GB221991A - Improvements in and relating to electric motors operating on pulsatory or single-phase alternating current - Google Patents

Abstract

221,991. Fontana, C., and Ferrari, V. Nov. 3, 1923. No Patent granted (Sealing fee not paid). Rotary machines; oscillating machines; motors with unwound iron armatures. - A motor operating on pulsatory or singlephase alternating current comprises a laminated electromagnet a having internally projecting poles with inclined faces and mounted on a rotatable bushings. A laminated armature b, which may or may not be wound, has outwardly projecting poles with their faces parallel to the electromagnet polefaces and is mounted on a rotatable bushing t. A sleeve d surrounding the outer core and an inner sleeve e surrounding the shaft are formed with two sets of oppositely inclined grooves in the planes A-B and E-F, and in these grooves are located spring-pressed balls engaging with rings i, i<1> on the bushing s and shaft respectively. A key u is provided between the bushing t and sleeve e to permit of relative axial movement. The casing f is formed with a helicoidal slot g through which passes a handle h screwed into the sleeve d. The sleeves are connected together by resilient rods m engaging at their outer ends in a circular groove and fixed at their inner ends. The rods pass through straight axial slots r in the bushing t and through slots q, having the shape shown in Fig. 3, in the bushing s. When the coils of the electromagnet a are excited, the armature b is attracted in a clockwise direction. An impulse is thus given to the motor shaft by the action of the balls in the sleeve e on the ring i<1>. The core a is prevented from moving anti-clockwise by reason of the spring-pressed balls in the sleeve d located in the plane A-B, but is moved forward by the blow delivered by the armature. When the current in the coils falls to zero, the rods m separate the two cores, and at the next current impulse the same cycle of operations is repeated. In order to decrease the speed of the shaft, the handle h is moved along the slot g, and this results in an axial movement of the sleeves d, e. At the same time, the outer ends of the resilient rods m pass along the inclined portion 4 - - 2 of the slot q, which causes relative angular movement of the cores and consequent diminution of the air gap. Continued movement of the handle causes the balls lying in the plane E-F to engage with the rings i, i<1>, and the motor is reversed. Further movement brings the rods m into the portion 3-1 of the slot q and the speed of the motor is increased owing to the larger air gap formed by the separation of the cores. The core a may be fixed in the casing, in which case the oscillatory movement of the armature is converted into rotary movement of the shaft. Current is led in by slip-rings l.