Electrostatic voltage control circuit
AssigneeChampion Spark Plug Company
InventorsRichard A. Moser, J. Thomas Schaffer, Richard Weinstein
Life of this patent
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Abstract
An improved control circuit for protecting a high voltage DC electrostatic system from arcing by removing the high voltage from the electrostatic system under incipient arcing conditions. A signal having a voltage proportional to the instantaneous high voltage current in the electrostatic system is established. DC components and unwanted noise and unwanted AC components are removed from the signal to leave only signal components relating to the rate of change of the current in the high voltage system and information indicative of incipient arcing conditions. When the remaining signal exceeds a predetermined reference level, high voltage is removed from the electrostatic system.
Claims10
A control circuit for a high voltage DC power supply for an electrostatic system comprising means for generating a low voltage first signal proportional to the instantaneous high voltage current in the electrostatic system, such first signal including information on any incipient arcing condition in the electrostatic system, filter means for removing the DC component from such first signal to produce an AC second signal including the incipient arcing information, means for removing unwanted noise from such second signal to produce a third signal having a magnitude proportional to the rate of change of the high voltage current in the electrostatic system and including voltage impulses proportional to instantaneous current impulses in the high voltage electrostatic system due to incipient arcing, and means responsive to such third signal exceeding a predetermined voltage for removing high voltage from the electrostatic system prior to the occurrence of arcing.
A control circuit for a high voltage DC power supply for an electrostatic system comprising means for generating a low voltage signal proportional to the instantaneous high voltage current in the electrostatic system, such signal including an AC ripple component and information on any incipient arcing condition in the electrostatic system, coupling capacitor means for removing the DC component from such first signal to produce an AC second signal including the incipient arcing information, means for providing a predetermined DC offset to such second signal, differential amplifier means having two inputs, a diode rectifier, means applying such offset second to one amplifier input and through said diode to the other amplifier input, said differential amplifier means removing AC ripple from such offset second signal to produce a third signal having a magnitude proportional to the instantaneous rate of change of the high voltage current in the electrostatic system, filter means for removing DC from such third signal, means for comparing such filter third signal with a predetermined reference voltage to establish a fourth signal when such filtered third signal exceeds such reference voltage, and means responsive to such fourth signal for removing high voltage from the electrostatic system.
Dependencies are inferred from the claim text.