Why do we Need to go on the Voltage Test?
View PDF | Print View
by: toriewuj9f
Total views: 12
Word Count: 429
Date: Sat, 31 Dec 2011 Time: 1:15 AM
The differences between DC voltage test and AC frequency voltage are as follows:
There're two kinds of voltage tests, i.e. DC voltage test and AC frequency voltage. The prosperities of insulating materials determine different Breakdown Mechanism between AC and DC voltage. There're a series of different media in most insulating materials and systems. When the equipment is working under AC voltage, the voltage will allocate itself in proportion to dielectric constant and size of the material. While the DC just locate the voltage in proportion to the material's resistance. If you want to do the DC voltage test, the test voltage of DC requires a higher degree than electrical safety tester.
Type test and factory test
Type test is used to judge that the insulation structure design is suitable for application. Usually after finishing the temperature test, humidity test, strife test and other tests, we should go on the test immediately. Generally we should switch on the voltage for one minute.
Factory test is to detect the defects of the products in the production process. It's not used to check the insulting structure design is reasonable or not. Usually we do the test for the finished products before packing. The insulation products usually have the following defects. The sharp components damage the wire insulation. The connecting ground cord or the primary and secondary electronic components is damaged by short circuit. The welding joint is off or bad manipulated. Or the creep distance is shortening. Or the insulation inside the transformer is damaged.
Voltage test and breakdown test
After voltage test, it only shows that the insulation structure of products can withstand the test voltage, but it doesn't mean that the product can withstand how much voltage. If we go on the application research of insulation material and the design of electric equipments, we need to test the dielectric strength, and we need to go on the breakdown test.
Breakdown test is to test the voltage when the dielectrics are broken down. When the electric field strength exceeds a certain limit, the current through the media and the voltage on the media won't suit to Ohm law, and they have a sudden increase. If the insulation breakdown for an electronic load product occurs, it loses the operation function operation. The result is completely different from the voltage test. Voltage test is to ensure that the products haven't any defects, and they can work safely and normally. As a result, the withstand voltage in voltage test is proven to be safe, reliable, effective, so we should be strictly follow it.
About the Author
I studied power supply for many years, manufactured electrical safety tester. Now focused on ac electronic load research.
