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Excitation device for electromagnetic actuator

  • US 5,045,766 A
  • Filed: 05/23/1990
  • Issued: 09/03/1991
  • Est. Priority Date: 05/30/1989
  • Status: Expired due to Fees
First Claim
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1. A device for the electrical excitation of the coil or coils of an electromagnetic actuator, said device capable of causing a shift of said actuator in either direction, said device comprising a bridge consisting of two pairs of transistors, said bridge electrically connected to and capable of directly supplying electrical current to said coil(s) in either direction to obtain said shift of said actuator in either direction, said device further comprising means for measuring an error voltage, said error voltage being the difference between a reference voltage representing the current to be applied to said coil(s) and a voltage proportional to a current actually flowing through said coil(s), said error voltage consisting of an absolute value and a sign positive or negative;

  • said device further comprising means which, in response to one sign of said error voltage, turns off a first pair of said two pairs of transistors of said bridge and turns entirely on one transistor of a second pair of said two pairs of transistors, while simultaneously the other transistor of said second pair of transistors is caused to operate in a substantially linear mode, causing a current proportional to said error voltage to flow through said coil(s) in a first direction, and, conversely, in response to the opposite sign of said error voltage, turns off said second pair of said two pairs of transistors of said bridge and turns entirely on one transistor of said first pair of said two pairs of transistors, while simultaneously the other transistor of said first pair of transistors is caused to operate in a substantially linear mode, causing a current proportional to said error voltage to flow through said coil(s) in a second direction.

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