Control Wiring; Primary Circuit - ABB AMVAC Installation And Operation Manual

Medium voltage vacuum circuit breakers
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P
C
A
RIMARY
IRCUIT
To verify the integrity of the vacuum interrupters, perform the following low-frequency withstand voltage test:
1. Open the breaker (no control power supplied to breaker).
a. Connect the high potential lead to one terminal.
b. Ground the remaining 5 terminals and breaker frame.
2. Start machine with output potential at 0 (zero) VAC.
3. Increase the potential to the required voltage (see Table 3 on previous page).
4. Hold for one minute.
C
W
:
ONTROL
IRING
The control wiring requires visual inspection of hardware during routine maintenance. Disconnect control power before
verifying secondary hardware and before low-frequency withstand voltage testing.
Remove the front cover with a screwdriver. Correct any loose or missing mounting hardware. Verify the ground wire
connection to the frame and all connectors' alignment and snugness on the electrical components. Visually inspect the
secondary plug and correct any pins that may have become displaced.
To verify the integrity of the secondary insulation, perform the following low-frequency withstand voltage test:
1. Connect all pins from the secondary to a test wire
2. Connect test wire to the high potential lead of the test machine
3. Ground the breaker frame
4. Start machine with output potential at 0 (zero) VAC RMS.
5. Increase the potential to the required insulation test voltage (1125VAC RMS)
6. Hold for one minute
7. Reduce potential to 0 (zero) VAC and turn off machine
A successful withstand indicates satisfactory insulation strength of the secondary circuit. Failing insulation will not
sustain the voltage across the secondary. Replace the breaker control wiring if the insulation fails during low-frequency
withstand voltage testing.
Replace the front cover before operation. Verify the operation with 2-5 electrical operations in the Test position or with a
remote power supply.
22
:
SSEMBLY
(Pole)
1VAL050601-MB Rev C

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