Copyright © Philip M. Parker, INSEAD. Terms of Use.
| Year | Description |
| 1996 | Invention patented by G. Stephen Perreira on May 5th, 1996. Abstract: The DC actuator control circuit with voltage compensation, current control and fast dropout period employs an electronic chopper incorporating an oscillator having a variable duty cycle controlled by sensing of coil current. Coil current is sampled through a series resistor by a feedback amplifier which increases or decreases the period in which the switch for the coil circuit remains on to sustain average coil current at the desired MMF. A threshold detector provides an initial triggering signal to initiate operation of the actuator and the control circuit responsive to a predetermined source voltage and a gate signal generator responds to the triggering signal with a time constant sufficient to drive the coil through a pickup interval. Inrush current is limited by the oscillator through sensing of coil current. A dropout switch for opening the sustaining current return circuit which opens upon removal of source voltage provides a high impedance for rapid current drain from the coil thereby eliminating regeneration effects. |
| Source: selected by the editor from original sources. | |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
