Electric Motor Testing With Multimeter

If there is any reading on any of these then the motor is bad do not use it.

Electric motor testing with multimeter. Ac motor winding resistance test check the motor winding resistance or ohms reading with a multimeter. If the motor is completely unresponsive no ac humming or false starts take a reading at the motor terminals. Since there are three terminals. Klein tools multimeter test kit contains mm300 manual ranging klein tools multimeter test kit contains mm300 manual ranging digital multimeter ncvt 1 non contact voltage tester and the rt105 receptacle tester.

With a multimeter set to low ohms usually 200 test between each winding terminal and the metal casing of the motor. It can sometimes be very confusing to test fan motors for people who don t have much experience. If there is no voltage or reduced voltage work back upstream. This tester is capable of providing diagnostic information for all sorts of motors.

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. It measures the same or similar to the voltage you noted from the label on the electric motor if power is reaching the motor. As you probably know fan motors can be designed for several different purposes most common of these are single phase motors. Check that the correct voltage is applied to the motor.

If you have a reading and your motor isn t operating it s certain the motor is the problem and needs replacing. Each winding leg should have some small resistance. Power supply test for single phase motors the expected voltage is about 230v or 208v depending whether you are using the uk or america voltage system. Consult the motor schematic or a diagram of the motor s windings and use the meter to measure the resistance of the windings.

When an electric motor is broken one suspect is the armature with commutator of the motor. 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. On the plus side the only items needed to perform the test is an electrical schematic of the motor along with a multimeter. Check the multimeter measurement.

You may find that when it runs ungrounded that the casing becomes live at up to supply voltage. A wide range of dmms are available to measure voltage current and resistance depending on the motor power ratings. A dmm digital multimeter such as this keithley dmm7510 from tektronix is a must have instrument for motor testing. The ncvt 1 automatically detects standard voltage in cables cords circuit breakers lighting fixtures switches outlets and wires.

Preliminary often definitive tests generally take place using the ubiquitous multimeter.