Current switch with automatic calibration
First Claim
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1. A method of monitoring a current in a power cable, said method comprising the steps of:
- (a) storing a default activation current in a memory before measuring a current in said power cable;
(b) measuring a current in said power cable;
(c) if an activation current stored in said memory is said default activation current, replacing said default activation current with a stored activation current determined from a measured current in said power cable; and
(d) initiating and, alternatively, disabling an alarm if a magnitude of said power cable current varies in a predetermined manner from said stored activation current.
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Abstract
A current switch is automatically calibrated when a flow of electric current is initiated in a power cable.
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Citations
17 Claims
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1. A method of monitoring a current in a power cable, said method comprising the steps of:
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(a) storing a default activation current in a memory before measuring a current in said power cable; (b) measuring a current in said power cable; (c) if an activation current stored in said memory is said default activation current, replacing said default activation current with a stored activation current determined from a measured current in said power cable; and (d) initiating and, alternatively, disabling an alarm if a magnitude of said power cable current varies in a predetermined manner from said stored activation current. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of monitoring a current in a power cable, said method comprising the steps of:
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(a) before measuring a current in said power cable, storing in a memory a default value for a plurality of activation currents, each of said activation currents correlated to a range of frequencies; (b) detecting a frequency of said current in said power cable; (c) measuring a magnitude of said power cable current; (d) selecting one of said stored activation currents, said selected activation current correlated to a range of frequencies inclusive of said frequency of said power cable current; (e) if said selected activation current has a default value, determining a new activation current from said measured magnitude of said power cable current; (f) storing said new activation current as replacement for said selected activation current; and (g) initiating and, alternatively, disabling an alarm if said power cable current varies in a predetermined manner from a stored activation current correlated to a measured frequency of said power cable current. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A current switch for monitoring an electric current in a power cable, said current switch comprising:
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(a) a current sensor producing an output signal in response to a current in a power cable, said output signal having a magnitude related to a magnitude of said power cable current and a frequency related to a frequency of said power cable current; (b) a memory communicatively connected to enable a data processing device to store a value for an activation current in said memory and read said stored value of said activation current, a default value for said activation current being stored in said memory before said power cable current is sensed; and (c) a data processing device communicatively connected to said memory and said current sensor, said data processing device including a program instruction to cause said data processing device to; (i) measure of a magnitude of said power cable current; (ii) read said stored value of said activation current; and (ii) if said stored value of said activation current is said default value, replace said stored value of said activation current with a new activation current determined from said measured magnitude of said power cable current. - View Dependent Claims (15)
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16. A current switch for monitoring an electric current in a power cable, said current switch comprising:
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(a) a current sensor producing an output signal in response to a current in a power cable, said output signal having a magnitude related to a magnitude of said power cable current and a frequency related to a frequency of said power cable current; (b) a memory communicatively connected to enable a data processing device to store a value for each of a plurality of activation currents, each said activation current correlated to a frequency, and read said stored values of said activation currents, a default value being stored in said memory for each said activation current before said power cable current is sensed; and (c) a data processing device communicatively connected to said memory and said current sensor, said data processing device including a program instruction to cause said data processing device to; (i) measure a frequency of said power cable current, (ii) measure of a magnitude of said power cable current; (iii) read said stored value of said activation current correlated to said frequency of said power cable current; and (iv) if said stored value of said activation current is said default value, replace said stored value of said activation current correlated to said frequency of said power cable current with a new activation current determined from said measured magnitude of said current in said power cable. - View Dependent Claims (17)
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Specification