Synchronous machine with switching element in the excitation circuit

A separately-excited synchronous machine comprising:

• a rotor-side circuit arrangement;
• an excitation circuit in said rotor-side circuit arrangement;
• said excitation circuit having an excitation winding;
• a power supply for said excitation winding;
• a first rotor-side secondary winding at least partially forming said power supply;
• a switch configured to connect said power supply to said excitation winding;
• said first rotor-side secondary winding being electrically coupled to a first stator-side primary winding;
• and,
• a second rotor-side secondary winding which is electrically coupled to said first stator-side primary winding, said second rotor-side secondary winding being connected to a control of said switch.

A separately-excited synchronous machine comprising:

• a rotor-side circuit arrangement;
• an excitation circuit in said rotor-side circuit arrangement;
• said excitation circuit having an excitation winding;
• a power supply for said excitation winding;
• a rotor-side secondary winding at least partially forming said power supply;
• said rotor-side secondary winding being electrically coupled to a first stator-side primary winding;
• a switch configured to connect said power supply to said excitation winding;
• a resistive load connected in parallel to said switch;
• a control configured to controllably selectively open and close said switch;
• a control circuit containing said control, said control circuit including a rotor-side voltage source configured to power said control;
• an opto-coupler configured to controllably connect said rotor-side voltage source to said control so as to operate said switch, said opto coupler having a photo-sensitive element in said control circuit, and said opto-coupler having a controllable light source configured to provide a control signal to said photo-sensitive element.