Automatic current overload protection circuit for electrostatic precipitator power supplies

Claim 1

In an electrostatic precipitator power supply of the type having a ferroresonant transformer including a primary winding and a secondary winding, said primary winding configured to be coupled to a source of power, said secondary winding adapted to supply high voltage to an ionizer and collecting cell in the precipitator, an automatic current overload protection circuit comprising: a. switch means in series with the primary winding of the transformer for allowing current flow therethrough from the source of power when said switch means is activated under normal operating conditions and inhibiting current flow therethrough when said switch is deactivated during an overload current condition; b. a tertiary winding in association with the transformer, said tertiary winding developing an output voltage which decreases as the current supplied by said transformer increases; and c. sensing means connected to said tertiary winding for deactivating said switch means to inhibit current flow through the primary winding of the transformer when said output voltage developed by said tertiary winding is less than or equal to a predetermined voltage threshold level.