Motor trouble

Will52100

Will52100

Joined
Dec 4, 2001
Messages
3,824
:mad: For some reason I'm have trouble with electric motors. First I've been having trouble with the one on my power hammer. I've been through four motors so far, the first three vibrations broke the base off, welded up the base on the last one and maybe got the motor isolated from vibration. Then it starts tripping the breakers, got a new motor and soon as it gets warm it trips the breaker. These are one horse motors and should be plenty to pull a 50# junk yard hammer. Heck I ran a 3/4 horse for over a year before the base broke off and it never triped a breaker. It's on a dedicated 20 amp breaker.

Now my Coote is tripping a differant breaker when I get to hogging steel with it and it heats up. It's on a 15 amp breaker. Didn't used to do this, only started recently. Changed out the breaker and same thing.

Some days it doesn't pay to get out of bed! :barf:

Any idea's? :confused:
 
The circuit breakers are likely to be rated at 25 C, the proverbial "room temperature". With higher ambient temperatures, they may trip at a lower current than the rating. Of course, this would tend to be worse in the summer. Some breakers have compensation for the ambient temperature or at least less sensitivity to the ambient temperature. The detailed datasheet for the breaker(s) would include such information. Let me know if you need help finding such info.

If you have a clamp on type ammeter, you can measure your actual motor current under different conditions to see how much margin you have. Is the motor on your Coote motor running from 110V or 220V? I would have to do the math but I think that you can only ever get about 2 hp from a 110V, 15A circuit. The (in)efficiency of the motor will reduce that to something like 1 1/2 hp, at the shaft, for a single-phase motor.

Phil
 
Thanks Guys, I don't have an amp meter, but I think I know where I can borrow one from.

The motors I've got are farm duty Leeson's. May have to find anouther source of motors. Al I've got in the shop is single phase 120v.
 
Will,Check the brushes.....The heat we have here along the extra humidity lately may be causing the problem,I have had to put a fan or two blowing across the motors when I work in the summer time here.If the Breakers may be getting old also,if they break very often they start getting weak,I have had to replace some due to this myself.
Just some ideas,
Bruce

PS.You are going to have to come visit sometime.. :cool:
 
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