By hvhipot 
Is a VLF Hipot Tester a device capable of generating extremely low frequency signals? Its frequency range is usually below a few hertz, far below the audible range, and can even reach frequencies of tens of millihertz or lower. However, VLF Hipot Testers may malfunction during long-term use. The following are common faults and solutions for VLF Hipot Testers:
1、The digital display does not light up after the power is turned on
Check the power connection and fuse. If the fuse is damaged, replace it with a fuse of the same specification.
2、The high voltage display light is not on and high voltage cannot be applied
1. Return to zero problem
When there is no return to zero position, please turn the high voltage output adjustment knob and fine adjustment knob counterclockwise to return to zero position until the “return to zero” light goes out, then high voltage can be added.
2. Grounding wire issue
The grounding wire is not properly connected. Check the grounding wire and restart the equipment.
3. Cable connection issues
The cable connecting the control box and the high-voltage tower is not properly connected. Please reconnect the cable and restart.
4. Soldering and disconnection issues
One of the wire ends inside the control box has detached and broken, re weld and restart.
3、Trigger protection before reaching rated voltage
1. Overcurrent problem
Short circuit or excessive leakage current, rapid voltage rise when loaded with large capacitors. Restart and slow down the boost speed.
2. Overvoltage issue
The overvoltage protection setting knob is not in place. Please rotate it clockwise everywhere and restart.
4、Short circuit occurs under high voltage of the test sample
Due to the high short-circuit current, it is possible to turn on all fault display lights, which is normal. Restart after troubleshooting the test sample.
5、After troubleshooting the sample, high voltage still cannot be applied
After troubleshooting the sample, the fault display light still lights up and high voltage cannot be applied. At this point, restarting the device will increase the voltage.
6、The digital fluctuation of the voltmeter is large
Check if the shielding wire ends and the central shielding wire end of the connecting cable are disconnected or detached. If they are disconnected, please weld them properly.
7、Other precautions
1. Preparation before the experiment
Before the experiment, the test sample should be fully discharged with a discharge rod.
2. Interrupt handling
If interruption is required during the boosting process, do not directly turn off the power. You can use the shutdown button and discharge the test sample fully with a discharge rod before turning off the power.
3. Discharge operation
When using a discharge rod, it is necessary to first discharge the current end with a limiting current.
4. Voltage and frequency setting
Set corresponding voltage and frequency according to different cable voltage levels.
In short, common faults in VLF Hipot Testers can be solved by carefully inspecting the power supply wiring, fuse, grounding wire, cable connections, and internal wiring of the control box. During use, it is important to strictly follow the instructions to avoid equipment damage caused by improper operation.