GB346417A - Improvements in and relating to the regulation of the speed of electric motors - Google Patents

Abstract

346,417. Motors. ZETSCHE, J., 11, Grabenstrasse, Hamburg, Germany, and ROSS, J. SINCLAIR-, 1, Morpeth Terrace, London. Dec. 12, 1929, No. 38132. [Class 35.] Rotary machines ; motors, controlling.-In motors of the type described in Specifications 327,249 and 328,722, [both in Class 35, Dynamo-electric generators &c.], the speed and torque are varied inversely by varying the air gap between the closed iron stator and rotor pole-rings. As shown, the stator coils 2 are wound on bobbins, the cores 4 of which are secured by screws between the baseplate 1 and a, closed iron ring 6. The rotor comprises an iron disc 7 keyed upon the shaft 8. The cores 11 of the bobbins are secured by screws between the disc 7 and a closed iron ring 13. The rotor shaft is supported by an antifriction footstep bearing comprising a steel ball 14 which is held between the shaft and a screw 16. The screw 15 works in the tapped portion of the bearing-bush 16 or the opening 17 of the boss 18 carrying the bush 16 may be tapped. The screw 15 is provided with a knurled head 20 and a pointer 21 so that as the screw is rotated to vary the air gap 19, the pointer 21, in conjunction with a calibrated scale attached to or marked upon the boss 18, gives an indication of the speed. A spring 23 is arranged between the head 20 of the screw and the bush 16. The commutator 24 is arranged at the end of the rotor remote from the stator so that by unscrewing the screws 30, the casing 28 carrying the brush gear 26 can be removed without disturbing the footstep bearing.