Experimental Study of Inter-Bar Current Effects in Three-Phase Squirrel-Cage Induction Motor

Recently, induction motors (IMs) have been used as power sources for industrial machines. In general, middle and small size IMs have skewed rotor-bar slots using die cast to reduce abnormal starting torque and electromagnetic vibration and noise. Then, the current in the direction of the rotation (inter-bar current) adversely affects the starting characteristics and decreases the motor efficiency of the IM. Hence, we have studied the effects of the inter-bar current on the characteristics of IM, which has a rotor with skewed slot, a rotor with a skewed slot and short-circuited by two aluminum rings, or a post-heated rotor. In this study, we examine the effects of the inter-bar current on the IM characteristics based on experimental results obtained from several test motors.