In an electric device, the high quality of insulation is an important factor. There will be alters in the insulation building of electrical tools according to particular factors like environmental conditions, temperature, time, etc. Therefore we require to inspect the insulation resistance top quality at consistent intervals so the we deserve to avoid electrical shock. A megger is supplied to examine the insulation resistance the the electric equipment. So we can use a megger to test a motor, generator winding, cable, etc. A megger tests a cable by applying a high voltage DC to it because that a certain time duration so that the insulation quality have the right to be determined. A megger is comprised of a DC generator and also an Ohm meter.

How to use a megger to check a three-phase motor


Before weuse a megger for testing we need to check specific factors

The leads in the megger should be confirm for any kind of faults. And also the leads should have electrical continuity.To check the electric continuity of a megger we must attach both the leads together while the megger is ONCheck the dress wiring of the maker which is to be measuredMake sure that all the relations are complete before testing.

Check the three-phase engine is connected to delta or not, if so remove the links.

Windingresistance test of the motor

The first step would be checking the winding resistance. So favor the multimeter a megger would additionally have a rotary selector so revolve it to Ohms and also after the check, the leads and also this will certainly be checking electrical continuity. Connect the probe to the motor to inspect the winding resistance from step to step terminal. So we must examine the two ends that the first, second, and third winding, in stimulate to execute this connect the probe come the very first winding and check its 2 ends with the various other probe and do the exact same for second and third winding. If doing this we must switch top top the megger testing. Throughout this experimentation all the windings must display high and practically equal value then the motor is ok.

Insulationresistance test of the motor

In stimulate to execute this experimentation change, the megger setup to voltage and the voltage level have to be collection greater than 250V. Connect one probe of the megger come the earth connection in the motor. So insulation resistance to earth can be confirm then attach the 2nd probe come the first winding and also check the value, then do it for the second and third, and also if all the worths are virtually the same then its ok. Then examine the insulation resistance between the windings.

While check the insulation resistance the the motor the values will be practically the same for the 3 windings if therefore the motor is ok and if the probes are connected to the exact same winding climate the meter will display zero.

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So if all the readings are practically the same and high for the insulation and also winding test of the motor then the engine is ok.