Sunday, September 9, 2018

Useful Facts About Hipot Tester

By Paul Olson


High potential is normally abbreviated as hipot. It is a term used in reference to a specific form of electrical safety testing apparatus, called a hipot tester. These apparatuses are used to verify electrical insulation of finished appliances, cables and other devices composed of wires. Transformers, printed circuit boards, and electric motors are among such devices.

After a product/appliance has been manufactured or assembled, it is usually normal that there will be some level of current leakage. The amount of current leakage experienced is usually minimal and is caused by voltages and internal capacitance within the product. This leakage is normal and should be expected in every device. However, there are certain cases where excessive leakage current flow can occur due to various reasons.

Excess leakage may be caused by break down of insulation in the product, design flaws or many other causes. Such flaws usually lead to excessive current leaking and may cause electrical shock to anyone that comes in contact with the faulty product. The importance of a hipot test is to verify and ensure that the product is sufficiently insulated so as not to cause shock to the operator.

Dielectric Withstanding Voltage (DWV) is another term used in place of the term hipot test. This process involves application of a high voltage between the earth ground shielding and the conductor in the product that carry current. Exposure to excessive voltage causes resultant current flow through the product. A high potential tester is the gadget used in monitoring of this resultant current, which is also called leakage current.

This testing process makes one major assumption. The assumption is that if the insulation of the device is not broken by the deliberate application of excess voltage, then it should be safe for normal operation. The device should be able to withstand application of normal voltage, which is applied during normal use. The name Dielectric Withstanding Voltage comes from this assumption.

The test is aimed at stressing the insulator used in the appliance. Apart from stressing the insulator material, however, the test is additionally used to identify workmanship flaws in the product. The most critical monitored workmanship elements are minute spaces existing between the earth ground and current-carrying conductors. In ordinary environment of operation, shock, humidity, contaminants, shock, and dirt may fill these spaces.

The flow of current is allowed when the small gaps between earth ground and current-carrying conductors in electrical devices. This may cause a major electrical risk that must be rectified during manufacture before the product is made available on the market. Only DWV can be used for defect detection. Other methods may not be efficient like the DWV even though they can attempt to identify these defects.

A high potential tester is simply and electric device that manufacturers use to verify electrical insulation. It is comprised of a high-voltage source, current meter, and a switching matrix. The matrix is used to connect current meter and voltage source to all contact points in a cable. The testing process may be automated by the inclusion of a microcontroller and display.




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