Arc Flash & Electrical Safety News
Blog Author Steve Hudgik
Monday, July 09, 2012
Patent Granted For Low Voltage Arc Flash ProtectionThe patebt summary states:
"A method and apparatus is disclosed for providing protection against arc flash during maintenance on a low voltage power circuit including a circuit breaker having a specified trip function for responding to a fault is provided. The specified trip function is overridden with a maintenance trip function that results in reduced arc energy in the fault during a trip over arc energy during a trip with the specified trip function. The specified trip function is restored following maintenance."
What appears to have been patented is a method for reducing arc flash risk by using a four-way circuit breaker. In addition to on and off positions, the circuit breaker has two maintenance positions in which a "first level of arc flash energy" or a "second level of arc flash energy" will cause the circuit breaker to trip. Here is the description from the patent:
"The circuit breaker of claim 16, wherein the maintenance trip function comprises a first maintenance trip function that results in a first level of arc energy in the fault during a trip that is less than the arc energy resulting from a trip with the specified trip function, and a second maintenance trip function that results in a second level of arc energy in the fault that is more than the first level of arc energy but less than the arc energy resulting from the specified trip function, and wherein the maintenance switch has a first maintenance position for selecting the first maintenance trip function and a second maintenance position for selecting the second maintenance trip function."
Labels: Preventing Arc Flash Accidents
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