GB635199A - Improvements in regulators for dynamo electric machines - Google Patents

Abstract

635,199. Automatic voltage control systems. NEWTON, F. Aug. 10, 1945, No. 20612. [Class 38 (iv)] Voltage regulating circuit connected across the terminals of a variable-speed alternator which feeds one or more identical parallel connected load units each in the form of a resistance in series with a reactance is so devised as to possess impedance of the same character and proportion as that of each of the load units in order to maintain a constant voltage across the resistance portion of each of the load units. As shown a motor generator 1, 2 supplies fluorescent lamps 7, each connected in series with a capacitance 9 and in parallel with a choke 8 designed to be saturated by a fraction of the supply voltage. In the regulator circuit a condenser 11 is in series with a bridge rectifier across the alternator terminals and it is arranged that a ratio, the same as that in each of the lamp circuits, exists between the reactance due to the condenser 11 and the circuit ohmic resistance according to the setting of coarse and fine variable resistors 13, 14 which are in series with the control winding 6 of the carbon pile 4 across the output of the bridge rectifier. If there is a departure from the normal operating frequency the resultant change in excitation of the control winding 6 operates the carbon pile 4 to effect the required change in excitation of the alternator 2 so that the voltage generated increases or decreases to restore the normal operating current through the winding 6 and each of the lamp circuits and therefore the rated volts across the lamps 7. The regulator circuits shown may be modified in that the condenser 11 may be in series with the resistors 13, 14 with the bridge rectifier connected across the latter and the control winding 6 across the output of the bridge rectifier. The lamp circuits may each comprise simply the lamp 7 in series with a choke in which case the regulator circuit is modified accordingly. The regulator 4, 6 may be constructed as described in Specification 544,170.