Principle and characteristics of a new type AC servo motor `VARIFIELD´

The authors previously proposed a novel brushless synchronous motor, the half-wave rectified brushless synchronous motor (1989). Kyowa Kiden Co., Ltd. started production of a new type AC servomotor series named `VARIFIELD´, which is based upon this machine theory. This motor has simple and robust brushless structure and is maintenance free. It provides torque control operation over a wide speed range, from zero to the rated speed. In this paper, the authors describe the principle and present overall test results, such as steady-state characteristics and step response