Electric Motor Winding Tester

With a multimeter set to low ohms usually 200 test between each winding terminal and the metal casing of the motor.

Electric motor winding tester. The megger will help to detect areas of deteriorating insulation where the windings may soon short. Set the voltage level of the insulation resistance tester to 500v. How to test your spindle motor for open or short in windings. This should allow you to isolate your problem.

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. Most repair shops will use a megger or a ground insulation tester. U v w is a european winding designation. The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works.

The most common failure mode of a 3 phase ac motor is burnt winding or shorted winding leading to the damage of the motor. We ll start with a quick review of why testing is important followed by a discussion of rotor bar hipot surge and motor winding resistance as well as a discussion of vibration analysis. Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor. Bearing problems may be the number one cause of electric motor failure but electrical faults are a close second.

Set your multimeter to ohms. If the winding s insulation wears away near the motor s case the bare wire winding shorts to ground. 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. This includes testing the motor for grounded windings.

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. Remember that the three phases have identical windings or. If there is any reading on any of these then the motor is bad do not use it. Technicians should perform a series of tests on an electric motor during routine preventive maintenance or before replacing it.

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. During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched. Test t1 to t2 t2 to t3 and t1 to t3. You may find that when it runs ungrounded that the casing becomes live at up to supply voltage.

While testing make sure the leads on each end are not touching other leads or anything else.