MOTOR MOUNTING CODES

 

MOTOR MOUNTING CODES

There are two different standards—NEMA and IEC—  which you will see when looking at electric motor mounting positions.  Although they are generally comparable, there are slight differences between the two.

Motor Mounting Arrangements (IEC standard 60034-7)

Proper motor installation and mounting position is essential in obtaining top-quality operation, efficient performance, and maximum reliability.  Sometimes, however, there is confusion about the many different ways a motor can be installed.  

There are two different standards—NEMA and IEC—  which you will see when looking at electric motor mounting positions.  Although they are generally comparable, there are slight differences between the two.

The standard IEC mounting position places the junction box on the top of the motor, known as the IM B3 mounting position in IEC frame (or F3 in NEMA frames).  On the other hand, the NEMA standard mounting position is referred to as F1, with the junction/conduit box located on the left side of the motor facing the output shaft.    

The design of  most motors is such that they can usually be operated in many mounting positions, unless indicated otherwise.  Some mounting positions, however, require additional construction modifications to achieve optimal performance.  For example, shaft-up or shaft-down outdoor applications may require drilling of additional drain holes, drip covers and stronger bearings to support heavy loads.  Don't just assume you can bolt any motor in any orientation!

Below is a visual reference of typical electric motor mounting positions.  Whether you're an installer, engineer, or maintainer, this is a must -have reference.