Buying tips—electric motors

What should you consider when buying an electric motor?

Use CanMOST.
To choose the right motor for your facility, you must know the motor type (its size, speed and enclosure) and motor load (constant or variable). CanMOST, the Canadian Motor Selection Tool, can help you identify the best motor for your precise needs.

Pick the right size for the job.
Motors are most efficient when they operate at between 75 and 100 percent of capacity. It is therefore critical that you select the right sized motor for the job and do not deliberately choose an oversized motor to accommodate for future expansion.

Check your speed.
Some energy-efficient motors run faster than standard units. This can negate potential energy savings. Select a new motor that has a full-load operating speed less than or equal to that of the old motor.

Incorporate a variable frequency drive.
Variable frequency drives regulate motor speed to match load demand. The benefit: energy savings of as much as 50 percent in some applications.

Keep your eye on the power factor.
A motor’s power factor is the ratio of real power (the power being used by the motor) to apparent power (the power you pay for). Motors that run at the peak of their rated loads have high power factors and are particularly efficient. Conversely, lightly loaded motors are highly inefficient. When you choose a new energy-efficient motor, make sure the new motor’s power factor is higher than that of the old unit.