Robert T Guenther

US Patent:

47729988, Sep 20, 1988

Filed:

Feb 26, 1987

Appl. No.:

7/019031

Inventors:

Robert N. Guenther - Mount Holly NJ
Hardey Singh - Robinsville NJ

Assignee:

NWL Transformers - Bordentown NJ

International Classification:

H02M 7155
B03C 368

US Classification:

363128

Abstract:

A control system for controlling high power from an AC source for electrostatic precipitators. The AC power is gated both on and off during the same half-cycle of the AC sources. The gating off of the AC power occurs at a time substantially different from the time of the zero crossings of the AC source. The AC source may be gated on and off respectively before and after each peak to provide high voltage to the precipator electrodes while the period of such pulsing is kept short enough to prevent arcing. Additionally, the source may be gated on after one peak and gated off before the next peak, thereby providing high voltage to the electrodes without applying the peak voltage of the AC. Further in accordance with the invention, such gating may be performed using gate turn-off thyristors. The pulses may be symmetric about the peaks or about the zero-crossings of the source.