Power circuit for switching the number of poles on the rotor of synchronous machines by using rotative diodes

A circuit for changing poles of the rotor of a synchronous machine, comprising:

• first and second slip rings;
• contact brushes in operative connection with said first and second slip rings;
• means for reversibly connecting said contact brushes to an electrical current source;
• first pole coils operatively connected to one of said slip rings;
• a circuit portion operatively connected with the other of said slip rings and including second pole coils, and first and second diodes between said second pole coils and said other slip rings;
• a third diode between said first pole coils and said circuit portion, said first, second and third diodes all being arranged so as to permit the flow of current through said first and second pole coils in a direction towards said second slip ring;
• and
• a circuit branch having one terminal which is connected between said first pole coils and said third diode and another terminal which is connected between said second pole coils and said first diode, said circuit branch including a fourth diode arranged so as to permit the flow of current through said first pole coils in a direction towards said first slip ring but to inhibit the flow of current through said second pole coils in a direction towards said first slip ring.