Apparatus for measuring electrical power consumption

• US 6,483,291 B1
• Filed: 05/26/2000
• Issued: 11/19/2002
• Est. Priority Date: 05/26/2000
• Status: Expired due to Term

• Current Assignee: Ranko IP Series of Ranko, LLC
• Original Assignee: Chander P. Bhateja, Rajiv K. Bhateja
• Inventors: Bhateja, Chander P., Bhateja, Rajiv K.
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): HOLLINGTON, JERMELE M
• Application Number:
  US09/579,687
• Time in Patent Office: 907 Days
• Field of Search: 324/142, 324/107, 324/74, 324/117.R
• US Class Current: 324/142
• CPC Class Codes: G01R 21/06 by measuring current and voltage G01R21/08 - G01R21/133 take precedence
• CPC Class Codes: G01R 22/00 Arrangements for measuring time integral of electric power or current, e.g. electricity meters

Abstract

An apparatus for measuring electrical power consumption. An apparatus for measuring electrical power consumption is provided. The total power is obtained by multiplying the instantaneous voltage of the load by the instantaneous current of the load and summing the results of multiple phases. The total power voltage is calibrated to the full scale of the power meter for display to the operator. The power meter digitally displays the output in operator selectable measurement units and on a rapid response bar graph representing the proportion of full scale. Additionally, the power meter provides a current output and both scaled and unscaled voltage outputs representing the total power consumption, high and low trip settings, a peak power hold feature, and a scaling feature to allow precise measurements at for power levels less than the full scale rating of the power meter. Finally, the power meter can be connected to external devices for monitoring or control.

Claims

1. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one current sensor for producing a first voltage proportional to a magnetic field generated by a current conducted in the power supply line connected to the electrical load;

at least one voltage attenuation circuit for producing a second voltage proportional to a voltage on the power supply line connected to the electrical load;

at least one multiplier in electrical communication with said at least one current sensor and said at least one voltage attenuation circuit, said at least one multiplier multiplying said first voltage by said second voltage to produce a phase power voltage proportional to an instantaneous amount of power consumed by the electrical load;

an adder in electrical communication with said at least one multiplier, said adder summing all said phase power voltages to produce a total power voltage;

an analog-to-digital converter in electrical communication with said adder, said analog-to-digital converter converting said total power voltage to an output signal;

at least one display in electrical communication with said analog-to-digital converter, said at least one display displaying at least said output signal in a human readable format; and

a power supply for supplying power to said meter.

2. The power meter of claim 1 further comprising a unit converter in electrical communication between said analog-to-digital converter and said at least one display, said unit converter scaling said output signal to a predetermined unit of measurement.

3. The power meter of claim 1 further comprising at least one interface in electrical communication with said adder for communicating with an external device.

4. The power meter of claim 3 wherein said at least one interface is selected from the group consisting of, but not limited to, a scaled voltage output, an unscaled voltage output, a differential voltage output, a current output, a trip indicator output, and a control input.

5. The power meter of claim 4 wherein said at least one interface simultaneously includes said scaled voltage output and said unscaled voltage output.

6. The power meter of claim 1 wherein said at least one current sensor is a Hall Effect sensor.

7. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one means for measuring a current and producing a first voltage corresponding to the current conducted in the power supply line connected to the electrical load;

at least one means for measuring a supply voltage on the power supply line connected to the electrical load and producing a second voltage corresponding to the supply voltage;

means for calculating an analog total power voltage from all said first voltages and all said second voltages;

means for generating a digital output signal from said means for calculating a total power voltage; and

means for displaying said digital output signal in a human readable format.

8. The power meter of claim 7 wherein said means for displaying said output signal graphically displays said scaled voltage proportionally with respect to a full scale of a selected range.

9. The power meter of claim 7 further comprising a means for digitizing said total power voltage.

10. The power meter of claim 7 further comprising a means for scaling said output signal to a predetermined unit of measurement.

11. The power meter of claim 7 further comprising at least one means for communicating with an external device.

12. The power meter of claim 11 wherein said at least one means for communicating with an external device is selected from the group consisting of, but not limited to, a scaled voltage output, an unscaled voltage output, a differential voltage output, a current output, a trip indicator output, and a control input.

13. The power meter of claim 12 wherein said at least one means for communicating with an external device simultaneously includes said scaled voltage output and said unscaled voltage output.

14. The power meter of claim 7 further comprising

a means for storing a reference value of said output signal; and

a means for producing a differential voltage representative of a voltage differential between an instantaneous said output signal and said reference value.

15. The power meter of claim 14 further comprising a means for scaling said differential voltage to a selected range as a scaled voltage.

16. The power meter of claim 14 further comprising a means for selectively displaying either of said output signal and said differential voltage.

17. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one current sensor for producing a first voltage proportional to a magnetic field generated by a current conducted in the power supply line connected to the electrical load;

at least one voltage attenuation circuit for producing a second voltage proportional to a voltage on the power supply line connected to the electrical load;

at least one multiplier in electrical communication with said at least one current sensor and said at least one voltage attenuation circuit, said at least one multiplier multiplying said first voltage by said second voltage to produce a phase power voltage proportional to an instantaneous amount of power consumed by the electrical load;

an adder in electrical communication with said at least one multiplier, said adder summing all said phase power voltages to produce a total power voltage;

a reference value comparator in electrical communication with said adder, said reference value comparator storing a reference value of said total power voltage and producing a differential voltage representative of a voltage differential between an instantaneous said output signal and said reference value;

a range amplifier in electrical communication with said adder and said reference value comparator, said range amplifier producing a scaled voltage equal to either of said total power voltage and said differential voltage scaled to a selected range;

a first display in electrical communication with said range amplifier, said first display displaying said scaled voltage proportionally with respect to a full scale of said selected range;

an analog-to-digital converter in electrical communication with said adder, said analog-to-digital converter converting said total power voltage to an output signal;

a peak detector in electrical communication with said analog-to-digital converter, said peak detector storing a maximum value of said output signal;

a source switch in electrical communication with said analog-to-digital converter for selectively displaying either of said output signal and said differential voltage;

a unit converter in electrical communication with analog-to-digital converter, said unit converter scaling said output signal to a predetermined unit of measurement;

a second display in electrical communication with said analog-to-digital converter, said second display displaying either of said output signal and said output signal maximum value in numeric format;

a high trip point detector in electrical communication with said adder;

a low trip point detector in electrical communication with said adder;

at least one adjustable delay in electrical communication with said high trip point detector and said low trip point detector, said at least one adjustable delay setting a length of time such that said high trip point detector and said low trip point detector provide an indication only when said total power voltage remains beyond a corresponding threshold value for a selected said length of time;

a plurality of output ports, each of said plurality of output ports in communication with one of said adder, said trip detector, and said range amplifier; and

a power supply for supplying power to said meter.

18. The power meter of claim 17 further comprising at least one interface in electrical communication with either of said adder and said range amplifier, said at least one interface providing digital bidirectional communication with an external device.

19. The power meter of claim 17 wherein said plurality of outputs includes a scaled voltage output and an unscaled voltage output.

20. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one means for measuring a current and producing a first voltage corresponding to the current conducted in the power supply line connected to the electrical load;

at least one means for measuring a supply voltage on the power supply line connected to the electrical load and producing a second voltage corresponding to the supply voltage;

means for calculating a total power voltage from all said first voltages and all said second voltages;

means for storing a reference value of said total power voltage and for producing a differential voltage representative of a voltage differential between an instantaneous said total power voltage and said reference value;

means for selectively passing either of said total power voltage and said differential voltage as a source signal;

means for digitizing said source signal as a digital output signal;

means for scaling said digital output signal to a predetermined unit of measurement;

means for scaling either of said source signal and said digital output signal to a selected range as a scaled voltage;

means for graphically displaying said scaled voltage proportionally with respect to a full scale of said selected range;

means for storing a maximum value of said digital output signal;

means for displaying at least digital output signal in a numeric format;

at least one means for determining when either of said source signal and said digital output signal remains beyond either of a high threshold value and a low threshold value for a selected period of time; and

a plurality of means for communicating with an external device, each of said plurality of communication means in communication with one of said calculation means, said trip point detection means, and said scaling means.

21. The power meter of claim 20 wherein said plurality of communication means includes at least one means for providing digital bidirectional communication with an external device.

22. The power meter of claim 20 wherein said plurality of communication means includes a scaled voltage output and an unsealed voltage output.

23. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one current sensor for producing a first voltage proportional to a magnetic field generated by a current conducted in the power supply line connected to the electrical load;

at least one voltage attenuation circuit for producing a second voltage proportional to a voltage on the power supply line connected to the electrical load;

at least one multiplier in electrical communication with said at least one current sensor and said at least one voltage attenuation circuit, said at least one multiplier multiplying said first voltage by said second voltage to produce a phase power voltage proportional to an instantaneous amount of power consumed by the electrical load;

an adder in electrical communication with said at least one multiplier, said adder summing all said phase power voltages to produce a total power voltage;

an analog-to-digital converter in electrical communication with said adder, said analog-to-digital converter converting said total power voltage to an output signal;

at least one display in electrical communication with said analog-to-digital converter, said at least one display displaying at least said output signal in a human readable format;

a range amplifier in electrical communication with said adder, said range amplifier scaling said total power voltage to a selected range as a scaled voltage; and

a power supply for supplying power to said meter.

24. The power meter of claim 23 further comprising a visual indicator in electrical communication with said range amplifier, said visual indicator displaying said scaled voltage proportionally with respect to a full scale of said selected range.

25. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one current sensor for producing a first voltage proportional to a magnetic field generated by a current conducted in the power supply line connected to the electrical load;

at least one voltage attenuation circuit for producing a second voltage proportional to a voltage on the power supply line connected to the electrical load;

at least one multiplier in electrical communication with said at least one current sensor and said at least one voltage attenuation circuit, said at least one multiplier multiplying said first voltage by said second voltage to produce a phase power voltage proportional to an instantaneous amount of power consumed by the electrical load;

an adder in electrical communication with said at least one multiplier, said adder summing all said phase power voltages to produce a total power voltage;

an analog-to-digital converter in electrical communication with said adder, said analog-to-digital converter converting said total power voltage to an output signal;

at least one display in electrical communication with said analog-to-digital converter, said at least one display displaying at least said output signal in a human readable format;

a peak detector in electrical communication between said analog-to-digital converter and said display, said peak detector storing a maximum value of said output signal; and

a power supply for supplying power to said meter.

26. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one current sensor for producing a first voltage proportional to a magnetic field generated by a current conducted in the power supply line connected to the electrical load;

at least one voltage attenuation circuit for producing a second voltage proportional to a voltage on the power supply line connected to the electrical load;

at least one multiplier in electrical communication with said at least one current sensor and said at least one voltage attenuation circuit, said at least one multiplier multiplying said first voltage by said second voltage to produce a phase power voltage proportional to an instantaneous amount of power consumed by the electrical load;

an adder in electrical communication with said at least one multiplier, said adder summing all said phase power voltages to produce a total power voltage;

an analog-to-digital converter in electrical communication with said adder, said analog-to-digital converter converting said total power voltage to an output signal;

at least one display in electrical communication with said analog-to-digital converter, said at least one display displaying at least said output signal in a human readable format;

at least one trip point detector in electrical communication with said adder, said at least one trip point detector indicating when said total power voltage crosses either of a high threshold value and a low threshold value; and

a power supply for supplying power to said meter.

27. The power meter of claim 26 wherein said at least one trip point detector includes an adjustable delay such that said at least one trip point detector provides an indication only when said total power voltage remains beyond either of a high threshold and a low threshold for a selected period of time.

28. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one current sensor for producing a first voltage proportional to a magnetic field generated by a current conducted in the power supply line connected to the electrical load;

at least one voltage attenuation circuit for producing a second voltage proportional to a voltage on the power supply line connected to the electrical load;

at least one multiplier in electrical communication with said at least one current sensor and said at least one voltage attenuation circuit, said at least one multiplier multiplying said first voltage by said second voltage to produce a phase power voltage proportional to an instantaneous amount of power consumed by the electrical load;

an adder in electrical communication with said at least one multiplier, said adder summing all said phase power voltages to produce a total power voltage;

an analog-to-digital converter in electrical communication with said adder, said analog-to-digital converter converting said total power voltage to an output signal;

at least one display in electrical communication with said analog-to-digital converter, said at least one display displaying at least said output signal in a human readable format;

a reference value comparator in electrical communication with said adder, said reference value comparator storing a reference value of said total power voltage and producing a differential voltage representative of a voltage differential between an instantaneous said output signal and said reference value; and

a power supply for supplying power to said meter.

29. The power meter of claim 28 further comprising a range amplifier in electrical communication with said reference value comparator, said range amplifier scaling said differential voltage to a selected range as a scaled voltage.

30. The power meter of claim 28 further comprising a source switch in electrical communication with said analog-to-digital converter for selectively displaying either of said output signal and said differential voltage.

31. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one means for measuring a current and producing a first voltage corresponding to the current conducted in the power supply line connected to the electrical load;

at least one means for measuring a supply voltage on the power supply line connected to the electrical load and producing a second voltage corresponding to the supply voltage;

means for calculating a total power voltage from all said first voltages and all said second voltages;

means for generating an output signal from said means for calculating a total power voltage;

means for displaying said output signal in a human readable format; and

means for scaling said total power voltage to a selected range as a scaled voltage output.

32. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one means for measuring a current and producing a first voltage corresponding to the current conducted in the power supply line connected to the electrical load;

at least one means for measuring a supply voltage on the power supply line connected to the electrical load and producing a second voltage corresponding to the supply voltage;

means for calculating a total power voltage from all said first voltages and all said second voltages;

means for generating an output signal from said means for calculating a total power voltage;

means for displaying said output signal in a human readable format; and

at least one means for determining when said output signal crosses either of a high threshold and a low threshold.

33. A power meter for measuring power consumption of an electrical load connected to a power supply line, said power meter comprising:

at least one means for measuring a current and producing a first voltage corresponding to the current conducted in the power supply line connected to the electrical load;

at least one means for measuring a supply voltage on the power supply line connected to the electrical load and producing a second voltage corresponding to the supply voltage;

means for calculating a total power voltage from all said first voltages and all said second voltages;

means for generating an output signal from said means for calculating a total power voltage;

means for displaying said output signal in a human readable format; and

at least one means for determining when said output signal crosses either of a high threshold value and a low threshold value.

34. The power meter of claim 33 wherein said at least one means for determining when said output signal crosses either of the high threshold value and the low threshold value includes a means for adjusting the response speed of said at least one determining means such that said at least one determining means provides an indication only when said total power voltage remains beyond either of the high threshold value and the low threshold value for a selected period of time.