Insulation Resistance Test 3 Phase Motor Pdf

The insulation resistance tester or megohmmeter generally known by its trade name megger can provide critical information regarding the condition of motor insulation.

Insulation resistance test 3 phase motor pdf.

To measure the resistance in a three phase motor you will need a megohmmeter otherwise known as a megger. Loss of insulation resistance of an electric motor is one of the first signs of motor failure. Induction motor no load test blocked rotor test vibration test temperature test phase sequence test insulation resistance test. 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.

These motors run conveyor belts pumps fans and many other applications. 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. 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. Insulation resistance test insulation resistance failure of an electric motor is one of the first signs that the motor is about to fail.

The primary causes of insulation. In this video you will find out how to test 3 phase induction motor. The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works. 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. Curve a shows test values as measured. 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. Introduction the induction motor is one of the most important motors used in industrial applications.

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. Curve b shows same values corrected to 20 c see page 22 giving a definite downward trend toward an unsafe condition. Figure 3 typical scale on the megger insulation tester. Motors are susceptible to the gradual failure of their insulation resistance.

We ll learn how to identify windings check windings. For tests we ll use megger mit 310. During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched. It is used to convert electrical energy into mechanical energy.

Figure 4 typical record of insulation resistance of a mill motor.