Calibration method of withstand voltage tester_Common faults and troubleshooting of withstand voltage tester

　　Calibration method of withstand voltage tester

　　1. Tester output voltage

　　Figure 5 Output voltage calibration wiring diagram

　　Put the withstand voltage tester in the "reset" state, turn the "voltage adjustment" knob counterclockwise to the bottom, and connect the wires according to Figure 5. Press the "start" button, adjust the "voltage adjustment" button, so that the reading of the high-voltage meter is the value of the detection point shown in Table 3, and calculate whether the error between the indicated value and the reading of the high-voltage meter meets the technical indicators. If not, adjust the corresponding potentiometer value.

　　table 3

　　Note: Different output voltages should be selected with a suitable high-voltage meter’s measuring range. The error of the high-voltage meter should be within ±1.5%. If it is a pointer-type high-voltage meter, its measuring range should be above 1/3 of the scale.

　　2. Leakage current and alarm current

　　Figure 6 Leakage current and alarm current wiring diagram

　　Put the withstand voltage tester in the "reset" state, turn the "voltage adjustment" knob counterclockwise to the bottom, connect according to Figure 6, and set the "leakage current range" switch to 2mA. Select the corresponding load resistance according to Table 4.

　　Table 4

　　Common faults and troubleshooting methods of withstand voltage tester

　　1. No power indication when starting up, and the display is off

　　1. Please check whether the power supply is normal. If not, please check whether there is 220V and whether it is within the normal use range of the instrument;

　　2. Please check whether the fuse is damaged. If the fuse is damaged, please replace it with the same type of fuse;

　　3. Please check whether the power transformer has output. If there is no output, please replace the power transformer;

　　4. Please check whether the voltage regulator circuit 7812 is damaged. If it is damaged, please replace 7812.

　　2. Start-up alarm:

　　1. Please check whether the sampling resistor on the leakage current switch board is damaged. If damaged, please replace the sampling resistor of the corresponding gear;

　　2. Please check whether LM324 is damaged. If it is damaged, please replace LM324.

　　3. Voltage indication when power on

　　1. Please check whether the thyristor is damaged. If it is damaged, please replace it with the same specification thyristor;

　　2. Please check whether the optocoupler 3061 is damaged. If it is damaged, please replace 3061.

　　4. The machine is in test state when it is turned on

　　1. Please check whether NE556 is damaged. If it is damaged, please replace NE556.

　　2. Please check whether the start button is damaged. If it is damaged, please replace the start button.

　　5. Instrument startup, reset failure

　　1. Please check whether NE556 is damaged.

　　2. Please check whether the start and reset buttons are damaged. If they are damaged, please replace the start and reset buttons.

　　6. After turning on the machine and pressing the start button, the measuring light is on, but there is no voltage indication

　　1. Please check whether the high-voltage transformer is damaged. If it is damaged, please replace it.

　　2. Please check whether the voltmeter head is damaged. If it is damaged, please replace the voltmeter head.

　　7. No indication of leakage current

　　1. Please check whether the ammeter head is damaged. If it is damaged, please replace it.

　　2. Please check whether the 220Ω/5W resistor is damaged. If it is damaged, please replace it.

　　3. Please check whether LM324 is damaged. If it is damaged, please replace LM324.