System and method for detecting arcing in dynamoelectric machines
First Claim
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1. In a system for detecting an arcing fault in a dynamoelectric machine having a neutral grounding lead:
- a radio frequency voltage coupler coupled to the neutral lead, a radio frequency monitor coupled to the voltage coupler for monitoring radio frequency voltage in the neutral lead, and an alarm circuit coupled to the radio frequency monitor for providing a warning signal in response to a change in the radio frequency voltage and a shutdown signal in response to a radio frequency voltage greater than a predetermined level.
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Abstract
System and method for detecting arcing faults in a dynamoelectric machine by monitoring the neutral lead of the machine for a radio frequency voltage produced by arcing, providing a warning signal in response to a change in the radio frequency voltage, and providing a shutdown signal in response to a radio frequency voltage greater than a predetermined level. An RF voltage coupler is capacitively coupled ot the neutrla lead, and a radio frequency monitor connected to the voltage coupler detects peaks in the RF voltage.
72 Citations
22 Claims
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1. In a system for detecting an arcing fault in a dynamoelectric machine having a neutral grounding lead:
- a radio frequency voltage coupler coupled to the neutral lead, a radio frequency monitor coupled to the voltage coupler for monitoring radio frequency voltage in the neutral lead, and an alarm circuit coupled to the radio frequency monitor for providing a warning signal in response to a change in the radio frequency voltage and a shutdown signal in response to a radio frequency voltage greater than a predetermined level.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a system for detecting an arcing fault in a dynamoelectric machine having a neutral grounding lead:
- a capacitive voltage coupler coupled to the neutral lead responsive to radio frequency voltages produced in the neutral lead by arcing in the machine, an amplifier having a high input impedance connected to the voltage coupler, a bandpass filter for selectively passing radio frequency signals within a predetermined frequency range from the amplifier, a storage capacitor, means responsive to the level of the signal from the bandpass filter and to the charge on the storage capacitor for applying pulses to the storage capacitor when the level of the signal from the filter is less than the charge on the capacitor, and an alarm circuit coupled to the storage capacitor for providing a warning signal in response to a change in the charge on the capacitor and a shutdown signal in response to a charge on the capacitor greater than a predetermined level.
- View Dependent Claims (12, 13, 14)
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15. In a method of detecting an arcing fault in a dynamoelectric machine having a neutral grounding lead, the steps of:
- monitoring the neutral lead for a radio frequency voltage produced by arcing in the machine, providing a warning signal in response to a change in the radio frequency voltage, and providing a shutdown signal in response to a radio frequency voltage greater than a predetermined level.
- View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
Specification