Anomalous phenomena in the performance of parametric motors

An experimental study of some anomalous phenomena (such as intermittent rotation or normal-reverse rotation) of a parametric induction motor was conducted. The cause, operation mechanism, and a method of avoiding the abnormal phenomena are explained. It is shown that when the magnetic-flux distribution inside the core specified as A ₂ becomes nonuniform by the change of rotational speed, the parametric oscillations become unstable. When the magnetic flux flowing in the reverse direction is large, the direction of rotating field is reversed; if this is not the case the motor operates intermittently. A way to avoid the phenomena is to make the magnetic-flux distribution inside the stator core uniform by changing the value of the contact angle between cores A₁ and A₂. It is concluded that these results may be useful in the design of stable parametric motors