GB1206547A - Improvements in electromagnetic indicating or readout devices - Google Patents

Abstract

1,206,547. Electric motors. VERNITRON CORP. 26 July, 1968 [14 Aug., 1967], No. 35707/68.' Heading H2A. An electromagnetic indicating device comprises a fixed annular array of selectively energizable salient poles, a P.M. rotor mounted centrally of the poles, for rotation . to substantial alignment with an energized pole, an indicia carrying, drum mounted, for rotation with the " rotor, and at least one magnetic structure mounted for rotation with the drum and rotor and being slightly offset with respect to the magnetic axis of the latter, so that the magnetic .structure does not affect the alignment of a rotor and a stator pole when the latter is energized and subsequently de-energized, but when the polarity of the stator pole is reversed the magnetic structure moves into alignment with the stator pole, thus effecting incipient rotation of the rotor which then continues through 180 degrees. The device shown comprises five laminated salient poles 24 each carrying a winding 25, the poles being secured to an end plate 11 (which may .be non- magnetic) in which is journalled a shaft 12 which carries the P.M. rotor 30 and an indiciacarrying drum 35 (which may be non-magnetic). The magnetic structure comprises a plurality of magnetically soft pins 41 mounted in pairs diametrically opposite one another on a non- magnetic ring 40 secured to .the drum 35 so that the pins extend to the vicinity of the poles 24. There may be an even number of stator poles.