GB597282A - Improvements in or relating to control means for gyroscopes - Google Patents

Abstract

597,282. Control of A.C. motors; thermal switches. BARNES, J. W. Aug. 13, 1945, No. 20721. [Classes 38(iii) and 38(v)] [Also in Group XX] The supply circuit connections of an electric motor 11 controlling the erection or precession of a gyroscope, are temporarily altered by a manual control 28, actuation of which simultaneously adjusts a switch to modify the motor supply connections and sets a delayed-action device which operates subsequently to return the switch to its initial condition and so restore normal supply to the motor. As shown, the motor is normally energised over a resistance 18 and through a two-way mercury switch 12 carried by a gymbol ring of the gyroscope, and the action of control 28 is to short-circuit the resistance and so accelerate the motor. The switch actuated by control 28 may comprise a fixed contact 24, a movable contact 19 and a contact 25 carried by a bimetallic strip 26 having a heater 20 and associated with further bimetallic strip 30 for ambient temperature correction. Contact 19 is carried by a bowed spring 27 and normally engages contact 24, thereby short-circuiting heater 20. When acceleration of the motor is required the spring is moved over its dead centre by control 28, so that contacts 19, 25 engage and short circuit resistance 18. Heater 26 becomes energised from lines 15, 17 through power factor correction condenser 21 and the consequent flexing of strip 26 eventually moves the spring 27 over dead-centre and restores initial connections.