Improvements in magnetic materials and commutation techniques have enabled dynamoelectric machines to be significantly reduced in size while developing as much or more power than their larger, bulky predecessors. In some instances, the size reductions have resulted in machine structures having less than desirable rigidity. For example, some high torque, low speed motors are constructed with many poles at a large radius and have limited stiffness in the radial direction. Some of these motors may have an air gap diameter of about eight inches and a lamination stack height of about one and one-half inches. In order to maintain uniform circularity of the lamination stack so as to maintain a uniform air gap between stator and rotor, it is necessary to support the stator and rotor in a rigid frame. However, it is desirable to minimize the mass of frame structure necessary to provide such support.
In switched reluctance (SR) motors or in single phase motors, rigidity is particularly important since such motors generate torque pulsations which produce noise unless the magnetic structure is mechanically isolated from the base structure by a torsionally soft mount. Accordingly, it is desirable to provide a mounting structure for such dynamoelectric machines of relatively low mass, suitable for low cost mass production and which provides isolation of radial and torsional vibrations from the base structure.