IE3 and IE5 efficiency classes for gearmotors: what changes
In a gearmotor, consumption depends on two factors: the electric motor efficiency (IE classes) and the reducer efficiency. Understanding them helps you stay compliant and cut the bill.
The motor IE classes
The IE (International Efficiency) classes rate the induction motor: IE2, IE3, IE4, IE5, in ascending order. The EU EcoDesign regulation has long required IE3 across a wide power range, with IE4 mandated for some bands. IE5 is the highest reference available today (often permanent-magnet technology).
How much you save
An IE5 motor can cut losses by 20–40% versus an IE2 of equal power. On a drive running many hours a day, a few efficiency points are worth hundreds of euros a year.
Reducer efficiency matters as much as the motor
Total efficiency is the product of motor and reducer efficiency. An IE5 coupled to a low-efficiency worm wastes part of the gain: for maximum saving, pair a high-class motor with a coaxial or bevel-helical reducer (95–98% per stage).
Permanent-magnet motors and inverters
Gearmotors with a permanent-magnet synchronous motor (PMSM), driven by an inverter, keep high efficiency even at part load, where traditional induction motors lose efficiency. It is the ideal choice for variable-speed cycles.
Efficiency classes are shown on the product pages. To size correctly, see our guide to output torque and speed.
Häufige Fragen
What is the difference between IE3 and IE5?
They are ascending motor-efficiency classes: IE5 is the highest and cuts losses by 20–40% versus IE2/IE3, often via permanent-magnet technology. IE3 is the minimum required for many power ratings.
Does reducer efficiency affect consumption?
Yes: total efficiency is motor × reducer. An IE5 motor performs best paired with a high-efficiency coaxial or bevel-helical reducer, not a high-ratio worm.