The most important thing in choosing a hipot tester is two indicators, the maximum output voltage value and the maximum alarm current value must be greater than the voltage value and alarm current value you need. Generally, the tested product standard specifies the applied high voltage value and the alarm judgment current value. If the applied voltage is higher and the alarm judgment current is larger, then the power of the step-up transformer of the hipot tester is required to be greater.
Generally, the power of the step-up transformer of the hipot tester is 3kVA, 5kVA, 10kVA, 10kVA, 100kVA, etc. The highest voltage can reach tens of thousands of volts. The maximum alarm current is 500mA-1000mA, etc. Therefore, you must pay attention to these two indicators when choosing a withstand voltage meter. If the power is too large, it will cause waste, and if the power is too small, the hipot tester cannot correctly judge whether it is qualified or not.
According to IEC414 or (GB6738-86), the power method of selecting the withstand voltage meter is considered to be more scientific. “First adjust the output voltage of ATO hipot tester to 50% of the specified value, and then connect the test object. When the observed voltage drop is less than 10% of the voltage value, the power of the hipot tester is considered sufficient. “That is, if the voltage value of the withstand voltage test of a product is 3000 volts, first adjust the output voltage of the hipot tester to 1500 volts and then connect the test object, if the value of the output voltage of the hipot tester is not greater than 150 volts, then the power of the withstand voltage meter is sufficient. There is a distributed capacitance between the live part of the test object and the casing. The capacitor has a CX capacitive reactance, and when an AC voltage is applied across the CX capacitor, a current will be induced.
The magnitude of this current is proportional to the capacity of the CX capacitor and the value of the applied voltage. When the current reaches or exceeds the maximum output current of the hipot tester, the test hipot tester cannot correctly judge whether the test is qualified or not.
Basic requirements
- Test voltage display – pointer or digital display
- Leakage current display – pointer or digital display
- Test time display – generally 0-99S
- Boost form – automatic or manual
- The breakdown alarm current can be set to full scale.
- Alarm form sound and light
- The error is generally within ±3%