GB1199497A - Miniature DC Motor or Motor-Generator. - Google Patents

Abstract

1,199,497. D.C. motors and motor generators. TOKYO KAGAKU K.K. 19 Sept., 1967 [27 Dec., 1966], No. 42629/67. Heading H2A. A miniature D.C. motor or motor generator comprises rotatably mounted in bearings 8, 8<1> in two end plates of a casing 1 an assembly of a plurality of rotors 4, 4<1> each comprising a plurality of polepieces 6 on each of which is a winding 7 each rotor being mounted on a respective one of a plurality of coaxial shafts 5, 5<1> relatively non-rotatably coupled together and mounting a respective one of a plurality of commutators 9, 9<1> for each of which there is corresponding brushgear 11, 12, 11<1>, 12<1>, the casing also housing a respective stator for each rotor. As shown, the stators are pairs of magnets 3a, 3b; 3a<1>, 3b<1>, the casing is magnetic and forms one end plate, and the coupling comprises a complementary polygonal e.g. square projections and recess on the shaft ends; but alternatively the casing may be non- magnetic and house a magnetic yoke, and the coupling may be a hole with key and keyway. There may be more than two rotors and associated brushgear, and the end plate (2), Fig. 4, may be of plastics sufficiently resilient to be removable. The speed of a load driven by the motor when a supply is applied to rotor 4 can be determined by measuring the D.C. voltage generated in rotor 4<1>, and automatic speed control may be provided as described in Specification 1,198,646, by supplying this voltage to an amplifier. Alternatively, the windings 7, 7<1> may have differing thickness and/or number of turns for alternative motoring operation from different voltages