Patent ID: 7528559

Claim:
A synchronous motor system comprising: at least one synchronous motor that includes a field winding system; a normal field excitation supply unit and a standby field excitation supply unit; and a control unit that normally connects said normal field excitation supply unit in circuit with said field winding system and that in response to a failure of said normal field excitation supply unit automatically changes over said field winding system from said normal field excitation supply unit to said standby field excitation supply unit, wherein said synchronous motor is one of a plurality of synchronous motors that each have a field winding system, wherein said normal field excitation supply unit is one of a plurality of normal field excitation supply units, each of which is associated with a different one of said synchronous motors, wherein said control unit responds to a failure of any one of said normal field excitation supply units to change the field winding system of the associated synchronous motor over to the standby field excitation supply unit.