Automatic reset current cut-off for an electrostatic precipitator power supply

Claim 1

In a two stage electrostatic precipitator air cleaner of the type having an ionizer for charging airborne particles, a collecting cell for collecting the charged particles and power supply means responsive to a primary voltage for providing relatively high voltage to said ionizer and said cell comprising a ferroresonant transformer having a primary winding, a secondary winding for producing relatively high voltage, and means utilizing said high voltage to charge said ionizer and said collecting cell, the improvement in combination therewith comprising automatic electronic protection circuitry for said power supply including: electronic switch means connected in series with said transformer primary winding for permitting current flow through the primary winding upon application of an enabling signal to said switch means; timing means shunting said switch means for producing said enabling signal a predetermined time after primary voltage is initially applied to said power supply or said switch means operates to inhibit current flow through said primary winding; attenuator means for producing a sense voltage representative of the voltage applied to said ionizer; comparison means for comparing said sense voltage to a reference voltage to produce an inhibit signal when said sense voltage falls outside normal operating ranges; and means responsive to said inhibit signal for inhibiting operation of said switch means to prevent current flow through said transformer primary winding to shut down power supply operation.