Method and apparatus for monitoring electrical loads
First Claim
1. Apparatus for controlling plural electrical loads supplied with power from a single power source, the apparatus comprising:
- a. means for controlling energization of the loads to periodically isolate and energize singularly each of the loads;
b. a single current sensing means for producing a current signal representing the current delivered by the power source; and
c. means responsive to the current signal and the controlling means for detecting the value of the current signal during isolated energization of each load; and
d. means responsive to the detecting means for determining whether the value of the current signal during isolated energization of each load is abnormal for the selected load.
4 Assignments
0 Petitions
Accused Products
Abstract
Plural electrical loads supplied with power from a single source are monitored to detect defective loads. Each load is periodically individually energized and current delivered by the source is measured. Measured current for each load is compared with limit values to detect abnormal values. To overcome consequences of supply voltage fluctuations, supply voltage is also measured and admittance of each load is determined from measured current and measured voltage. The admittance value thus determined for each load is compared with limit values to detect abnormal values. Load monitoring of loads energized according to a control algorithm proceeds by periodic momentary suspension of energization according to the control algorithm and energization of selected individual loads.
27 Citations
14 Claims
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1. Apparatus for controlling plural electrical loads supplied with power from a single power source, the apparatus comprising:
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a. means for controlling energization of the loads to periodically isolate and energize singularly each of the loads; b. a single current sensing means for producing a current signal representing the current delivered by the power source; and c. means responsive to the current signal and the controlling means for detecting the value of the current signal during isolated energization of each load; and d. means responsive to the detecting means for determining whether the value of the current signal during isolated energization of each load is abnormal for the selected load. - View Dependent Claims (2, 3, 4)
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5. Method to detect a fault in any of plural electrical loads supplied with power from a single source, the method comprising the steps of:
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a. controlling energization of the loads to periodically isolate and energize singularly each of the loads; b. producing a measured current signal representing actual current delivered from the power source; c. determining a value of admittance of each load as the ratio of the actual current delivered during isolated energization of each load to the voltage of the power source; and d. detecting an abnormal value of admittance, a load fault being indicated by an abnormal value of admittance. - View Dependent Claims (6, 7)
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8. Method to detect abnormal admittance of any of plural electrical loads supplied with power form a single power source, the power being supplied to the loads in accordance with a control algorithm, the method comprising the steps of:
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a. periodically suspending energization of loads according to the control algorithm to isolate and energize singularly each of the loads; b. producing a measured current signal representing actual current delivered from the power source; c. determining a value of admittance of each load as the ratio of the actual current delivered during isolated energization of each load to the voltage of the power source; and d. detecting an abnormal value of admittance. - View Dependent Claims (9)
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10. Apparatus to detect abnormal admittance of any of plural electrical loads supplied with power from a single power source, the apparatus comprising:
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a. means for producing a measured current signal representing actual current delivered from the power source; b. means for producing a measured voltage signal representing actual voltage of the power source; c. means for controlling energization of the loads to periodically isolate and energize singularly each of the loads; d. means responsive to the measured voltage signal and the measured current signal for producing in response to isolated energization of each load an admittance signal representing the admittance of each load; and e. means for detecting an abnormal value of admittance of the selected load. - View Dependent Claims (11, 12)
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13. Apparatus for controlling plural electrical heaters supplied with power from a single power source, the apparatus comprising:
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a. means for controlling energization of the heaters according to a temperature control algorithm for effecting temperature control; b. means for periodically suspending energization of the heaters according to the temperature control algorithm and for isolating and energizing singularly each of the heaters; c. single current sensing means for producing a current signal representing the current delivered form the power source; and d. means responsive to the current signal for producing a fault indicating signal in response to detection of an abnormal value of the current signal during isolated energization of a load. - View Dependent Claims (14)
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Specification