Device for preventive detection of faults with recognition of the type of load
First Claim
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1. A device for preventive detection of faults in a load connected to an AC supply voltage, comprising:
- a first switch connectable to an AC supply voltage;
a control circuit connectable to the same AC supply voltage comprising;
load detection means,fault detection means,voltage measuring means,load current measuring means, andtest means;
said test means for temporarily connecting said first switch to the same AC supply voltage for a half-cycle of AC voltage during a first test phase so that said voltage measuring means measures an output voltage of said first switch, and said load current measuring means measures a current of a load; and
said load detection means comprising impedance calculating means to calculate an impedance of the load based on a value of voltage from said voltage measuring means and a value of current from said load current measuring means, and comparing means for comparing the calculated impedance of the load with a plurality of predetermined impedance curves that represent a plurality of load types so that said load detection means identifies the load.
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Abstract
The device comprises an electronic switch able to temporarily connect a load to an AC power supply system so as to apply the power system voltage to the load during a test phase corresponding to a half-wave of the power system voltage. A control circuit of the electronic switch measures the output current and voltage of the device and calculates the load impedance. It compares the variation of the load impedance during the test phase to curves representative of different types of load. The device performs preventive overload detection by estimating the rated power of the load according to the type of load detected.
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13 Claims
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1. A device for preventive detection of faults in a load connected to an AC supply voltage, comprising:
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a first switch connectable to an AC supply voltage; a control circuit connectable to the same AC supply voltage comprising; load detection means, fault detection means, voltage measuring means, load current measuring means, and test means; said test means for temporarily connecting said first switch to the same AC supply voltage for a half-cycle of AC voltage during a first test phase so that said voltage measuring means measures an output voltage of said first switch, and said load current measuring means measures a current of a load; and said load detection means comprising impedance calculating means to calculate an impedance of the load based on a value of voltage from said voltage measuring means and a value of current from said load current measuring means, and comparing means for comparing the calculated impedance of the load with a plurality of predetermined impedance curves that represent a plurality of load types so that said load detection means identifies the load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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