GB731059A - Improvements relating to magnetic discriminators - Google Patents

Abstract

731,059. Magnetic amplifiers. WESTING- HOUSE BRAKE & SIGNAL CO., Ltd., and KING, K. G. June 24, 1953 [July 17, 1952], No. 18086/52. Class 40 (4). [Also in Group XXXV] A variable inductor comprises an A.C. winding wound, to prevent coupling with the D.C. windings, in two series connected halves 10, 11 on the central limb, split into two halves 2, 3 of a magnetic core, which has two outer limbs 1, 4 carrying D.C. windings 9, 12 connected in series as shown, or alternatively in parallel. Limb 1 is of a saturable magnetic material such as that sold under the Registered Trade Mark " Mumetal," which saturates before the rest of the core, and has a # I curve such as 8 in Fig. 2, while limb 4, which has an airgap 7, has a linear # I relationship 22. When the D.C. through windings 9, 12 has the value corresponding to the common point of curves 8, 22, the flux in limbs 1 and 4 is equal and none passes through the central limb. When the D.C. varies in either direction from this value, the two fluxes differ by an amount which passes through the central limb and varies the inductance of windings 10, 11. Fig. 1 shows a circuit for stabilizing the voltage across load 21 supplied from rectifier 19 in which the departure of the load voltage from the required value varies the inductance of windings 10, 11, which are energized from an A.C. supply, and the consequent change in current through these windings is used, through amplifier 18 to control the rectifier in such a way as to restore the load voltage to the desired value. This value may be such as to produce current i, Fig. 2, in the windings 9, 12 differing from the value corresponding to the intersection point of curves 8, 22, to allow for discrimination between decrease and increase from the required value. Specification 730,080, [Group XL (b)], is referred to.