14
4.14 SHUNT TRIP COIL
THERE MAY BE TWO SHUNT TRIP COILS INSTALLED ON A
BREAKER. BREAKERS EQUIPPED WITH A USD RELAY ARE FITTED WITH
A SHUNT TRIP COIL OPERATED EXCLUSIVELY BY THE RELAY. THIS
DEVICE IS A CYLINDRICAL SOLENOID MOUNTED BELOW THE TRIP
SHAFT BETWEEN THE LEFT AND RIGHT HAND MECHANISM
SIDEPLATES. THE SECOND, SHUNT TRIP -COIL IF NEEDED FOR
COMMON TRIPPING REOUIREMENTS IS MOUNTED ON THE OUTSIDE OF
THE LEFT HAND MECHANISM SIDE PLATE. IF A BREAKER IS EQUIPPED
WITH UNDERVOLTAGE TRIP DEVICE (NV) AS WELL AS SHUNT TRIP
COIL,THE "NV" OCCUPIES THE SHUNT TRIP COIL LOCATION WHILE THE
SHUNT TRIP COIL IS MOUNTED ON THE LOWER CROSS CHANNEL TO
THE LEFT OF THE "NV". EACH SHUNT TRIP COIL ACTS VERTICALLY ON
ITS OWN TRIP SHAFT LEVER. BECAUSE THE COILS ARE NOT
CONTINUOUSLY RATED, A NORMALLY OPEN AUXILIARY SWITCH
CONTACT IS WIRED IN SERIES WITH THE COIL TO OPEN THE TRIP
CIRCUIT WHEN THE BREAKER IS OPEN. AC OR DC POWERED COILS
WILL OPERATE TO TRIP AT APPROXIMATELY 50% OF RATED VOLTAGE.
THE NUMBER OF CONTACTS REOUIRED FOR VARIOUS INTERNAL
BREAKER CONTROL SCHEMES.
THE FOLLOWING CONTACT RATINGS APPLY:
10 AMPERES UP TO 254V A.C.
1 AMPERE AT 250V D.C.
2 AMPERES AT 125V D.C.
DUE TO SPACE LIMITATIONS, A DIFFERENT MODEL is USED FOR
20 POLE AUXILIARY SWITCHES, AND 12 POLE SWITCHES ON 14"
WIDE BREAKER. THESE SWITCHES ARE NOT RATED FOR D.C.
SWITCHING FUNCTIONS.
NORMALLY OPEN AUXILIARY SWITCH CONTACTS ARE IDENTIFIED
BY THE SYMBOL "a" ON THE WIRING DIAGRAM, NORMALLY CLOSED BY
4.1 6 CLOSING COIL (CC)
THIS DEVICE IS SUPPLIED ON ELECTRICALLY OPERATED CIRCUIT
BREAKERS AND CONSISTS OF A RECTANGULAR LAMINATED SOLENOID
FRAME MOUNTED WITHIN THE FRONT MECHANISM COMPARTMENT (FIG.
4.4.2, ITEM 8). ITS FUNCTION is THAT OF ROTATING THE CLOSE LATCH
THEREBY INITIATING THE CLOSING STROKE. IT MAY BE ENERGIZED BY
THE CLOSE BUTTON ON THE FACEPLATE OR BY A REMOTE CONTROL
DEVICE.
FOR THE CLOSING COIL TO BE OPERATIVE THE FOLLOWING
CONDITIONS MUST BE MET:
(A) BREAKER OPEN
(B) CLOSING SPRING FULLY CHARGED (SPRING LIMIT SWITCH CLOSED).
(C) TRIP LATCH AND LATCH ROLLER ENGAGED.
LATCH CHECKING SWITCH CLOSED. (REFER TO 4.20).
(D) ANTI-PUMP RELAY RESET. (IF PROVIDED REFER TO 5.3).
THE CLOSING COIL IS IDENTIFIED ON THE WIRING DIAGRAM BY THE
SYMBOL "CC".
4.17 CLOSING COIL LIMIT SWITCH AND ANTIPUMPING FEATURE
ALL ELECTRICALLY OPERATED BREAKERS ARE PROVIDED WITH AN
ANTIPUMPING FEATURE. ITS PURPOSE IS TO PREVENT REPEATED
CLOSING ATTEMPTS WHEN BREAKER IS TRIPPED WHILE THE CLOSING
CIRCUIT REMAINS ENERGIZED. (MAINTAINED AUTOMATIC CONTROL
CONTACT, ETC.).
FOR BREAKERS CONTROLLED BY LONG TIME OR
PERMANENTLY MAINTAINED CLOSE CONTACTS, THE OPTIONAL
ANTPUMP RELAY MUST BE USED. REFER TO SECTION 5.3 FOR
DETAILS.
THE STANDARD FEATURE, FOR BREAKERS CONTROLLED BY
MOMENTARY, OR SHORT-TIME MAINTAINED CLOSE CONTACTS AND
REOUIRING CLOSING SPRING CHARGING IN BREAKER OPEN
POSITION ONLY, DOES NOT INCORPORATE THE ANTIPUMP RELAY.
THE ANTIPUMPING FUNCTION IS PROVIDED BY THE CLOSE COIL
(CC) LIMIT SWITCHES LOCATED BELOW THE COIL (FIG. 4.4.2, ITEM 14).
WHEN THE COIL IS ENERGIZED, OR NORMALLY CLOSED "CC" SWITCH
CONTACT IN THE SPRING CHARGING MOTOR CIRCUIT OPENS AND
REMAINS OPEN UNTIL THE CLOSE COIL IS DE-ENERGIZED.
FIG. 4.14 SHUNT TRIP COILS
1. SHUNT TRIP COIL
2. USD RELAY TRIP COIL
4.15 AUXILIARY SWITCH
ON ALL H-3 UNITS A MULTI-SECTION ROTARY TYPE AUXILIARY
SWITCH CAN BE PROVIDED (FIG. 4.4. 1, ITEM 1 3). IT IS COUPLED
DIRECTLY TO THE CLOSING SHAFT AND OPERATES ON A SNAP-
ACTION PRINCIPLE WHICH PROVIDES QUICK BREAK SWITCHING. NO
AJUSTMENT IS REQUIRED AND THE SWITCH IS AVAILABLE IN THE
FOLLOWING CONTACT ARRANGEMENTS.
4 POLE, PROVIDING 2 NORMALLY OPEN AND 2 NORMALLY CLOSED.
8 POLE, PROVIDING 4 NORMALLY OPEN AND 4 NORMALLY CLOSED.
12 POLE, PROVIDING 6 NORMALLY OPEN AND 6 NORMALLY CLOSED.
16 POLE, PROVIDING 8 NORMALLY OPEN AND 8 NORMALLY CLOSED.
20 POLE, PROVIDING 10 NORMALLY OPEN AND10 NORMALLY CLOSED
NOTE THAT CONTACTS AVAILABLE FOR EXTERNAL USE WILL
BE REDUCED BY
THE SYMBOL "b".
