Cutler-Hammer HWT-500, Инструкция по эксплуатации

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I.B. 35-557
16 of 45
INDIVIDUAL RELAY TEST
Westinghouse Electro-Mechanical Type CN-33, CNJ, BN. Before commencing work, refer
to the Safety Information.
These tests determine if the relays on a network protector breaker, CN-33 master relay, CNJ
phasing relay and the BN de-sensitizing relay are functioning properly and their setting in
regard to overvoltage close, reverse current trip, time delay and instantaneous trip, is
correct.
The test lead connection to the network relay terminals are made by backing out the
terminal screws which correspond to the relay contact structure until the second machined
head appears. This will permit the attachment of one of the alligator clip leads marked
“COMM-RED-GREEN” to the exposed end of the terminal screw. In the case of the type BN
relay, the front steel cover of the relay must be removed before the relay terminal screws are
accessible. When the relay terminal screw is backed out, the contact between the relay
terminal screw and the network protector breaker wiring is broken, but the contact between
the relay terminal screw and the internal wiring of the relay continues to remain intact.
Switch Positions
Network Protector open, breaker does not have to be in automatic mode.
FUNCTION Switch – “RELAY” position
I & PV Switch – PVA position
Supp VM Switch – CA position
PHASE switch – 0 position
Single PH Test Switch – OFF position
PHASING volt switch-ON position
SUPPLY Switch – 216 or 480 position depending on network system voltage
VARIAC – zero position
By increasing the VARIAC’S position, you can increase the in phase (zero degrees) overvoltage
phasing value to the desired overvoltage close value. The CN-33 relay overvoltage setting may be
adjusted through the use of a narrow blade screwdriver inserted in the overvoltage adjustment screw
located to the left side of the front bearing. Adjustment should be made until the red indicator light is
illuminated.
When making the CN-33 relay overvoltage close test on a 216-volt relay being used on a 480 volts
system the phasing voltage necessary to close the relay is not directly indicated on the Voltmeter.
The relay calibration on this system is determined by dividing the voltmeter reading by 2.2. However,
the suggested settings as listed in this manual are those that would be directly indicated by the
voltmeter.
The overvoltage setting of a CN-33 master relay must be made first since it is made by means of a
spiral spring fastened to the moving contact of the relay and will therefore affect the reverse current
setting of the relay. The BN de-sensitizing relay, BN dummy plate, or BN jack plate must be present
to complete the current coil circuits. This is necessary to provide the correct mutual impedance for
the CN-33 master relay phasing coils. The CN-33 master relay current and phasing coils are wound
on the same core.
A test voltage continuously variable from zero to fifteen volts is available for this test.