GB501026A - Improvements in or relating to electric motors - Google Patents

Abstract

501,026. Motors. HIRSCH, R. Aug. 19, 1937, No. 22808. [A Specification was laid open to inspection under Sect. 91 of the Acts, Feb. 21, 1938.] [Class 35] A motor with its stator windings intermittently energized through a circuit breaker for operation with continuous or alternating- current has a switch for short-circuiting the circuit breaker to permit operation as a synchronous motor. In the form shown in Fig. 4 a variable condenser 2 is connected in parallel with each stator winding 1 and the stator has unshaded poles 39 and poles with shading coils 41. The rotor 33 has a squirrel cage winding 44. For synchronous operation the circuit breaker 37 is short circuited by the switch 23. If the switch 23 is closed when the motor is first energized it will start as an induction motor. Instead of cylindrical the rotor may be rectangular with curved ends and the stator may have two poles only. The circuit breaker may be operated by a cam 34, by a separate electromagnet, or by a reciprocating armature co-operating with the stator. The Specification as open to inspection under Sect. 91 comprises also intermittently energized motors without switches for permitting synchronous operation and motors with valves acting as interrupters. It also comprises unwound rotor motors with the windings 1, 1<1> energized alternately, Fig. 12 (Cancelled), This subject-matter does not appear in the Specification as accepted.