Electric motor and electric motor stator and method for making same

Abstract

A technique for forming stator coils for an electric motor is disclosed. The technique includes forming D-shaped or generally trapezoidal coils having a closed loop defining a long side and a short side joined by end portions. The coils are installed in a stator core having a plurality of slots formed around its inner periphery. The long sides of the coils are disposed in a predetermined position within these slots, such as in a lower position, while the short sides are disposed in opposite positions, such as in upper positions. The long sides extend beyond the short sides at end regions of the stator core. The end portions of each coil wrap around the ends of the stator core and incline from the long side of the respective coil to the short side thereof. Crossing points are established between the long side of each coil and end portions of adjacent coils. The crossing points are located in predetermined positions and the coils may be taped to insulate the long sides from the end portions at the locations of the crossing points. The physical spacing of the end portions owing to the trapezoidal shape of the coils reduces potential difference gradients between the coils, reducing the risk of corona breakdown in inverter drive applications and the like.