Electric Motor Testing With Multimeter

You may find that when it runs ungrounded that the casing becomes live at up to supply voltage.

Electric motor testing with multimeter.

A dmm digital multimeter such as this keithley dmm7510 from tektronix is a must have instrument for motor testing. 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. Since there are three terminals. Check that the correct voltage is applied to the motor.

It measures the same or similar to the voltage you noted from the label on the electric motor if power is reaching the motor. In this video we show different tests 180 degrees test bar to. If you have a reading and your motor isn t operating it s certain the motor is the problem and needs replacing. A wide range of dmms are available to measure voltage current and resistance depending on the motor power ratings.

The ncvt 1 automatically detects standard voltage in cables cords circuit breakers lighting fixtures switches outlets and wires. Consult the motor schematic or a diagram of the motor s windings and use the meter to measure the resistance of the windings. 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. Each winding leg should have some small resistance.

As you probably know fan motors can be designed for several different purposes most common of these are single phase motors. You should perform this test whenever you see cracks or burn marks or you ve noticed a burning odor coming from the motor. Preliminary often definitive tests generally take place using the ubiquitous multimeter. If there is any reading on any of these then the motor is bad do not use it.

When an electric motor is broken one suspect is the armature with commutator of the motor. Ac motor winding resistance test check the motor winding resistance or ohms reading with a multimeter. With a multimeter set to low ohms usually 200 test between each winding terminal and the metal casing of the motor. Check the multimeter measurement.

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. This tester is capable of providing diagnostic information for all sorts of motors. If the motor is completely unresponsive no ac humming or false starts take a reading at the motor terminals. On the plus side the only items needed to perform the test is an electrical schematic of the motor along with a multimeter.

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.