GB751018A - Improvements relating to gyroscopes - Google Patents

Abstract

751,018. Electric indicating systems. GENERAL ELECTRIC CO. Jan. 13, 1954 [Jan. 13. 1953]. No. 1025/54. Class 40(1) [Also in Group XX] In. a gyroscope, magnetic-leakage-flux from the stator of the electric rotor-drivemotor induces in one pair of pick-off coils, an e.m.f. of magnitude and phase sense corresponding to the magnitude and sense of the deviation of the spin-axis from a normal direction. As shown, applied to a directional gyro, the main gimbal 2 mounted for rotation about the major (vertical) axis 4-4 in the fixed outer frame 1, carries pick-off coils 16, 17 mounted in planes parallel to the main gimbal frame and Parallel lel to the main gimbal frame and parallel to the major axis. As described in Specification 740,796 [Group XX], the gyro rotor preferably comprises symmetrical rotor halves 7, 8 rotatable on a shaft 9 about the spin axis 10-10, the rotor 'bearings being carrier by a bar-shaped member 11 positioned between the rotor halves and pivoted by trunnions 12 in the main-gimbal frame about the minor axis 6-6. The spin axis 10-10 is normally perpendicular to the major axis 4-4 so that leakage flux from the rotor drive induction motor stator 14-15, which is also perpendicular to the spin axis, has zero coupling with the pick-off coils. As the spin axis varies from the perpendicular relative to the major axis, the leakage flux will induce an output in the series connected coils 16, 17 of corresponding magnitude and phase sense. This output after amplification in a phase-sense sensitive amplifier 20 may actuate a torque motor 23, 24 operating on the major axis 4-4 to precess the gyro about the minor axis 6-6 and so restore the spin axis to its normal horizontal position. Phase adjustments of the pick-off signals relative to a reference signal required in the phasesensitive amplifier are effected by angularly adjusting the stator of the gyro rotor drive motor about the spin axis. The output coils 16, 17 may be tilted slightly out of parallel to adjust the pick-off output to zero in the normal position. Modifications. The invention may be applied to a gyro-vertical or rate-gyro. In the case of a gyro-vertical an additional winding may be mounted on the outer frame, the outputs derived from the two windings giving pitch and bank displacements of the supporting craft referred to the gyro-vertical spin axis, and operating attitude indicators. The output winding when fitted on the main gimbal, may also be used to carry D.C. signals for precessing the gyro about its major axis particularly in the case of a slaved directional gyro when being corrected azimuthally by a magnetic or fluxgate compass. The output winding, in this case, functions as the torque motor winding and co-operates with permanent magnets suitably disposed on the rotor structure to produce, by interaction, torques about the minor gyro axis, so as to precess the gyro about the major axis.