ABSTRACT

Pp , Pc are the pole-pairs number of power windings and control windings;

If the stator’s output power of the first machine is PN, the slip of the two machines are sp, sc when running in a speed. The mechanical power of the first machine can be obtained as follows:

PwpP p N( )s (1)

1 INTRODUCTION

In recently, variable frequency speed adjusting technology has been widely applied in many fields. The installed capacity of the traditional squirrel cage and wound rotor asynchronous motor has been greatly restricted because of respective disadvantages and limitations with the need of energy and cost saving[1,2].