Toshiba HV6AS instruction manual Voltage, Page, Maintenance

Page 30 MAINTENANCE

CRITERIA:

1.If a current flow above 5 milliamperes is observed or if breakdown occurs, one or more of the interrupters has insufficient vacuum and must be replaced.

Exception: If the current exceeds 5 milliamperes the first time the voltage is brought up, reduce the voltage to zero and increase it again. It may be necessary to repeat this procedure a few times.

2.If the breaker fails to meet criteria 1, then repeat the test on each pole separately to identify the damaged interrupter or interrupters.

3.If the voltage can be held for 1 minute and the current flow does not exceed 5 milliamperes, the interrupter has a sufficient vacuum level.

After the test is complete, discharge any residual static charge from the primary terminals of the circuit breaker.

If a vacuum checker or AC hi-pot tester is not available, a DC hi potential test may be conducted. If a DC test is conducted, the test voltage must be increased to 31kV DC. The test duration for DC tests and the criteria for acceptance remain the same as for AC tests.

Fig. 35 Application of Test Voltage for Vacuum Check

22kV AC	1 minute
(31kV DC)
Voltage
Zero
15 sec	15 sec
	Time

WARNING

Do not use DC hi-pot testers which employ unfiltered half-wave rectifiers. The peak voltages produced by these testers may exceed the recommended value of 31kV. This can result in the production of harmful X- rays and may invalidate the test results.