IE classes grade how much of the electricity drawn by the motor is converted into shaft power. Our catalogue covers three levels: IE3 Premium, IE4 Super Premium and IE5 Ultra Premium. At the same power and pole number, the higher class has lower permitted losses.

7.5 kW, 4-pole, 50 HzNominal efficiency limitLoss share
IE390.4%9.6%
IE492.6%7.4%
IE594.0%6.0%

These are the limit values of the standard; each model's own rated efficiency is given separately in the catalogue model tables.

What decides which class makes sense:

  • Annual operating hours: on a machine running a few hours a day, the monetary value of the class difference stays small; on a pump or fan running three shifts it grows.
  • Load factor: if the motor is not sized close to the real operating point, part of the higher class's advantage is lost.
  • Electricity unit price and the expected service life of the motor.

Ranges: IE3 premium efficiency motors, IE4 high efficiency motors and IE5 electric motors.