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US 4,630,218 AGranted
Current measuring apparatus
AssigneeCooper Industries, Inc.
InventorJames R. Hurley
Life of this patent
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AssigneeCooper Industries, Inc.
InventorJames R. Hurley
Estimating the term…
A current measuring apparatus utilizes a known fundamental frequency, e.g., 60 Hz, for measuring current and includes a sensing and measurement pulse generation circuit including a current transformer for developing a low power signal directly related to the line current in a powerline, and a diode bridge with a first Zener diode for sensing when the developed current related signal exceeds a first predetermined positive threshold value and a second Zener diode for sensing when the developed current related signal falls below a second predetermined negative threshold value. Across the bridge is an LED for generating a first measurement signal having a duration related to the time when the developed signal exceeds the positive threshold value and second measurement signal during the time when the current related signal falls below the negative threshold value. The apparatus further includes processing circuitry and optical fibers for transmitting the measurement signals to the processing circuitry which is capable of processing the measurement signals durations (t.sub.1 or t.sub.2) to determine parameters of the developed current related signal thereby to determine the current flowing in the power line.
A method for measuring alternating current in a power line having a known fundamental frequency including the steps of:
Apparatus for measuring alternating current on a power line having a known fundamental frequency, including means for developing a low power signal directly related to the line current on said power line, first means for sensing when said low power signal exceeds a first predetermined positive threshold value, second means for sensing when said low power signal falls below a second predetermined negative threshold value, means for generating a first measurement signal having a duration related to the time when said low power signal exceeds said positive threshold value, means for generating a second measurement signal having a duration related to the time when said low power signal falls below said negative threshold value, processing circuitry, and means for transmitting said measurement signals to said processing circuitry, said processing circuitry processing the duration of said measurement signals to determine parameters of said low power signal thereby to determine the current flowing in said power line.
Dependencies are inferred from the claim text.