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Multiple speed pump electronic control system

  • US 4,686,439 A
  • Filed: 09/10/1985
  • Issued: 08/11/1987
  • Est. Priority Date: 09/10/1985
  • Status: Expired due to Fees
First Claim
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1. A control system for two speed fluid pump having a first electrical power input for operation at a first low speed and a second electrical power input for operation at a second, high speed, comprising:

  • means for automatically sensing one of a rate of flow and a pressure of a fluid expelled from said pump and providing a trip signal at a predetermined value of one of said rate of flow and pressure;

    an oscillator;

    a counter having a clock input coupled to said oscillator, a reset input coupled to said sensing means, and an output;

    a relay for selectively coupling said first and second electrical power inputs to a power supply, said relay having a winding coupled at a first end to a second power supply; and

    a drive transistor having a collector coupled to a second end of said winding, an emitter coupled to ground, and a base coupled to said output of said counter.

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