patent number 5734543
A solenoid device, for example in an electrical contactor system, is provided for use with an alternating current power source. An electrical contactor includes an electromagnetic coil assembly configured to generate a non-zero effective magnetic force in response to an alternating current signal applied across the coil assembly. A switch proximate the coil assembly is configured to operate responsively to the effective magnetic force. A wave shaping device is configured to introduce a direct current component to an alternating current signal provided by the alternating current power source and to output at least part of the alternating current signal modified by the direct current component across the coil assembly.
Clemson University (Clemson, SC)