A Trial Three-Phase Two-Pole Six-Slot Small Concentrated-Winding Squirrel-Cage Induction Motor and Its Basic Characteristics

Abstract

With the increase in the use of three-phase squirrel-cage induction motors (IMs), there is a need for not only increasing the efficiency but also reducing the cost of the IMs. The stator winding structure of typical IMs is the distributed winding, and the length of coil end on the IMs relatively increases as the output and number of poles decrease. If a concentrated winding (CW) structure is used, the cost will reduce owing to shorter coil ends. However, the characteristics of CW-IM worsen because of the influence of magnetomotive force harmonics. In this study, we investigated the CW-IM, and determined that CW is effective in two-pole small IMs, and thus developed a trial CW-IM. This paper discusses about the effects of the stator core shapes on the characteristics of the CW-IM and describe the characteristics of trial CW-IM. The results show that the stator teeth and yoke width must be appropriately sized, the amount of copper and axial length could be reduced with CW, and an abnormal torque is occurred. With regard to abnormal torque, the use of a rotor with appropriate skewed slots is propose to be effective.