The insulation resistance testerunder UHV power can help many power workers conduct various power tests more conveniently.

What is a megohmmeter test?

A megohmmeter, also known as an insulation resistance meter, is a device used to test the insulation resistance of cables. The test conducted to understand the insulation resistance value is called a megohmmeter test.

What is the purpose of insulation resistance?

The motor winding wound inside the motor must provide a certain insulation resistance. This insulation is provided to resist high currents in the event of a short circuit. If a conductor has high insulation, its resistance to current will be higher. Similarly, if the provided insulation resistance is weak, it is more likely to cause damage to the equipment due to high current flow. Therefore, in order for any device to function properly, it should have high insulation resistance. Therefore, a megohmmeter insulation resistance test was conducted for this purpose.

Procedure for testing insulation resistance (IR)

The process of testing the IR value of motor windings involves the following steps. The windings of the motor are divided into red (R), blue (B), and yellow (Y), as well as body (in the absence of a neutral wire) or neutral wire (N). The following figure shows the appearance of the probe of the megohmmeter.

Step 1

Insert the measuring wire with a probe into the port of the megohmmeter. It has two ports, one for wiring and the other for grounding. In addition to these two, there is also a button used for insulation testing. The following figure shows how a megohmmeter performs IR testing.

Step 2

Connect one probe of the megohmmeter to the I, e (R) wires and the other to ground. Press the insulation test button after connection. Then, if there are no issues, the megohmmeter should indicate an infinite IR value. If it indicates zero, then we can conclude that IR cannot withstand high currents.

Step: 3

Repeat the process of connecting the probe to other lines I, e (B), and (Y). Check the IR value so that we know if the winding IR is good.