The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works.
Insulation resistance test 3 phase motor pdf.
Ground insulation test of a motor.
Motors are susceptible to the gradual failure of their insulation resistance.
The insulation resistance tester or megohmmeter generally known by its trade name megger can provide critical information regarding the condition of motor insulation.
Figure 3 typical scale on the megger insulation tester.
It is used to convert electrical energy into mechanical energy.
During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched.
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.
To measure the resistance in a three phase motor you will need a megohmmeter otherwise known as a megger.
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.
These motors run conveyor belts pumps fans and many other applications.
For tests we ll use megger mit 310.
In this video you will find out how to test 3 phase induction motor.
Induction motor no load test blocked rotor test vibration test temperature test phase sequence test insulation resistance test.
Reverse side of card at right is used to record the test data.
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.
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.
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.
We ll learn how to identify windings check windings.
Introduction the induction motor is one of the most important motors used in industrial applications.
Insulation resistance test insulation resistance failure of an electric motor is one of the first signs that the motor is about to fail.
Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor.
Figure 4 typical record of insulation resistance of a mill motor.
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.
Curve a shows test values as measured.
Loss of insulation resistance of an electric motor is one of the first signs of motor failure.
