Nonintrusive method of residual losses estimation in squirrel cage induction motors

Electric motors have broad applications in the industrial sector such as water and waste-water pumps, compressors, funs and others. They use about 30%-80% of total industrial energy around the world (e.g. it is expected that 62,500 GWh electricity, or 56% of total output of electricity in Poland, is used to drive equipment). Therefore the cost of energy to operate motors has become a real concern for industries. Energy usage evaluation and condition monitoring for electric machines are important in industry for overall energy savings. On average, these motors operate at no more than 60% of their rated load because of oversized installations or underloaded conditions, and thus at reduced efficiency. A variety of methods are applied to reduce electricity consumption.