GB1206013A - Magnetic slave compass with an alarm device - Google Patents

Abstract

1,206,013. Magnetic amplifier circuits. N1- EUWE ROTTERDAMSCHE INSTRUMENTFABRIEK OBSERVATOR N.V. 3 Jan., 1968 [6 Jan., 1967], No. 405/68. Heading H3B. [Also in Divisions G1 and H2] In the remote indication of a flux-gate compass the double frequency output from the rotor coil 4 (Fig. 1) of a slave member is amplified in a magnetic amplifier 5 and used to energize an induction motor 6, fed with the single frequency voltage on its reference winding 7, to drive the rotor and reduce the output from coil 4 to zero. The double frequency signal from coil 4 is amplified by transistor T 1 (Fig. 6) and fed to the control windings 27, 28 of transductor TD 2 , and control windings 29, 30 of transductor TD 3 , the pairs of windings being connected in series and wound in opposite directions on the cores of the transductors. The main windings 31-34 of the transductors are connected via diodes 35-38 to one terminal of the single frequency A.C. supply and via the field windings 8, 9 of the motor 6 to the other terminal. The circuit is arranged so that for zero input signal the outputs from the two transductors are equal, and the resultant torque on motor 6 from the currents in windings 8; 9 is zero. When a signal is developed in coil 4, the point in the half-cycles at which the cores of the transductors saturate is varied, so that the outputs are unequal, an input signal of one phase-sense causing the output from transductor TD 2 to increase and that from transductor TD 3 to decrease, and vice versa. This determines the direction of rotation of motor 6, to restore coil 4 to alignment with the direction of the resultant field produced by the stator coils 3.