Motor service factor

Finally, some nameplates may even include data like bearing identification numbers, certification code, manufacturer serial number, and symbols and logos. In order to fully understand the details presented on motor . Motor Service Factor (SF) is the percentage of overloading the motor can handle for short periods when operating normally within the correct voltage. Temperature Rise (º C) vs Percent Loading.

EASA Technical Support Specialist.

It also allows for cooler winding .

Understanding how the service factor affects an electric motor can be confusing, but it is not as complicated as it may seem.

This issue of the Franklin AID explains the term service factor and its relationship to AC submersible motors. It is common on some higher horsepower, or application specific motors to be 1. SF based on special design, enclosure size etc. The first is motor temperature. There are two aspects to Service Factor.

One of the common problems with electric motors is that their performance decreases with loads lower than . Despite overrating being the most common problem, . In response, a competitor would increase the power of its motor , and so forth.

It eventually became very difficult to compare motors from different manufacturers, and in time, standards were established and became known as service factor. Today, the National Electrical Manufacturers Association (NEMA) . The Nomenclature Of Service Factor On An Electric Motor Nameplate Is Designated By S. Common values of service factor are 1. Corrected references in subclause b . Although many motors have service factors of. Never operate over- loaded when voltage is . How to Calculate Motor Service Factors. Horsepower ratings of motors have been standardized by NEMA.

Figure which is an excerpt from the NEMA Standards, lists the horsepower ratings available.

The most commonly used motors are squirrel cage induction motors. For this reason, NEMA standards for service factor were set higher especially on lower horsepower motors for pump . Overloaded motors can overheat and lose efficiency. Most electrical codes allow the overload protection to be set up to 1 or 1 for 1. Some motors , especially large older ones , have. The service factor is typically in the 1. However, when sizing submersible wastewater pump motors .