single Phase Condition

M

1.61 A

3.22 A

1.61 A



(230%)

(115%)

Assume one phase lost on the primary side of transformer.

(115%)


53/70


Secondary Single Phasing

Damaged Motor Starter Contact - One Pole Open

Burned open overload relay (heater)

Damaged switch or circuit breaker on the main,feeder, or branch circuit.

Open fuse or open pole in breaker on main,feeder, or branch circuit.

Open cable or bus on secondary of transformerterminals


54/70



Open cable caused by overheated lug onsecondary side-connection to service head.

Open connection in wiring such as in motorjunction box (caused by vibration) or any pull box

Open winding in motor

Open winding in one phase of transformer winding


55/70



Normal Condition

M

1.4 A

1.4 A

1.4 A




56/70



Single Phase Condition

M

0 A

2.4 A

2.4 A



(173%)

(173%)

Contacts on one phase are worn out resulting in an open circuit

1000


57/70

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Secondary

SinglePhasing

MotorDamage

Curve

FRN-R-1-6/10

1000


58/70

Secondary

SinglePhasing

100

10

1

0.1

0.01

10 100 10001

Timein

Seconds

Current in Amperes

Overload

Relay

MotorDamage

Curve

FRN-R-1-8/10


59/70

What about shortcircuit protection for a

motor circuit?



60/70



Short Circuit Condition

CurrentSource M


61/70

If we size the overcurrentprotective device

according to NEC430.52 will we protect themotor circuit components

from a short circuit?


62/70

TYPE 1 PROTECTION

vs. TYPE 2PROTECTION

TYPE 1 vs. TYPE 2


63/70


TYPE 1 vs. TYPE 2PROTECTION

What is Type 1 and Type 2 Protection?

IEC 947-4-1 Standard

Type 1 Protection(Damage)

UL 508 Listing

Type 2 Protection(No Damage)

Type 2 Tables from Manufacturer

TYPE 1 vs. TYPE 2


64/70



Type 1 Protection:

Requires that, under short-circuit conditions, thecontactor or starter shall cause no danger to persons orinstallation and may not be suitable for further servicewithout repair and replacement of parts.

Similar to UL 508 requirements

TYPE 1 vs. TYPE 2


65/70



Type 2 Protection:

Requires that, under short-circuit conditions, thecontactor or starter shall cause no danger to persons orinstallation and shall be suitable for further use. Therisk of contact welding is recognized, in which case themanufacturer shall indicate the measure to be taken asregards the maintenance of the equipment.

T 2 P t ti T bl


66/70


Type 2 Protection Tables

TYPE 1 vs. TYPE 2


67/70



Does NEC require Type 2 protection?

TYPE 1 vs. TYPE 2


68/70



NEC section 110.10:

The overcurrent protective device, the total impedance,the component short-circuit current rating, and other

characteristics of the circuit to be protected shall beselected and coordinated to permit the circuit-protectivedevices used to clear a fault to do so without extensivedamage to the electrical components of thecircuitListed products applied in accordance with

their listing shall be considered to meet therequirements of this section.

TYPE 2 PROTECTION


69/70


TYPE 2 PROTECTION

Why Is Total Protection Important?

Maximum Safety To Personnel And Equipment

Minimum Cost To Stay In Service

Maximum Productivity From The Equipment



70/70


Overload Protection

Overload Relay

Fuses for Backup

Short Circuit Protection

Fuse, Circuit Breaker, MCP

Type 2 Protection(No Damage)

Documents

Pres15 - Motmor Protection 2-02