- Output voltage
- 0 to 5 kV AC on all models; 0 to 6 kV DC on LK7122+, LK7122U and LK9302
- Leakage ranges
- 0 to 12 mA AC and 0 to 5 mA DC; 0 to 999.9 µA AC or DC on LK7122U
- Insulation resistance
- 1 to 9999 MΩ at 100 to 1000 V DC on LK7122+, LK7122U and LK9302
- Test modes
- Withstand, insulation, withstand then insulation, insulation then withstand; LK7110+ and LK9302B run the withstand mode only
- Arc detection
- Nine sensitivity levels, for current steps caused by local flashover in the high-voltage loop
- Test time
- 0.1 to 999.9 s, ±(2% + 0.05 s)
- Display
- 16 character by 2 line backlit LCD with menu-guided operation
- Interfaces
- RS232 and PLC fitted as standard, SCPI command set for remote control and data collection
- Memory
- Ten storage locations numbered 0 to 9
- Body
- 280 × 100 × 370 mm, 10 kg
A hipot tester that only reports pass or fail tells you the insulation broke down somewhere above the limit. One that ramps to the voltage tells you where. This range is built around the second behaviour, with the ramp, the limits and the test sequence all set from a menu rather than by front-panel knobs.
Product overview
Five models share a 280 mm wide, 10 kg body, a two-line backlit LCD and the same four soft keys. They divide on two questions: whether a direct output is fitted, and whether insulation resistance can be measured. LK7110+ and LK9302B answer no to both; LK7122+, LK7122U and LK9302 answer yes.
The rear panel carries the mains selector, a fused inlet, a nine-pin PLC connector and an RS232 connector. Both interfaces are standard, which is unusual at this size and is the reason the range is specified into automated benches rather than only onto a manual one.
How the programmable hipot tester works
The operator sets a voltage, an upper and a lower leakage limit, a rise time and a test time. Starting the test ramps the output from zero to the set voltage over the rise time, holds it for the test time, and compares the leakage current with both limits throughout.
Exceeding the upper limit means the insulation broke down. Falling below the lower limit usually means the probe is not connected, which is why a floor is set as well as a ceiling. Either condition ends the test and drives the FAIL lamp and the audible tone.
Insulation resistance is a separate measurement at a direct voltage between 100 and 1000 V. The reading is taken after the charging current has decayed, which is why the accuracy figures are quoted separately above and below 500 V: at a lower test voltage the same insulation produces less current and the measurement is harder.
The four test modes decide what runs and in what order. W is the dielectric test, I is insulation, W-I runs dielectric first and insulation second, and I-W reverses them. The order matters when a dielectric test leaves charge on the item that would disturb the insulation reading.
How to select the right programmable hipot tester
Start with the output type. An alternating test alone is served by LK7110+ or LK9302B, which are the two models without a direct output and without insulation measurement. A product that has to be stressed in the blocking direction needs one of the other three.
The second question is the leakage range. Twelve milliamps covers appliances and assemblies; 999.9 microamps on LK7122U is for components whose good-state leakage is far below a milliamp, where a milliamp range would show almost nothing.
The third is the interface. All five carry RS232 and PLC, so the choice is not about whether remote control is possible but about which one the fixture uses. A bench built around SCPI commands uses the serial port; a fixture built around discrete signals uses the PLC connector.
The fourth is the sequence. If the product needs both tests in one program, the mode list decides: LK7110+ and LK9302B run the dielectric test only, while the other three can chain the two in either order.
Measurement limitations and selection considerations
The leakage reading includes the current through the fixture, the leads and the probe. On a low-leakage product that stray current can be a large part of the total, so the lower limit has to be set with the fixture connected, not from the product specification.
The insulation measurement is made at a direct voltage and read after a settling period. A highly capacitive item takes longer to settle than the test time allows, and the reading will drift during the hold; the test time has to be set with that in mind.
The arc detector watches for a fast current step. Its nine levels exist because a long-lead fixture is noisier than a short one, and a detector set too sensitively trips on the fixture rather than on the product.
Finally, the instrument holds a voltage and measures current. It does not measure the resistance of the protective bond, the power the product consumes or the temperature it reaches, and a product that needs those checks needs other instruments rather than a higher setting here.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
