syncronous stepper motor

[mottt]

hi everybody on this new year, i hope all is ok, I got a friend that ask me a question about a little motor he gots on his office, it´s a syncronous stepper motor, this is writed on the nameplate of the motor, and it´s feed on 240 V ac 50/60 hz, and it gots three cables for conection, they are the same circuit.. does somebody knows how it works, the manufacturer is woodward, and the aplication is a speed government for a diesel motor... i appreciate all the info....

 

[sreid]

Its probably what was originally called a SLO-SYN motor. Basically the construction is the same as a stepper motor except the winding are for higher voltages. One phase winding is driven directly off the line and the other phase is driven off the line thru a capacitor. This creates a phase shifted signal so that the two phase currents create a rotating manetic field. The motor shaft turns continously due to the sine wave currents. The shaft turns slowly based on the number of poles in the motor, usually a large number