Toshiba HV6AS - Manual (Page 34)

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.
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.
Fig. 35 Application of Test Voltage for
Vacuum Check
1 minute
22kV AC
(31kV DC)
Voltage
Zero
15 sec 15 sec
Time
WARNING