GB587179A - Voltage regulating system - Google Patents

Abstract

587,179. Automatic voltage regulators. STANDARD TELEPHONES & CABLES, Ltd. Aug. 1, 1944, No. 14675. Convention date, Aug. 31, 1943. [Class 38 (iv)] In a rectified output voltage regulator, a selenium plate rectifier RB is connected to the secondary 9 of a constant voltage input transformer CUT through an auto-transformer AT in series with the A.C. winding 14 of a saturable core transformer SC. The rectifier supply voltage is regulated in response to load conditions by coils 25, 26, 27, 28 on the transformer SC energized by the D.C. output of the rectifier so as to vary the reactance of winding 14. The coils 27, 28 are arranged in shunt relation to the load to provide additional regulation to compensate for the non-correspondence of the magnetizing and voltdrop curves of the regulating means and are brought into operation by a relay circuit when the regulation of the series coils 25, 26 becomes inadequate. The said relay circuit comprises a marginal voltage relay 37 connected across the load and having high and low voltage contacts H, L. For a falling voltage, a relay 35 is first operated through conductor 32 and relay 33 to connect coils 27, 28 in circuit through a resistor 36. For a further decrease in voltage, resistor 36 is short-circuited by a relay, 42 and on the voltage decreasing still further, an alarm circuit 48 is energized by a relay 40. For an increasing voltage the reverse occurs through conductor 45 until all the regulation is left to coils 25, 26, after which a further increase in voltage causes an alarm circuit to be energized by a relay 38. A battery B may be charged on the output leads, a higher E.M.F. for this purpose being obtained by operating a push-button 50 which, through the medium of a multiple switch contactor 34, changes a tap on the auto-transformer from c to d at the same time closing a circuit 52 for a lamp charge indicator and short-circuiting windings 14, 25, 26, 27, 28 to remove the automatic regulation control. The auto-transformer is also provided with taps a and b which are used in accordance with the ageing of the rectifier plates and eliminated when the plates are fully aged.