Non-load driven fault monitor for electrical circuits
View Patent ↗A fault monitor for the load portion of an electrical circuit may be connected to an existing circuit by a single connection, and may detect flaws within the load portion of the circuit through the detection of changes in voltage through a resistor, caused by changes in current flow due to changing resistance within the load portion of the circuit.
1. A method of testing for faults in an electrical circuit, the circuit having a load, the method comprising the steps of:
providing a fault monitor, having:
a power supply connected in series with a resistor;
a connection for connecting to the circuit with the load in parallel with the resistor;
a voltage sensor connectcd in series with the resistor; and
switching means for opening and closing the connection between the power supply and the resistor and load;
providing a test switching means connected in series with the resistor and in parallel with the current sensor, in sequence after the first transistor;
closing the test switching means;
determining whether voltage is sensed by the voltage sensor, thereby determining whether current is flowing through the load;
connecting the fault monitor to the circuit with the load in parallel with the resistor;
passing a current through the circuit and fault monitor; and
detecting the resulting voltage at the voltage sensor, thereby determining whether the total resistance provided by the load indicates a failure within the load and also determining a number of elements having faults within the load based on the difference between the resulting voltage and an expected voltage.
2. The method according to claim 1 , wherein the steps of closing the test switching means and determining whether voltage is sensed by the voltage sensor are performed before passing a current through the circuit and fault monitor, and detecting the resulting current at the current sensor.
3. The method according to claim 1 , wherein the steps of closing the test switching means and determining whether voltage is sensed by the voltage sensor are performed after passing a current through the circuit and fault monitor, and detecting the resulting voltage at the voltage sensor.