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Method and apparatus for electrical dynamic braking

  • US 5,361,022 A
  • Filed: 03/23/1993
  • Issued: 11/01/1994
  • Est. Priority Date: 03/23/1993
  • Status: Expired due to Term
First Claim
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1. A control and dynamic braking circuit for movable equipment comprising:

  • (a) a plurality of semiconductor switching devices for switching electrical current arriving from an alternating current electrical power source, said alternating current approximating a sine wave, said semiconductor switching devices each containing a gating input, a load-current input, and a load-current output, said semiconductor switching devices directly switching said electrical current to the equipment, wherein the load-current inputs of said semiconductor switching devices are directly connected to said alternating current electrical power source, and the load-current outputs of said semiconductor switching devices are directly connected to said equipment;

    (b) a first controller for determining one of a plurality of operating modes of the equipment, said operating modes comprising running, braking, and stop modes; and

    (c) a second controller for individually selecting the gating input of each of the plurality of semiconductor switching devices at time intervals consistent with placing said semiconductor switching devices in one of a conducting and non-conducting mode, so as to operate said equipment in one of said operating modes, said second controller, during a running mode, selecting the gating inputs of only a first group of the plurality of semiconductor switching devices to conduct electrical current to the equipment during each positive half-cycle of the sine wave of the alternating current, and selecting the gating inputs of only a second group of the plurality of semiconductor switching devices to conduct electrical current to the movable equipment during each negative half-cycle of the sine wave of the alternating current.

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