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phasr loss not detected

phasr loss not detected

phasr loss not detected

(OP)
Ona recent call to check out a band saw. I checked the wire nuts in the 1900 box and found only sinle phase 220 v .With a store full of customers and numerous computers controlers etc,I used the Blow -Breaker test to isolate the specific breaker. Having notified onlookers that I was about to make a spark. Flash - PoP and retreated to the breaker pannel room. A glance at the panel and I knew which 3 phse Sqare D to reset . As my hand reached up- suddenly - all the lights in the neighborhood went dead NO POWER FROM THE MAINS.
I then find out that LIPA has been working for 3 hours. They had moved from one xformer pole to the next apparently unable to get a grip on the problem. After a 10 minute reset lipa reenergized and everything became A-OK .

QUESTION.Is it possible that the 3rd phase for a node was being auto generated (from running 3 phse motors) could my purposfull triping of a 30 amp breaker finally trigger the "Missing Phase Detector"Did the line team realize this "Auto-Generation"
Scenario.Was LIPA "missing phase detector" defective ?

RE: phasr loss not detected

A 3 phase induction motor may continue to work in 2 phases –until it will burnt out. Usually the overload protection will act fast and trip the breaker before. However, it seems sometime if the motor is slight loaded the overload protection could not "sense" the overload and not to trip the motor. See:
http://www.pge.com/includes/docs/pdfs/mybusiness/c...

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