GB607195A - Improvements in or relating to gyroscopic instruments - Google Patents

Abstract

607,195. Gyroscopic compasses. SPERRY GYROSCOPE CO., Inc. Feb. 25, 1944, No. 3573. Convention date, Feb. 26, 1943. [Class 97 (iii)] [Also in Group XXXVIII] A directional gyroscope is caused to seek the meridian by electricallyapplied torques controlled by the tilt of a gyro vertical. As shown, the rotor casing 14 of the gyro vertical is supported in the outer casing 12 by a gimbal 13. A stator 15, producing a rotating field, is carried by a pendulous bail 16 and gimbal 17 and cooperates with an inductor 21 fixed to the casing 14 to produce an erecting torque for the gyro vertical as described in Specification 492,670. The erecting torque is made small so that the gyro vertical assumes a permanent tilt in the E-W plane due to the earth's rotation. The directional gyro has a coil 30 on the outer casing 25 and magnets 31 on the rotor casing 29. The induced current in a secondary coil 35 fixed to the inductor 21 differs in phase from the three-phase current supplied to the stator 15 by an amount depending on the direction of tilt of the gyro vertical and this current after suitable amplification and rectification excites the coil 30 of the directional gyro in one or other direction according to the difference in phase, thus providing the torques which precess the gyro 11 towards the meridian. The three-phase current is supplied to the stator 15 through a three-phase transformer 41 having one set of windings fixed to the casing 25 and thus turning with the supporting craft and the other set of windings orientated by the vertical axis of the directional gyro. The phase of the current supply to the stator 15 is thus automatically altered to render the induced current in the secondary coil 35 independent of turning of the supporting craft. The gyro vertical 14 assumes a further tilt due to the speed and course of the supporting craft. This may be compensated by the manually-operated phase adjuster 47 or automatically as described in Specification 154,618, [Class 97 (iii)]. To enable the instrument to be used for determining the speed and course of the craft, the tilt of the gyro vertical may be measured by electrical means of the inductive type. The horizontal axes of the gyro vertical mounting are provided with armatures co-operating with three-legged wound magnetic core members 51 carried on pendulous bails 54. The output signal is variable in magnitude and phase with the angular displacement of the parts and may be measured by a D'Arsonval galvanometer.