ABSTRACT
Historically, the reverse rotation test at low voltage and rated current has been considered as an acceptable way of segregating stray load losses. Traditionally, the stall rotor test is carried out with a three-phase supply and mechanical blockage to stall the rotor. The calorimetric method is based on the principle that the temperature rise in a wall-insulated chamber is proportional to the losses dissipated inside. Due to its impact on energy costs, efficiency is the single most important parameter index in electric machines. As induction motors are fabricated and used worldwide, national and international standards for efficiency measurements have been introduced. The efficiency is estimated by determining all loss components of the induction machine (IM). In accelerating–decelerating Method the IM is supplied from an off-the-shelf pulse width modulation converter – even one with unidirectional power flow will do. For the large-power IMs, direct loading to evaluate efficiency and temperature rise under load involves high costs.
