Abstract: An electrostatic precipitator is supplied with a d-c voltage of variable level upon which is superimposed a series of voltage pulses. For each voltage pulse, the difference between a positive current-time area and a negative current-time area beneath a current-voltage curve is determined and maximized by changing the pulse amplitude, pulse width, pulse repetition frequency and/or the rate of pulse rise. In addition, the d-c voltage is controlled to have a value at a point of maximum slope of the function of precipitator current with respect to the magnitude of the d-c voltage.

Abstract: An electrostatic precipitator is fed high voltage pulses by a pulse generating circuit including a high voltage transformer and a first thyristor switch connected in series with a primary winding of the transformer. Magnetic saturation of the core of the high voltage transformer is prevented by recurrently short circuiting the primary winding of the transformer by means of a second thyristor switch connected in parallel to the primary winding. The second thyristor switch is closed for a period of time extending from a first instant following a high voltage pulse crest to a second instant at or before the start of a pulse generating cycle subsequent to the pulse crest.