The so-called withstand voltage tester, according to its function, can be called electrical insulation strength tester, dielectric strength tester, etc. Its working principle is: apply a voltage higher than the normal working voltage to the insulator of the tested equipment for a specified period of time, and the voltage applied on it will only produce a small leakage current, so the insulation is better. The test system consists of three modules: programmable power supply module, signal acquisition and conditioning module and computer control system. Select two indicators of the voltage tester: large output voltage value and large alarm current value.
Wiring method of withstand voltage tester:
1. Check and confirm that the main power switch of the withstand voltage tester is in the “off” position
2. Except for the special design of the instrument, all uncharged metal parts must be reliably grounded
3. Connect the wires or terminals of all power input terminals of the equipment under test
4. Close all power switches and relays of the tested equipment
5. Adjust the test voltage of the withstand voltage tester to zero
6. Connect the high voltage output line (usually red) of the withstand voltage tester to the power input terminal of the equipment under test
7. Connect the circuit grounding wire (usually black) of the withstand voltage tester to the accessible uncharged metal part of the equipment under test
8. Close the main power switch of the withstand voltage tester and slowly increase the secondary voltage of the tester to the required value. Generally, the boosting speed shall not exceed 500 V / sec
9. Maintain the test voltage for a specified period of time
10. Slow down the test voltage
11. Turn off the main power switch of the withstand voltage tester. First disconnect the high voltage output line of the withstand voltage tester, and then disconnect the circuit ground wire of the withstand voltage tester
The following conditions indicate that the tested equipment cannot pass the test:
*When the test voltage cannot rise to the specified voltage value or the voltage drops instead
*When a warning signal appears on the withstand voltage tester
It should be noted that due to the dangerous high voltage in the withstand voltage test, special care must be taken during the test.
The following points need special attention:
*It must be specified that only trained and authorized personnel can enter the test area to operate the instrument
*Fixed and obvious warning signs must be placed around the test area to prevent other personnel from entering the dangerous area
*When testing, all personnel, including the operator, must stay away from the testing instrument and the equipment under test
*Do not touch the output line of the test instrument when it is started
Test steps of withstand voltage tester:
1. Check whether the “voltage regulation” knob of the withstand voltage tester is rotated to the end anticlockwise. If not, rotate it to the end.
2. Plug in the power cord of the instrument and turn on the power switch of the instrument.
3. Select the appropriate voltage range: set the voltage range switch to the “5kV” position.
4. Select the appropriate AC / DC voltage measurement gear: set the “AC / DC” switch to the “AC” position.
5. Select the appropriate leakage current range: set the leakage current range switch to the “2mA” position.
6, preset leakage current value: press the “leakage current preset switch”, set it in the “preset” position, then adjust the “leakage current preset” potentiometer, and the current value of the leakage current meter is “1.500″ mA. to adjust and switch the switch up to “test” position.
7. Timing time setting: set the “timing / manual” switch to the “timing” position, adjust the timing dial switch and set it to “30″ seconds.
8. Insert the high voltage test rod into the AC voltage output terminal of the instrument, and connect the hook of the other black wire with the black terminal (ground terminal) of the instrument.
9. Connect the high-voltage test rod, ground wire and the tested equipment (if the instrument is being tested, the general connection method is: connect the black clip (ground end) to the ground end of the power cord plug of the tested object, and connect the high-voltage end to the other end of the plug (L or n). Pay attention to the measured parts should be placed on the insulated worktable.
10. Start the test after checking the instrument setting and connection.
11. Press the “start” switch of the instrument, slowly adjust the “voltage regulation” knob to start the voltage rise, and observe the voltage value on the voltmeter to “3.00″ kV. At this time, the current value on the leakage current meter is also rising. If the leakage current value exceeds the set value (1.5mA) during the voltage rise, the instrument will automatically alarm and cut off the output voltage, indicating that the measured part is unqualified, Press the “reset” switch to return the instrument to its original state. If the leakage current does not exceed the set value, the instrument will reset automatically after the timing time, indicating that the measured part is qualified.
12.Use the “remote control test” method: insert the five core aviation plug on the remote control test rod into the “remote control” test end on the instrument, and press the switch (to be pressed) on the test rod to start. Aviation plug, also known as plug socket, is widely used in various electrical circuits and plays the role of connecting or disconnecting circuits.
Post time: May-07-2021
