Electric Motor Testing With Multimeter

A dmm digital multimeter such as this keithley dmm7510 from tektronix is a must have instrument for motor testing.

Electric motor testing with multimeter.

When testing voltages to electric dryer heating elements and electric range or stove elements look for 240 volts ac. July 1 2015 by david herres 14 comments. When an electric motor fails to start runs intermittently runs hot or continually trips its overcurrent device there my be a variety of causes. The target voltage depends on the type of appliance you have and the components you re testing.

It can sometimes be very confusing to test fan motors for people who don t have much experience. It measures the same or similar to the voltage you noted from the label on the electric motor if power is reaching the motor. If there is any reading on any of these then the motor is bad do not use it. The other difficulty is that the multimeter is.

With the appliance turned off touch the multimeter s leads to the circuit. You may find that when it runs ungrounded that the casing becomes live at up to supply voltage. Examine the name plate thoroughly. A wide range of dmms are available to measure voltage current and resistance depending on the motor power ratings.

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. This guide will hopefully make testing fan motors for you easy regardless of your experience level or type of fan motor that you are testing. Check the multimeter measurement. A good motor should read less than 0 5 ohms.

As you probably know fan motors can be designed for several different purposes most common of these are single phase motors. Basic motor testing with multimeters and ammeters. With a multimeter set to low ohms usually 200 test between each winding terminal and the metal casing of the motor. 3 as with all testing and inspections the motor name plate provides valuable information that will help to ascertain the true health of the motor.

Earth continuity and resistance test with a multimeter measure the resistance between motor frame body and earth.