Abstract: A method and apparatus for detecting electromagnetic noise generated by an arc and controlling a power supply that powers the arcs. In an embodiment of the invention, the apparatus includes an arc detection circuit and a power supply control circuit. The arc detection circuit includes an antenna and a single shot timer. Electromagnetic noise generated by an arc is received by the antenna and activates the single shot timer, which causes the power supply control circuit to interrupt the power supply powering the arc for a predetermined length of time. A microprocessor can be used together with, or instead of, the single shot timer.

Abstract: In a two-stage, electrostatic precipitator for extracting airborne particles, charged plates are electrically connected to each other and physically separated from each other by ferrite spacers so that an impedance of the spacers limits an amount of arc discharge current that will flow when an arc discharge occurs from one of the charged plates. Ferrite spacers can also be provided to electrically connect and physically separate grounded plates in the precipitator. In addition, aluminum spacers can be provided to adjust the impedance of the series of spacers through which an arc discharge current flows, so that the current is a minimum necessary amount for an arc detection circuit to detect.

Abstract: The electrostatic air cleaning system is mounted in a duct of a residential or commercial heating and cooling system to remove particles from the circulating air. The electrostatic air cleaning system includes an air flow sensor which turns the air cleaner off in response to the lack of air flow through the air duct. An air flow sensor circuit connected to the electrostatic air cleaner includes a thermistor which detects the lack of air flow in the duct and provides a signal in response to lack of airflow. The signal from the sensor causes the power supply to the electrostatic air cleaner to be disconnected when there is insufficient air flow through the air duct. The air flow sensor circuit is configured so that power will continue to be supplied to the electrostatic air cleaner from the power supply when the sensor is disabled for a variety of reasons.