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Current ratio device

  • US 4,841,236 A
  • Filed: 03/22/1988
  • Issued: 06/20/1989
  • Est. Priority Date: 03/22/1988
  • Status: Expired due to Term
First Claim
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1. A device for use in constructing an alternating current, current transformer, said device comprising(a) a first magnetic core,(b) a second magnetic core,(c) a measuring winding having Nm turns electromagnetically coupled with the first core but not with the second core,(d) a compensating winding having Nc turns electromagnetically coupled with both cores,(e) an amplifier having an input and an output,(f) said input being connected to receive the waveform across the measuring winding,(g) said output being connected to the compensating winding to provide a compensating currect Ic through the conpensating winding equal to a magnetizing current Iμ

  • required to magnetize the second core, and(h) said output being connected to the measuring winding to provide a measuring current Im through the measuring winding in a direction opposite to that of the compensating current and equal to ##EQU5## whereby, when primary and secondary windings are electromagnetically coupled with the cores to form an alternating current, current transformer and the secondary winding is connected to a burden, the magnetizing current Iμ

    for such transformer is provided by the device.

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