Vlf Hi Pot Test High Voltage Tester Low Frequency AC Hipot Tester
How does vlf hipot tester work
The VLF hipot tester (Very Low Frequency High Potential tester) is a type of high voltage test equipment used to test the integrity and insulation quality of electrical power cables, transformers, motors, and other electrical equipment. Here is how it works:
The VLF hipot tester generates a very low frequency AC voltage, typically around 0.1 Hz, which is applied to the equipment under test. The voltage output of the tester can range from a few kilovolts to several hundred kilovolts, depending on the application.
The low frequency of the VLF AC voltage has two major advantages over traditional DC high potential testing. First, it minimizes the risk of damage to the insulation of the equipment under test, which can occur with DC testing due to the presence of capacitive charging currents. Second, it is more effective in detecting insulation defects, including weak spots, voids, and moisture, which can be missed by DC testing.
During the test, the VLF AC voltage is applied to the equipment under test for a period of time, typically several minutes, while the leakage current is measured. The leakage current is a measure of the insulation quality of the equipment, and any significant increase in the leakage current during the test indicates the presence of a defect in the insulation.
VLF hipot tester parameter
| Type |
Output
Voltage/
Current |
Load Capacity |
Control Unit |
Booster |
Fuse
Tube |
Frequency/
Capacitance |
Dim.
(cm) |
Wt
(kg) |
Dim.
(cm) |
Wt
(kg) |
| VLF-30 |
30KV/20mA |
0.1Hz ≤ 1.1uF
0.05Hz ≤ 2.2uF
0.02Hz ≤ 5.5uF |
28× 37× 22 |
4 |
33× 18× 34 |
25 |
5A |
| VLF-40 |
40KV/30mA |
0.1Hz ≤ 1.1uF
0.05Hz ≤ 2.2uF
0.02Hz ≤ 5.5uF |
28× 37× 22 |
4 |
35× 20× 36 |
35 |
6A |
| VLF-50 |
50KV/40mA |
0.1Hz ≤ 1.1uF
0.05Hz ≤ 2.2uF
0.02Hz ≤ 5.5uF |
28× 37× 22 |
4 |
37× 24× 39 |
45 |
7A |
| VLF-60 |
60KV/50mA |
0.1Hz ≤ 1.1uF
0.05Hz ≤ 2.2uF
0.02Hz ≤ 5.5uF |
28× 37× 22 |
4 |
33× 18× 34
33× 18× 34 |
25+25 |
10A |
| VLF-70 |
70KV/55mA |
0.1 Hz, ≤ 0.5µ F
0.05Hz, ≤ 1.0µ F
0.02Hz, ≤ 2.5µ F |
28× 37× 22 |
4 |
33× 18× 34
35× 20× 36 |
25+35 |
10A |
| VLF-80 |
80KV/60mA |
0.1 Hz, ≤ 0.5µ F
0.05Hz, ≤ 1.0µ F
0.02Hz, ≤ 2.5µ F |
28× 37× 22 |
4 |
33× 18× 34
37× 24× 39 |
25+45 |
12A |
VLF hipot tester characteristic
Current, voltage and waveform data are all obtained directly by sampling from the high voltage side, so the data are real and accurate.
Over-voltage protection: When the output exceeds the set limit value, the instrument will shut down for protection, and the action time is less than 20 milliseconds.
Overcurrent protection: Designed as high and low voltage double protection, the high voltage side can be shut down precisely according to the set value.
The low voltage side will shut down when the current exceeds the rated current, and the action time is less than 20 milliseconds.
The high voltage output protection resistor is designed in the booster body, so there is no need to connect another protection resistor outside.
Due to the use of high and low voltage closed loop negative feedback control circuit, so the output is not capacitive rise effect.
Notes
- Power supply requirement: AC50Hz, 220V, stability of frequency: fluctuation less than 0.5%.
- When using it, the capacitance of the sample should not exceed the rated capacity of the instrument. The overlow capacitance of the sample will affect the output wave form. If the capacitance is less than 0.05µF, the instrument cannot output normally.
- When using it, it is prohibited to boost voltage without load, or to connect with resistive load.
More details for Vlf hipot tester
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