GB981147A - Improvements in the automatic voltage control of electrical precipitators - Google Patents

Abstract

981,147. Automatic control of electrical precipitators. H. BRANDT. and A. KRITZLER, [trading as APPARATEBAU ROTHEMUHLE BRANDT, and KRITZLER], July 25, 1963 [July 28, 1962], No. 29529/63. Heading G3R. [Also in Division H2] In an electrical precipitator, a voltage decrease caused by flash-overs between the electrodes is used to determine the variation in voltage which is needed either to increase or decrease that applied across the electrodes to ensure optimum operating conditions. As shown, an electrical precipitator 12 is supplied from an A.C. source R, S by way of a contactor 2<SP>1</SP>, a magnetic amplifier 15, a transformer 10 and a rectifier 11. Voltage and current variations in the precipitator are detected by transformers 36 and 3 connected to a circuit V the output from which moves an aluminium plate F, the arrangement being such that the output from an oscillator circuit 5 including transistors T1, T2 and reactance coils LB, LK associated with the plate F, is proportional to the voltage decrease caused by flash-overs. The output from circuit 5 is applied as a charging current to an integrating circuit, constituted by capacitors K1, K4 and resistor R1, which is simultaneously discharged at a rate determined by adjustment of K4 and R1. Any output from the integrator circuit at lines 8 and 9 is applied over magnetic amplifiers 13 and 14 to the magnetic amplifier 15 the output winding of which applies the necessary increase or decrease in operating voltage to the transformer 10, until the charging and discharging of the integrator circuit reaches equilibrium.