The efficiency of low-voltage induction motors is classified under IEC 60034-30-1. The classes run from IE1 (standard efficiency) to IE4 (super premium efficiency), with IE5 defined for future use. A higher class means lower losses for the same output power.
| Class | Description |
|---|---|
| IE1 | Standard efficiency |
| IE2 | High efficiency |
| IE3 | Premium efficiency |
| IE4 | Super premium efficiency |
Specifying a motor
- Rated power and speed (number of poles)
- Supply voltage and frequency
- Frame size and mounting arrangement (foot, flange or both)
- Enclosure protection (IP rating) and cooling method
- Efficiency class required
- Duty type and any hazardous-area requirement
Motors with variable frequency drives
A drive lets a motor run at the speed the process needs, which can reduce energy use on pumps and fans. When a motor will run on a drive, say so: insulation, bearing protection and cooling at low speed may need to be considered.