Patent ID: 6968859

Claim:
An electromagnetic operating device constituting an electromechanical transducer for exerting a mechanical output on a valve element against a spring force preloaded on the valve element, comprising: a solenoid coil including a plurality of split coils which are electrically independent from each other; a magnetic core structure including a fixed core, a movable core and a yoke, said core structure being assembled with said solenoid coil in such a way as to form a magnetic path loop through which magnetic fluxes produced from the split coils pass in common; an excitation controller for selectively switching and controlling the excitation to each of the split coils; and a transmission mechanism for transmitting to the valve element the mechanical output on the basis of the displacement of the movable core magnetically attracted to the fixed core when any one or more of the split coils are excited, wherein the excitation controller includes a current amplifier for producing an excitation current of magnitude corresponding to a current command value externally supplied.