Apparatus and method for calibrating a motor monitor by reading and storing a desired value of the power factor
First Claim
1. In an improved electric motor monitor, the monitor capable of connection to a supply of electrical energy for the motor, having;
- a microcomputer for measuring the power factor of a voltage applied to said motor and a current flowing to said motor, for storing a desired value of power factor, for comparing a measured value of power factor with said desired value of power factor, and for disconnecting said motor from said supply of electrical energy if said measured value of said power factor differs from said desired value of power factor by an amount that exceeds a predetermined amount,the improvement comprising;
means for operating said motor while driving a desired load;
means for commanding said microcomputer to measure a power factor of said voltage applied to said motor and said current flowing to said motor while said motor is driving said desired load; and
,means for storing said measured value of said power factor, measured while said motor is driving said desired load, as said desired power factor.
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Accused Products
Abstract
A monitor for an electric motor, the monitor capable of connection to a supply of electrical energy for the motor, has a microcomputer for measuring the power factor of a voltage applied to the motor and a current flowing to the motor, for storing a desired value of power factor, for comparing a measured value of power factor with the desired value of power factor, and for disconnecting the motor from the supply of electrical energy if the measured value of the power factor differs from the desired value of power factor by an amount that exceeds a predetermined amount. Further, the monitor has means for operating the motor while driving a desired load; means for commanding the microcomputer to measure a power factor of the voltage applied to the motor and the current flowing to the motor while the motor is driving the desired load; and, means for storing the measured value of the power factor, measured while the motor is driving the desired load, as the desired power factor. The monitor may control a motor driving a pump for a fluid system. The monitor may include: a pressure sensitive mechanical switch; means for measuring motor current, voltage applied to the motor, time intervals during which the motor is energized, and the rapidity of cycle time of the motor in order to disconnect the motor from the source of electrical energy to prevent damage to the motor.
118 Citations
10 Claims
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1. In an improved electric motor monitor, the monitor capable of connection to a supply of electrical energy for the motor, having;
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a microcomputer for measuring the power factor of a voltage applied to said motor and a current flowing to said motor, for storing a desired value of power factor, for comparing a measured value of power factor with said desired value of power factor, and for disconnecting said motor from said supply of electrical energy if said measured value of said power factor differs from said desired value of power factor by an amount that exceeds a predetermined amount, the improvement comprising; means for operating said motor while driving a desired load; means for commanding said microcomputer to measure a power factor of said voltage applied to said motor and said current flowing to said motor while said motor is driving said desired load; and
,means for storing said measured value of said power factor, measured while said motor is driving said desired load, as said desired power factor.
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2. In an improved electric motor monitor, the monitor capable of connection to a supply of electrical energy for the motor, having:
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a microcomputer for measuring the power factor of a voltage applied to said motor and a current flowing to said motor, for storing a desired value of power factor, for comparing a measured value of power factor with said desired value of power factor, and for disconnecting said motor from said supply of electrical energy if said measured value of said power factor differs from said desired value of power factor by an amount that exceed a predetermined amount, the improvement comprising; said microcomputer periodically measuring the time interval between the zero crossing of a waveform of said voltage applied to said motor and the zero crossing of a waveform of said current flowing in said motor to determine the value of the power factor, and the power factor is compared with the desired power factor; means for operating said motor while driving a desired load; means for commanding said microcomputer to measure a power factor of said voltage applied to said motor and said current flowing to said motor while said motor is driving said desired load; and non-volatile memory means for storing said measured value of said power factor, measured while said motor is driving said desired load, as said desired power factor; at least one illuminating device externally visible and operatively connected having coded multiple illuminating states to indicate the operating state of the motor; a power relay which interrupts motor current on microcomputer command if the power factor exceeds the desired power factor by a first predetermined amount, and if the power factor is less than the desired power factor by a second predetermined amount. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9)
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10. A pump and electric motor monitor for an AC electric motor driving a pump in a fluid system, the monitor capable of connection to a supply of AC electrical energy for the motor, comprising:
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a microcomputer for measuring the power factor of a voltage applied to said motor and a current flowing to said motor, for storing a desired value of power factor, for comparing a measured value of power factor with said desired value of power factor, and for disconnecting said motor from said supply of electrical energy if said measured value of said power factor differs from said desired value of power factor by an amount that exceeds a predetermined amount, means for operating said motor while driving a desired load; means for commanding said microcomputer to measure a power factor of said voltage applied to said motor and said current flowing to said motor while said motor is driving said desired load; non-volatile memory means for storing said measured value of said power factor, measured while said motor is driving said desired load, as said desired power factor; a pressure sensitive switch having terminals connected to said supply of AC electrical energy and terminals connected to said AC motor for maintaining a pressure in said fluid system within desired upper and lower pressure limits; means for monitoring motor current and for disconnecting said motor from said supply of AC electrical energy if said current becomes outside of desired current limits; means for monitoring voltage applied to said motor and for disconnecting said motor from said supply of AC electrical energy if said voltage becomes outside of desired voltage limits; a housing containing said microcomputer, solid state components, and said pressure sensitive switch, thereby providing a fluid system monitor capable of maintaining pressure within desired limits, capable of disconnecting said motor is said motor looses its load, capable of disconnecting said motor if said current becomes outside of desired current limits, capable of disconnecting said motor if said voltage becomes outside of desired upper and lower limits, and contained within said housing.
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Specification