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DC withstand voltage and leakage test

time:2020/10/21   source:华天电力  reading:453 time

The DC high voltage generator is mainly used for the DC withstand voltage and leakage test of zinc oxide arresters, cables, motors and other equipment. For the safety of people and equipment, the operator should follow the steps below:

⑴ Complete before load test. The voltage multiplier tube installed on the high-voltage shielded microampere to the high voltage outputs a high level, and supports the shielded wire dedicated microampere and the received test items.

⑵ Check whether the analytical instrument, discharge rod, pressure doubler, test product connecting wire, and grounding wire can be connected correctly. Whether the grounding wire connection is reliable and the high-voltage safety distance meets the requirements, the test can be started only if everything is normal.

Check that the instrument is normal. Turn on the single-phase AC 220V power switch. At this time, the green light is on, indicating that the power is turned on. Press the set button to enter the test setting interface before starting the DC leakage and DC withstand voltage test of the sample.

⑷Press the red button, red light, ON represents a high voltage, and high voltage is rising.

DC Hipot Tester.png

⑸ Gently adjust the coarse and fine adjustment of the potentiometer in a clockwise direction. The output end starts boosting from zero, and the boost reaction speed is preferably 3-5kV per second to increase a test working voltage. For large-capacity tests, a slow boost step is also given, which may cause voltage overshoot. It is also necessary to monitor that the charging current of the ammeter does not exceed the maximum charging current of the DC generator. When it rises to the required voltage or current. Record the readings of the ammeter and voltmeter at the specified time.

⑹ After the test design is completed. Step down, after coarse and fine adjustment of the voltage regulating potentiometer back to zero. Then press the green button to cut off the high voltage and turn off the power switch.

⑺ After the test is completed. Use the discharge rod to discharge the test sample many times. Only after the discharge can be close to the test product and wire removal work.

For small capacitor samples such as zinc oxide arresters, magnetic blown arresters, etc., first use a rough adjustment to increase to 90% of the required voltage (current). Then use the fine-tuning potentiometer to slowly increase the voltage to the required voltage (current) value. Then, read the voltage (current) value from the digital form. When the zinc oxide arrester needs to be measured at 75% VDC-1mA, the voltage value should be stopped when the current reaches 1mA (the voltage and current values can be recorded at this time). Then press the yellow button, the voltage drops to 75% of the original, and keep this state. At this time, the microammeter value and voltage value can be read. After the measurement, the potentiometer returns to the zero position counterclockwise. Press the green button and press the red button when you need to increase the pressure again.

When testing large capacitors, the boost should be developed more slowly. And it is necessary to monitor that the charging current of the ammeter does not exceed the maximum charging current of the generator. Be sure to slow down the boost speed to avoid excessive charging current. After the experiment is designed. Adjust the voltage through the potentiometer counterclockwise and return to the zero position. Then press the green button to cut off the high voltage. Note that when the voltmeter drops to a voltage of about 15kV, discharge with the discharge rod several times before continuing to ensure safety.

Be sure to read the instructions that come with the DC high voltage generator product carefully before operation. Operate strictly in accordance with the instructions to ensure the safety of personnel and equipment.

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