The present document gives technical guidelines for the application of energy-efficient motors in constant-speed and variable-speed applications. It does not cover aspects of a pure commercial nature.
Standards developed by IEC/TC 2 do not deal with methods of how to obtain a high efficiency but with tests to verify the guaranteed value. IEC 60034-2-1 is the most important standard for this purpose.
For approximately 15 years regional agreements were negotiated in many areas of the world regarding efficiency classes of three-phase, cage-induction motors with outputs up to about 200 kW maximum, as motors of this size are installed in high quantities and are for the most part produced in series production. The design of these motors is often driven by the market demand for low investment cost, hence energy efficiency was not a top priority.
In IEC 60034-30 IE efficiency classes for single-speed cage-induction motors have been defined and test procedures specified:
IE1 IE2 IE3 IE4
Standard-Efficiency High-Efficiency Premium-Efficiency Super-Premium-Efficiency
Determination of efficiency for motors powered by a frequency converter will be included in IEC standard 60034-2-3.
However, for motors rated 1 MW and above, which are usually custom-made, a high efficiency has always been one of the most important design goals. The full-load efficiency of these machines typically ranges between 95 and 98%. Efficiency is usually part of the purchase contract and is penalized if the guaranteed values are not met.
With permission from NEMA, some parts of this TS are based on NEMA MG 10, “Energy Management Guide For Selection and Use of Fixed Frequency Medium AC Squirrel-Cage Polyphase Induction Motors”.