Solid state pump control and protection system
First Claim
Patent Images
1. A pump control system comprising:
- a synchronous phase detector for generating a first output signal related to a phase shift between an AC current signal supplied to a pump and a voltage signal supplied to the pump, the first output signal comprising a full cycle of the voltage signal as modified by the polarity of the amplitude of the AC current signal, the synchronous phase detector comprising a first operational amplifier for generating the first output signal; and
a switch means for receiving polarity information about the AC current signal and for adjusting the gain of the first operational amplifier in response to the polarity information;
a filter means for generating a filtered signal derived from the first output signal;
a comparator means for generating a second output signal based on a comparison of the filtered signal to a reference value;
a logic means for receiving the second output signal and generating a control signal; and
a relay means for turning power to the pump on or off in response to the control signal.
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Abstract
A pump control and protection system comprised of an analog module and a digital module. The analog module includes a synchronous phase detector, a pressure transducer and an over voltage/under voltage circuit. The synchronous phase detector determines the phase angle between a current signal supplied to a water pump and a voltage signal supplied to the pump. The output of the phase detector is directed to a programmable array logic device in the digital module and used to activate a solid state relay that controls the power supplied to the pump. The water pressure in the system is displayed on a digital display.
146 Citations
25 Claims
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1. A pump control system comprising:
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a synchronous phase detector for generating a first output signal related to a phase shift between an AC current signal supplied to a pump and a voltage signal supplied to the pump, the first output signal comprising a full cycle of the voltage signal as modified by the polarity of the amplitude of the AC current signal, the synchronous phase detector comprising a first operational amplifier for generating the first output signal; and a switch means for receiving polarity information about the AC current signal and for adjusting the gain of the first operational amplifier in response to the polarity information; a filter means for generating a filtered signal derived from the first output signal; a comparator means for generating a second output signal based on a comparison of the filtered signal to a reference value; a logic means for receiving the second output signal and generating a control signal; and a relay means for turning power to the pump on or off in response to the control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A water pump control system comprising:
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a current transformer means for extracting a first current signal from a first electrical line that supplies power to a water pump; a current detector means for processing the first current signal to yield a second current signal whose amplitude is related to the sign of the amplitude of the first current signal; a synchronous phase detector means for generating a first output signal related to a phase shift between the second current signal and a voltage signal taken from a second electrical line that supplies power to the pump, the first output signal comprising a full cycle of the voltage signal as modified by the second current signal, the synchronous phase detector comprising a first operational amplifier for generating the first output signal; and a switch means for receiving polarity information about the second current signal and for adjusting the gain of the first operational amplifier in response to the polarity information; a filter means for generating a filtered signal derived from the first output signal; a comparator means for comparing the filtered signal to a reference value and generating a second output signal based on the comparison of the filtered signal to the reference value; a logic means for processing the second output signal to yield a control signal; and a relay means for turning power to the pump on or off in response to the control signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21)
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20. A water pump control system comprising:
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a current transformer means for extracting a first current signal from a first electrical line that supplies power to a submersible water pump in the one-tenth to three horsepower power range; a current detector means for processing the first current signal to yield a second current signal having the same phase as the first current signal but having a square wave amplitude; a switch means for receiving the second current signal; a synchronous phase detector comprised of an operational amplifier that generates a first output signal by using the second current signal to modify the amplitude of a full cycle of a voltage signal taken from a second electrical line that supplies power to the water pump, the gain of the operational amplifier being varied by the switch means in response to the second current signal; a filter means for generating a filtered signal derived from the first output signal; a comparator means for comparing the filtered signal to a reference value and generating a second output signal based on the comparison of the filtered signal to the reference value; a logic means for processing the second output signal to yield a control signal; and a solid state relay means for turning power to the pump on or off in response to the control signal only at zero crossings of the voltage signal. - View Dependent Claims (22)
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23. A method for detecting mechanical problems in a pump comprising the steps of:
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a. using inductive coupling to extract a current signal from a first conductor that supplies electrical current for a pump; b. using inductive coupling to extract a voltage signal from a second conductor that supplies electrical current for the pump; c. inputting a full cycle of the voltage signal into a synchronous phase detector, the synchronous phase detector comprising an operational amplifier and a switch means for receiving polarity information about the current signal and for causing a gain adjustment in the operational amplifier in response to the polarity information; d. generating a first output signal from the operational amplifier comprised of the full cycle of the voltage signal as modified by the gain adjustment caused by the switch means; e. generating a second output signal derived from the first output signal; and f. interrupting the flow of electrical current to the pump when the second output signal moves outside of a predetermined range. - View Dependent Claims (24)
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25. A method for detecting a low liquid condition in a pump comprising the steps of:
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a. using inductive coupling to extract a current signal from a source of AC electrical current for a pump that pumps a liquid; b. using inductive coupling to extract a voltage signal from a source of AC electrical current for the pump; c. inputting the current signal into a switch means for causing gain adjustments in an operational amplifier in response to polarity information contained in the current signal; d. generating a first output signal from the operational amplifier comprised of a full cycle of the voltage signal modified by the gain adjustments caused by the switch means; e. generating a second output signal derived from the first output signal; f. interrupting the source of AC electrical current to the pump when the second output signal moves outside of a predetermined range, thereby indicating a low volume of the liquid; g. starting a timer that measures a first interval of time; h. restoring the source of AC electrical current to the pump after expiration of the first interval of time; and i. repeating steps a-f.
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Specification