Electric Motor Replacement: What You Need to Know

by Glenn Caunt, Account Executive

When replacing an electric motor, there are many things to consider when purchasing your replacement motor.  There are many types of motors, and different types of electric motors. 

The AC motor consists of 2 basic parts.  The first common part is the stator.  The stator remains stationary and is usually connected to the frame of the motor.  The outside stator has coils that are supplied with alternating current to produce a rotating magnetic field in which the rotor spins. The other important part of the motor is the rotor.  The inside rotor is the part that rotates when the motor is in operation. The rotor experiences a torque due to the electromagnetic motor effect. 

Another part usually found in an AC motor is the ferrite core that confines the magnetic field.  The brushed AC motor can only run at a single speed. You cannot use a DC motor in place of an AC motor.

When replacing a motor, you should try to match up all the specifications to the motor that was working.  The tag will usually have all the information to match up correctly.  The important specifications you need to verify you matching up correctly are the horsepower, voltage, phase, RPM, and frame size.  For the electricity you need to know if your power is 115V, 230V, 460V etc.  Also, verify if the power is single phase, 2 - phase or 3 - phase.  Usually the phase is single phase or 3 - phase.  The horsepower and RPM are also important, to insure the motor spins at the same speed.  The frame size is also very critical, because it determines the way the motor mounts with a specific bolt pattern.  The frame number has been standardized by NEMA, so all manufactures of a certain frame will have the same bolt mounting pattern, shaft diameter, and shaft length.  Only special frames can have different bolt patterns or shaft sizes. 

All these important specifications are on the motors tag.  That is why it’s important to take a picture of the tag, so you can verify you’re getting the correct motor, the first time.

Call us today for your motor replacement at 800.464.0896.

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