how does a synchronous ac motor work? please help!!!
A synchronous motor has a stator coil energized with an ac voltage of a given frequency. This creates a rotating mag field about the rotor. Unlike a typical induction motor, the sync motor rotor will also have a coil, energized with a dc field. The motor is accelerated to near sync speed by induction, when near sync speed the dc field lock onto the rotating stator field and the rotor, and therefore the shaft, rotates at a fixed rpm, which is dependent upon the applied frequency and the number of (always a multiple of two) distinct coils on the stator, e.g., 60 Hz motors will have rated rpm of 3600, 1800, 1200, 900, etc. The sync motor increases power by drawing more amps and varying its power factor-the induction draws more amps as well, but also slows below its sync speed.
They're also called stepper motors. Here ya go!
The magnetics synchronize to the 60 or 50Hz frequency of the line voltage. So the motor spins at 60 or 50 RPS or 3000RPM or 3600RPM respectively. And they are not called stepper motors. They are called squirrel cage induction motors or could be capacitive start induction motors.
