GB1029426A - Improvements in and relating to electric stepping devices - Google Patents

Abstract

1,029,426. Electric synchronizing. LICENTIA PATENT-VERWALTUNGS G.m.b.H. March 1, 1963 [March 1, 1962], No. 8364/63. Heading H2L. A stepping device comprises a polarized motor 13 in which incremental rotation is caused by pulses 16 from an electric source, an additional D.C. motor 14 being provided to produce an aiding torque, the motor 14 being controlled by pulses from the same source. A full-wave rectifying bridge 22 has its input connected through capacitor 23 and resistor 24 to the pulse source 16, output from the bridge rendering transistor 21 conductive and transistor 19 non-conductive so that motor 14 exerts maximum aiding torque. When there is no output from bridge 22, the motor 14 is short-circuited through transistor 19, and no aiding torque is applied to shaft 15. In another arrangement, the motor 14 is of the singlephase induction type, the supply to which is controlled by a saturable reactor having its control winding connected to the collector of the transistor 21, Fig. 4 (not shown). In a further embodiment, the aiding torque is provided by a coupling having an eddy current disc mounted on the rotor shaft of the motor 13. A constant speed servo motor rotates a frame of the coupling which carries windings energized in accordance with the pulse rate of source 16, Fig. 5 (not shown). The motor 13 has a four-pole rotor co-operating with four pole-pieces on the stator, the stator and rotor pole spans being similar. North and south poles are alternately arranged on both the stator and rotor. Opposite voltages are applied to the stator windings as a change-over switch is operated, each pulse causing rotation through 90 degrees, Fig. 1 (not shown).