Selection of replacement motors is usually straightforward if the ratings are equivalent. Sometimes, however, a different type of motor is necessary or desirable. For success in these cases, it is essential that the replacement motor provide the required performance — and do so reliably.

The Institute of Electrical and Electronics Engineers (IEEE) has published a new standard: IEEE Std. 3004.8-2016, “Recommended Practice for Motor Protection in Industrial and Commercial Power Systems.” If you’re an electrical professional who deals with a broad spectrum of motor protection schemes, including low- and medium-voltage AC and DC motors, then you need to become familiar with this standard.

An important step when selecting a centrifugal pump and an electric motor for an application or when troubleshooting operation issues is to determine how much power the pump should be using.

If you work with electric motors and pumps, you’ll eventually encounter a pump curve and one of its key parameters — best efficiency point (BEP). The BEP is the point on the curve where the pump operates most efficiently. Unique to each pump, the BEP is a product of both impeller design and several related pump curve parameters.

When an electric motor will be stored a long time before being placed in service, you must take certain steps to ensure it will be suitable for operation when it’s needed. One practical limitation to recognize is that much of what is done when preparing a motor for long-term storage must be undone when it is moved into operation. Storage procedures generally depend on the size of the motor and whether it will be out of service short term (several weeks) or long term (several months).