Field computation of efficiency of induction machine working on unbalanced conditions using modified non-intrusive air-gap method

Various techniques have been suggested for efficiency estimation of Induction Machines (IMs) with different levels of intrusion and accuracy. Traditional methods depicted in IEEE Standard 112 can’t be employed for industrial environment where continuous industrial processes are in occurrence. This paper put forth an approach for non-intrusive air gap torque evaluation for efficiency estimation of IM by utilizing IM terminal quantities like input voltages and input currents. Base difference between Method-E and air-gap torque method is discussed. In vector control system, the speed estimation of IM is done based on Model-Reference Adaptive System (MRAS) by utilizing input electrical quantities and instantaneous reactive power. Algorithm used does not need intrusive no load testing. Experimental validation is carried out to verify the effectiveness of the proposed structure.