The gains might be small and the cost differential large if you change from a premium to a super-premium, or high-efficiency, motor. The extra expense can be worth it, though, given the duty cycle. However, other motor capabilities, such as being able to run efficiently enough at an appropriate and variable speed, might offer an even better payoff.
An illustration of these various ways to boost efficiency comes from Portescap. The company makes motors for smaller applications, with a line of stepper, dc and brushless products. The stepper motors have efficiency as high as 60%, while the brushless motors come in at +90%, roughly equivalent to the super-premium class of ac induction motors.
In the last half of 2013, the firm launched its Ultra EC series of brushless, slotless dc motors. These have several innovations, some of which are particularly important when it comes to efficiency, according to Dave Beckstoffer, Portescap’s project manager.