A prediction of starting performance of solid poles synchronous motor.

Abstract

It is almost impossible to measure the starting performance of middle and large synchronous motors in a factory, bacause it needs a large capacity of equipments to test its performance. A new method is required to predict this performance by simple tests using a small capacity. This will make the motor's design and its accessories more rationalized. Authors propose a new method which is the combination of single phase AC applied test and usual routine test of synchronous machines. The key points of this method are summarized as follows: (1) A single phase voltage with commercial frequency is applied to armature terminals in a standstill condition. And this test must be performed twice in the same gap voltage, one for short-circuiting the field winding, the other for joining a resistance between the field terminals. Using these two test data including input power, the field and the damper winding impedances are separated from each other. (2) Solid poles resistance and reactance changes with a magnetic flux density and frequency. Therefore, authors assume the impeadance of solid poles to be a function of magnetic flux density and frequency from actual test values.The starting performance of a synchronous motor is predicted and agreed with actual data.