Toshiba offers a compact vacuum checker (Type CI35-1D, see Figure 22) which enables a quick and easy check on vacuum interrupter internal pressure. Alternatively, any commercially available AC high potential tester may be used which is capable of delivering at least 25 milliamperes at 22 kV for a period of one minute.
Figure 22 Toshiba Portable Vacuum Checker
PRECAUTIONS:
Applying abnormally high voltage across a pair of contacts in vacuum may produce X-rays. The radiation may increase with the increase in voltage and/or decrease in contact spacing. X-radiation produced during this test with recommended voltage and normal contact spacing is extremely low and well below the maximum permitted by standards. As an additional safety measure, it is recommended that all personnel keep at least 1 meter (3.3 ft) away from the vacuum circuit breaker while this test is performed.
Radiation exposure hazard. X-rays may cause illness or injury. Stay at least 1 meter (3.3 ft) away from the circuit breaker during the vacuum check test .
Hazardous voltages are present during dielectric testing which can result in severe injury or death. Only qualified personnel should conduct this testing.
See Figure 23 for sample withstand voltage test circuit.
Figure 23 Sample Withstand Voltage Test Circuit
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WARNING
WARNING