GB1092361A - Force motor - Google Patents

Abstract

1,092,361. Electromagnets. ULTRA ELECTRONICS Ltd. May 8, 1964 [Feb. 8, 1963], No. 792/63. Heading H1P. A force motor comprises an armature consisting of a central magnet 11 flanked by upper and lower polepieces 12 and so mounted between two similar coil-and-yoke assemblies each having upper and lower polepieces 15 co-operating with respective armature polepieces to define four air gaps 17 . . . 20 as to be rectilinearly displaceable, and a magnetic flux produced by the magnet divides into two fluxes # 1 , # 2 , each passing through a respective coil-and-yoke assembly, whilst a third magnetic flux # 3 generated upon energization of the coil-and-yoke assemblies to effect the displacement 21 flows through both such assemblies, the four air gaps and the armature polepieces but not through the armature magnet. The latter may be either a permanent magnet or an electromagnet, the assembly coils 16 are in series, and in other embodiments the polepieces and air gaps are constructed to produce particular characteristics. The motor is applicable to pressure, weight, acceleration, torque and dynometer measuring instruments, and to hydraulic and pneumatic valve positioners.