various cable testing methods. The choice of the right method and the most appropriate instrument Before moving on to the main hipot testing techniques, it is. that you understand the proper setup and use of our hi-pot testers. Please accepts pass results for the following four hi-pot test methods: AC VOLTAGE. Hipot testing involves using a high potential (voltage) to test insulation. A hipot test can be very useful in helping you develop a process that builds high quality.
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DC voltage is applied to open disconnected windings by the Hipot tester or motor analyzer. The DC voltage potential in the windings is rapidly raised to a predetermined level, or raised in steps up to this level, depending on what test method is used.
As the voltage is raised, several currents will flow into and possibly out of the windings to ground, and the procedurs total of these currents are measured by the Hipot tester. The currents are the same currents present in an insulation resistance test:.
How DC Hipot Tests Work
Sometimes the question becomes, which is it, dirt or weak insulation? To learn more hiopt the Hipot Step Voltage Test page. The peak value of this current may be very high, reflecting the energy stored in the capacitance of the winding.
Normally, this current cannot be accurately measured. High direct voltage also referred to as over-voltage: Electrical insulation failure or breakdown is usually indicated by an arc, a sharp capacitive discharge, at the failure location.
DC Hipot Tester – Hipot Test Procedure – Electrom Instruments
There are times when failure or partial failure is indicated by a large abnormal change in the measured current or by erratic behavior of the measured current. Get a Quote Careers Exhibitions. January 17, by shawn. The currents are the same procedhre present in an insulation resistance test: This is also called inrush current.
The windings have capacitance.
Current is required to elevate its voltage potential. This current typically drops to zero within seconds after the test voltage provided by the motor tester is stable. I A — Absorption current: This current is present during the atomic and any molecular polarization of the insulation, and is the current one is interested in during a Procedurf test.
This current will drop to zero, or near zero, over hlpot period of time that varies by motor. It can happen in seconds or may take 10 minutes or more. I G — Volume Conduction current: This is the current that flows through the entire volume of the insulation between ground and the conductors. In good windings, this current is usually zero or near zero, and depends on the composition and condition of the insulation system. I L — Surface conduction current: This is often referred to as surface leakage current.
The surface conduction current runs over tewt end winding surfaces of the insulation. It is a result of surface contamination, dirt and moisture on the windings that are connected to ground.
As the contamination level increases, the resistance of the contamination drops, and the current increases. As the voltage increases, the current proceudre more or less proportionally with the voltage applied by the motor tester.
Hipot – Wikipedia
For used, good motors, this current will dwarf the absorption and volume conduction currents because of the relatively lower resistance in the surface procddure. For new, totally clean, and dry motors this current should be zero or near zero. Currents as a function of time during a DC Hipot test.