An insulation resistance tester is a piece of test equipment, used to test insulation resistance between connections.
One use of the tester is to test three-phase AC induction motor stators.
A stator in a three-phase induction motor consists of three sets of tightly wound coils.
The coils are wound together and next to each other, and electrically separated by a layer of insulation on the copper wire.
Each copper winding has two ends.
As there are three sets of windings, that means there are six coil ends in total.
Each end is connected to form either a star or delta configuration.
For the induction motor to work, there needs to be a high level of electrical resistance between each of the three coils.
This is known as ‘insulation resistance’, and a tester is used to measure it.
An Insulation Resistance tester is used to check insulation resistance. Should be very high between Stator windings. pic.twitter.com/vizYjYKbyt
— Craig Miles (@acraigmiles) October 17, 2016