The efficiency classes of electric motors are defined to distinguish motors that do the same job with less energy. The steps between IE3, IE4 and IE5 show how much of the electricity a motor consumes over its life is actually turned into mechanical work.

The IEC 60034-30-1 Classification

This standard defines the efficiency classes, in order, as IE1 Standard, IE2 High, IE3 Premium, IE4 Super Premium and IE5 Ultra Premium. Each higher class cuts losses noticeably against the one below; an IE5 motor, for example, brings losses about 20 percent lower than its IE4 counterpart.

How High Efficiency Is Achieved

Higher efficiency comes from a better-grade silicon steel core, more and lower-resistance copper, a tighter air gap and an optimised fan design. These improvements reduce the motor's heat loss; a cooler-running motor works without straining the Class F insulation and extends bearing life.

Which Class Makes Sense When?

The longer the operating hours, the sooner the higher efficiency class pays for itself. While IE3 may be balanced for a machine running a few hours a day, on a continuously running drive train an IE4 or IE5 choice recovers the price difference through energy saving. The decision should be weighed together with the duty profile and the electricity tariff.

Choosing an Efficiency Class with DRG

DRG Motor offers IE3, IE4 and IE5 class motors from 0.55 to 355 kW, 400 V / 50 Hz, in various pole and frame options. Share your application's operating hours and we can calculate which efficiency class gives you the shortest payback period.