This technical article introduces the withstand voltage knowledge and some related solutions.

High-voltage insulation test and breakdown test

Passing pressure test can only explain that the insulation structure of the product can withstand the test voltage, but cannot indicate how much it can take. If you need to measure insulating strength for research and electrical equipment designing, you need a breakdown test, which tests the dielectric pressure when it is broken-down.

Some customers request a minute test according to test standards, which is no good for the product: first, it may reduce the percent of pass of the products; second, it may damage part of the insulation structure and reduce product safety; third, it may damage some components, reduce the quality of the product and shorten its service life. Passing the test doesn't mean the lamps and lanterns are in good condition. In many cases, the LED lamp bead can pass the pressure test, but will cause the delay of lamps and lanterns, and will greatly destroy the life of the lamps and lanterns.

High-voltage insulation test methods:

1. Check it out whether its main power switch is "closed";

2. All electrically neutral metal parts besides some special design should touch the ground;

3. Connect all the wires at the power supply input of the tested instrument;

4. Close all of its power supply switch and relay, etc.

5. Make the test pressure of dielectric strength tester to 0;

6. Put its voltage output wire (usually red) to the power input end of tested equipment;

7. Put its return wire (usually black) to the touchable metal part without electricity of tested equipment;

8. Keep the pressure with appointed time;

9. Slow down the test pressure;

10. Cut the main power of the test equipment. Voltage output wire first and then the return wire.

Following situations mean the equipment fails the test:

1. When the test pressure cannot reach assigned one or the pressure is reduced;

2. When the dielectric strength tester indicate warning signal.

Special notes: 

1. Only the trained or authorized people can enter the test zone and operate the instrument;

2. Fixed and apparent warning slogan must be put around the test zone to prevent other people;

3. During the test, all the staff including operator must keep away from test instrument;

4. When the equipment is started, you are never allowed to touch its output line.

Improving methods: 

1. Add isolation transformer to effectively reduce its withstand voltage;

2. Increase the strength of insulation medium, such as glue or insulation spacer;

3. Improve the voltage endurance capability of circuit board: a. Choose the circuit board whose dielectric layer has good voltage withstand ability; b. Increase its creep distance.