GB970617A - Improvements in current regulators - Google Patents

Abstract

970,617. Automatic current control. ZAVODY PRUMYSLOVE AUTOMATISACE, NARODNI PODNIK. Aug. 27,1962 [Aug. 31, 1961], No. 32756/62. Heading G3R. An output transformer 1 is controlled by an error signal from a comparison and amplifying device 8 to provide a constant current to a load 9, e.g. an airport lighting system, which is fed, over a current transformer 6, from the secondary circuit of the transformer 1, a control signal dependent on load current variations being fed to the device 8 over a rectifier 7. It is stated that for systems of this kind the output current tends to drop when the output voltage exceeds 50% of its rated maximum; to compensate for this, a further resistor 4 and a choke 3 are connected as shown to an auxiliary winding 2 of the output transformer, whereby the control signal is modified at higher output voltages. The arrangement is such that the choke 3 saturates at output voltages exceeding 50% of the rated maximum, so that a voltage drop occurs across the resistor 4. This voltage drop opposes the voltage across a resistor 5 connected across the secondary of transformer 6 so that the control signal to the device 8 decreases in value as the output voltage of the system increases. The output error signal from the device 8 is thus increased, and the output from transformer 1 rises to counteract the decrease in load current which would otherwise occur.