Electric power source system for gyroscopic instrument

Claim 1

An electrical power source system for a gyroscopic instrument driven by polyphase A.C. motor comprising: a gyro rotor mounted in said gyroscopic instrument; a polyphase A.C. motor connected to drive said gyro rotor at high speed and having a plurality of windings; a single-phase electrical power source; a converter circuit means connected between said single-phase electrical power source and said polyphase motor for converting power from said single-phase source to polyphase power, a first capacitor in said converter circuit having a capacitance such that said capacitor resonates with the inductances of the windings of said polyphase A.C. motor in the region of the frequency of said single-phase power source, and whereby said single-phase electrical power source is interrupted when said polyphase A.C. motor operates as an induction generator being driven by said gyro rotor to supply electrical power; an electrical utilization circuit associated with said gyroscopic instrument electrically connected to said polyphase A.C. motor and energized thereby when said single-phase power source is interrupted, a second capacitor is inserted between two of said windings of said polyphase motor which are not connected to said first capacitor, a relay connected to said single-phase source for controlling a pair of movable contacts with one disconnecting said single-phase electrical power source and said utilization electrical circuit of said gyroscopic instrument and another movable contact connects said second capacitor in circuit, whereby when said single-phase electrical power source is interrupted, the first movable contact is opened and the second movable contact is closed to disconnect said single-phase electrical power source from said induction generator.