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Joined: Oct 2002
Posts: 1
R
Junior Member
My coworker says it is OK to force a motor starter contactor by hand when troubleshooting or bumping for motor rotation. He says he ohms to ground with Fluke then uses handtool to depress contactor. I say he could loose a hand this way. I would rather troubleshoot the control circuit as to why I can't control remotely. Please let us know your opinions and experiences.

Arc Flash PPE Clothing, LOTO & Insulated Tools
Joined: Apr 2001
Posts: 507
G
Member
I do it all the time with small motors, less than 20 hp. I can't see a senario where I could potentially "loose a hand".

The biggest danger is to the equipment. If the contactor is not fully closed arcing can quickly damage the starter.

GJ

Joined: Mar 2001
Posts: 2,056
R
Member
We have entered a new age with regard to electrical safety. Many old practices are no longer considered acceptable. The dangers of arc-flash & blast are coming to the forefront with electrocution.
The practice you describe would not be accepted in a corprate environment where there was a formal electrical safety program.
I imagine the unions would frown upon it as well.

Joined: Apr 2002
Posts: 2,527
B
Moderator
Don't forget that plain-vanilla 3-wire control will "latch." If this happens and an upstream disconnet has to be opened, motor regeneration will ususally cause sluggish dropout of contactor.




[This message has been edited by Bjarney (edited 10-26-2002).]


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