Regular checks of motor insulation resistance the key to prolonging the life of any electrical device is periodic checks maintenance the insulation resistance of stored and active motors should be checked regularly.
Insulation resistance test 3 phase motor pdf.
The primary causes of insulation.
Curve a shows test values as measured.
In an industrial facility the recommended procedure is to perform periodic tests and record the results so damaging trends can be detected and corrected to prevent an outage.
To measure the resistance in a three phase motor you will need a megohmmeter otherwise known as a megger.
We ll learn how to identify windings check windings.
Curve b shows same values corrected to 20 c see page 22 giving a definite downward trend toward an unsafe condition.
Unlike an ohmmeter a megger can measure high voltage resistance values which are generally the kinds of values you will encounter with three phase motors.
These motors run conveyor belts pumps fans and many other applications.
Induction motor no load test blocked rotor test vibration test temperature test phase sequence test insulation resistance test.
Loss of insulation resistance of an electric motor is one of the first signs of motor failure.
A if the insulation resistance of a new cleaned or repaired motor that has been stored for some time is less then 10 mω the reason might be that the windings are humid and.
For a three phase motor the isolation resistance can usually be measured between each motor winding or phase and between each motor stage and motor frame earth by an insulation tester or megger 4.
For a three phase motor insulation resistance is usually measured between each motor winding or phase and between each motor phase and motor frame earth using an insulation tester or megger.
Introduction the induction motor is one of the most important motors used in industrial applications.
It is used to convert electrical energy into mechanical energy.
Insulation resistance test insulation resistance failure of an electric motor is one of the first signs that the motor is about to fail.
During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched.
Motors are susceptible to the gradual failure of their insulation resistance.
In this video you will find out how to test 3 phase induction motor.
For tests we ll use megger mit 310.
The insulation resistance tester or megohmmeter generally known by its trade name megger can provide critical information regarding the condition of motor insulation.
Reverse side of card at right is used to record the test data.
Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor.
Three phase dual voltage motor insulation resistance testing three phase dual voltage motors are used for most day to day operations in today s industrial plants.
Figure 4 typical record of insulation resistance of a mill motor.
