Analysis of efficiency characteristics of squirrel-cage induction motor for pump applications

Criteria of improving energy efficiency of water system pumping plants are formulated. Impact of pumps on a control system is defined. Efficiency characteristics of a squirrel-cage induction motor at varying rotational speeds and load torques are presented. The modified Air Gap Torque (AGT) method is introduced to determine efficiency of a squirrel-cage induction motor. Results of testing which continues the authors' work on application of AGT method to estimating induction motor's efficiency are discussed. The definition of estimated losses is presented. The proposed method is verified in a number of selected low-power motors.