Hindustan AC Motor

New international efficiency classes of motors (IE = International Efficiency)The new IS: 12615-2011 defines the following efficiency classes of low-voltage threephaseasynchronous motors in the power range from 0.75 kW to 375 kW. IE1 = Standard Efficiency (comparable to EFF2) (only for variable frequency driveapplication). IE2 = High Efficiency (comparable to EFF1) IE3 = Premium Efficiency IE4 = Super Premium EfficiencyThe higher the efficiency class the higher is the complexity of motor production and thehigher is the amount of material to be used (as for instance copper) & the motor pricewill increase accordingly. In relation to the motor life time the purchase price is only afew percentage points and due the saved energy cost the pay-back period is short.Although over a motors lifetime energy represents over 97% of its operating costs, thepurchase of new motors is driven by price and not the energy it will consume. It isbecoming clear that by investing a little more money on a high efficiency motor theinvestment can be paid back with energy savings.Motor manufacturers have advanced the technology over the years allowing theproduction of High efficiency-IE2 and Premium efficiency-IE3 motors. Soon to beadded to this list – and currently in development – are motors coming under theumbrella of Super Premium Efficiency or IE4 motors.The efficiency levels according to IS: 12615-2011 are measured with the new methodstipulated in IS/IEC 60034-2-1. In a direct comparison of both measuring methods atthe same motor, it is expected that the efficiency levels determined according to thenew method are up to a few percentage points below the efficiency levels using the oldmethod. To achieve compatibility with the old EFF1 and EFF2 classes, the limit valuesof IE2 and IE1 classes were lowered slightly. For example, a today’s 11 kW, 4-poleEFF1 motor with 91.0% efficiency is identical with a new IE2 motor with 89.8%efficiency. The