Pump controller

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 6534947
APP PUB NO 20020093306A1
SERIAL NO

09760276

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ATTORNEY / AGENT: (SPONSORED)

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Abstract

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A method and apparatus for controlling an electric motor pump. The method includes the acts of providing an AC power signal having a positive half cycle and a negative half cycle, measuring the voltage of the AC power signal and generating a first two-state output signal that is in a logic high state when the measured voltage is on the positive half cycle and that is in a logic low state when the measured voltage is on the negative half cycle, and measuring the current of the AC power signal and generating a second two-state output signal that is in logic high state when the measured current is on the positive half cycle and that is in a logic low state when the measured current is on the negative half cycle. The method also includes determining a time difference between the first and second two-state output signals, calculating a phase difference based on the time difference, comparing the phase difference to a predetermined threshold value, opening a switch if the determined phase difference is equal to or greater that the predetermined threshold value, and, after the switch is opened, closing the switch after a predetermined amount of time has elapsed.

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Patent Owner(s)

  • LITTELFUSE, INC.;STA-RITE INDUSTRIES, INC.

International Classification(s)

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Johnson, Steven A Hartland, WI 65 2930
Larson, Kip M Rapid City, SD 7 135
Walker, Dee R Rapid City, SD 2 125

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