What Does NEMA Frame Size Tell You About Rigid Base Motors

July 16, 2024

Motor Minute^™ Technical Tip – What Does the NEMA®* Frame Size Tell You About Rigid Base Motors?

Hi, Chris from Regal Rexnord here with your Motor Minute technical tip. Helping you become an HVAC motor pro one minute at a time.

Today’s Motor Minute topic is NEMA frame sizes and rigid base motors.

The NEMA frame size directly correlates to the dimension between the center of the shaft in the motor and the mounting base. The reason this dimension is so important is to ensure that the replacement motor shaft will be in the same location as the original motor.

It is important to note that the NEMA frame dimensional standards correlate to a motor with a rigid base (also referred to as base mount or foot mount). This means that the mounting location of the motor in relationship to the center of the shaft is a fixed dimension.

For the replacement motor to match the location of the existing mounting holes and the center of the shaft of the motor being replaced, the frame size is crucial.

When selecting a replacement rigid base motor, the frame size is just as important as the electrical ratings but is often overlooked and widely misunderstood.

And that’s a wrap on this segment of Motor Minute technical tips. Remember that we provide motor training and product information in multiple formats including videos, literature, podcasts, articles, of course Motor Minute technical tips and classroom education both online and face to face. All of this industry leading training is available at no charge to HVAC professionals at regalmmu.com. Thank you for taking the time to build your motor knowledge.

_{*NEMA is the trademark of the National Electrical Manufacturers Association and is not owned or controlled by Regal Rexnord Corporation.}