Three-phase electric motors are a common type of motor found in many industrial and commercial applications. They are more efficient than single-phase motors and can provide more torque, making them ideal for heavy-duty applications.  Three-phase motors have also become commonplace in electric forklifts and electric pallet jacks.Techtop General Purpose AC Motor

However, like all electrical equipment, three-phase electric motors can fail. To prevent this, it is important to test them regularly. By testing your three-phase electric motors, you can identify any potential problems early on and take steps to prevent them from causing a major failure.

There are a number of different tests that can be performed on three-phase electric motors. The most common tests that can be performed in the field with a multimeter with megohm test functionality include:

  • Continuity test: This test checks for continuity between the motor windings and the motor frame. A continuity test should always be performed before any other tests, as it can help to identify more serious problems.
  • Resistance test: This test measures the resistance between the motor windings. The resistance of each winding should be equal. If the resistance is not equal, it indicates that there is a problem with the winding. For three phase motors, the test should be conducted between 1-2, 2-3, and 3-1 circuit.
  • Insulation test: This test measures the insulation resistance between the motor windings and the motor frame. The insulation resistance should be high, typically in the megohm range. Any result lower than 1 meghoms at 500 test voltage is probably defective and requires further evaluation. A low insulation resistance indicates that the insulation is damaged, which can lead to a short circuit.
  • Bearing test: This test checks the condition of the motor bearings. The bearings should spin smoothly and without any noise. If the bearings are noisy or difficult to turn, they should be replaced.
Meter test three phase motor

Technician performaning an Insulation test on a three phase motor

By performing these tests regularly, you can help to ensure that your three-phase electric motors are in good working condition and that they will continue to operate safely and efficiently for many years to come.

Here are some additional tips for testing three-phase electric motors:

  • Always disconnect the motor from power before performing any tests.
  • Use the correct tools for the job. A multimeter is a must-have for testing three-phase electric motors.
  • Follow the manufacturer’s instructions. The manufacturer’s instructions will provide specific instructions and parameters for testing your particular motor.
  • Be careful. Three-phase electric motors can be dangerous. Always take the necessary safety precautions when working with them.

By following these tips, you can safely and effectively test your three-phase electric motors