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12 – 7
12.8
Mechanism Operated Contacts (MOC)
The circuit breaker may be equipped with an external auxiliary switch assembly. These external auxiliary switches are known as
Mechanism Operated Contacts. In short, the assembly is also referred to as the MOC.
The MOC assembly is mounted within the circuit breaker compartment (cradle) and is connected to the main breaker-driveshaft
via a coupler, which is added to the circuit breaker during the MOC installation.
The circuit breaker, itself, may be optionally ordered with either no internal auxiliary switches, a set of four internal auxiliary
switches (2
a
+ 2
b
contacts), or eight internal auxiliary switches (4
a
+ 4
b
contacts).
With the addition of a MOC device, an additional eight auxiliary switches (4
a
+ 4
b
contacts) may be added to a circuit breaker.
Note referencing ANSI C37.100:
“a” contact: A secondary contact that is open when the circuit breaker is open, and closed when the circuit breaker is closed
“b” contact: A secondary contact that is closed when the circuit breaker is open, and open when the circuit breaker is closed
(1)
Fixed-mounted circuit breaker
(2)
Cradle
(1)
MOC
(2)
4 signaling switches
(3)
Driver for connected position
(4)
Driver for test position
(5)
Warning label
0757_nu
(1)
(2)
S50
S51
S52
S53
a
3
4
b
1
2
a
3
4
b
1
2
a
3
4
b
1
2
a
3
4
b
1
2
Attention: Four
contact
blocks must be installed
for proper operation
Attention: Four
contact
blocks must be installed
for proper operation
(1)
(2)
(3)
(4)
(5)
Summary of Contents for UL 489
Page 36: ...5 21 Frame size II 3000 A Frame size III 1 Holes 14 mm 0720 1 0721_nu ...
Page 63: ...7 2 Horizontal connectors 0733_nu top view ...
Page 64: ...7 3 Rear vertical connectors 0734_nu top view rear view ...
Page 65: ...7 4 Front connectors 0736_nu front view top view ...
Page 66: ...7 5 Front connectors and pressure wire terminals 0737_nu top view front view ...
Page 67: ...7 6 7 2 Frame size II fixed mounted version 0494 3_nu ...
Page 68: ...7 7 Class C always 0494 5_nu top view rear view ...
Page 69: ...7 8 2500 0738_nu LH side view front view ...
Page 71: ...7 10 7 4 Frame size III fixed mounted version 0495 1_nu LH side view ...
Page 72: ...7 11 0495 2_nu top view top view ...
Page 73: ...7 12 0495 3_nu top view rear view ...
Page 75: ...7 14 7 5 Door cut outs fixed mounted circuit breaker Frame size I 0735_nu ...
Page 76: ...7 15 Frame size II III 0496_nu ...
Page 77: ...7 16 7 6 Frame size I draw out version 0745_nu ...
Page 78: ...7 17 0746_nu rear view top view ...
Page 79: ...7 18 0747_nu bottom view ...
Page 80: ...7 19 0748_nu ...
Page 81: ...7 20 0749_nu ...
Page 82: ...7 21 7 7 Frame size II draw out version 0490 1_ul ...
Page 86: ...7 25 7 8 Frame size III draw out version ...
Page 87: ...7 26 ...
Page 88: ...7 27 ...
Page 89: ...7 28 7 9 Door cut outs for draw out circuit breakers Frame size I 0750_nu ...
Page 91: ...7 30 7 11 External sensor for neutral conductor WLNCT2 ...
Page 92: ...7 31 WLNCT3 ...
Page 107: ...9 5 I tripping Ground fault tripping ...
Page 351: ......