The hysteresis motor-advances whick permit economical fractional horsepower ratings

The theory of the development of torque in a hysteresis motor is analyzed from both the hysteresis lag angle and total loop energy points of view. A new development, comprising the use of a closed slot stator in co-operation with a hysteresis rotor, which permits building hysteresis motors of high power output at high efficiency is explained qualitatively and supplemented by considerable quantitative experimental data. A new method of stator construction, permitting the use of closed slot stator laminations assembled on a mandrel with non-magnetic bearing supporting spiders, wound externally in either a d-c type of armature winding machine or with form-wound coils, impregnated with a thermosetting resin and baked to form a unitary structure, is described. The electrical design of the machine is covered and quantitative data on both design details and operating characteristics are given on several models.