Electric Motor Winding Tester

The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works.

Electric motor winding tester.

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. You may find that when it runs ungrounded that the casing becomes live at up to supply voltage. The most common failure mode of a 3 phase ac motor is burnt winding or shorted winding leading to the damage of the motor. If windings are shorted together the electro magnetic fields cannot be created for that coil causing the motor to run erratically or fail all together.

Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor. Technicians should perform a series of tests on an electric motor during routine preventive maintenance or before replacing it. Bearing problems may be the number one cause of electric motor failure but electrical faults are a close second. Ac motor winding resistance test check the motor winding resistance or ohms reading using a multimeter or ohmmeter for phase to phase terminal u to v v to w w to u the ohms reading for each winding must be the same or nearly the same.

Ground insulation test of a motor. Test t1 to t2 t2 to t3 and t1 to t3. Test electric motor windings when a bad motor winding cannot be found by a physical inspection many times an ohmmeter may show that there is a defective winding. While testing make sure the leads on each end are not touching other leads or anything else.

The megger will help to detect areas of deteriorating insulation where the windings may soon short. To check the condition of the armature windings the armature will probably have to be removed from the motor. Remember that the three phases have identical windings or. Set the voltage level of the insulation resistance tester to 500v.

This should allow you to isolate your problem. Set your multimeter to ohms. How to test your spindle motor for open or short in windings. This includes testing the motor for grounded windings.

If there is any reading on any of these then the motor is bad do not use it. With a multimeter set to low ohms usually 200 test between each winding terminal and the metal casing of the motor. U v w is a european winding designation. During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched.

Often it is required to test the winding of the 3 phase windings with the aid of a multimeter or ohmmeter to determine whether the motor is still good or burnt or shorted.