# The Importance of Proper Motor Overloads



## Big John (May 23, 2010)

This 2HP motor came into our shop for repair, and when they yanked the end-bell, this is what they found.



















That's the remains of a cast aluminum rotor. My expert opinion is I think it got a little warm. :laughing:


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## BBQ (Nov 16, 2010)

That must have stunk the place up.


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## Wirenuting (Sep 12, 2010)

A little grease and its good to go. 

Here its a loosing battle to have out maintenance, pump and service electricians change the o/l's when changing motors. 
The answer is always the same, "It worked before" & "Its suppose to run at the service factor, that's why it's labeled".


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## macmikeman (Jan 23, 2007)

FWIW, I bet it went single phase before all that happened.


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## retiredsparktech (Mar 8, 2011)

Big John said:


> This 2HP motor came into our shop for repair, and when they yanked the end-bell, this is what they found.
> 
> 
> 
> ...


 The same thing happened in an I-R screw compressor. The 60 HP must've got hot that the rotor melted in the same way. The compressor and the motor bearings didn't seize and the overloads were correct. A special OEM motor, made for IR, by Reliance. The new motor was made by Weg.


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## Big John (May 23, 2010)

I don't know enough about it to say if it's possible for an intra-rotor failure to cause that kind of heat without causing overcurrent in the stator? I'll run it by our motor gurus and see if they have any theories.


BBQ said:


> That must have stunk the place up.


 I handled the hell out of it right before lunch, and now despite washing my hands, I am eating the stinkiest sandwich ever.


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## wildleg (Apr 12, 2009)

just put more jalapenos on it and it'll all be good


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## oliquir (Jan 13, 2011)

unless it is a special motor, how would repair a tiny 2 hp motor? jsut the time for changing parts will be expensive as a new motor


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## lefleuron (May 22, 2010)

oliquir said:


> unless it is a special motor, how would repair a tiny 2 hp motor? jsut the time for changing parts will be expensive as a new motor


 No.

If a motors windings are OK, but it draws high amps the bearings are bad. Probably dry.

30 bucks in new bearings and about 15 minutes in time and you have a motor that is good to go.

That is of course unless the endbells are wallowed, then its junk.

Even at a high rate of pay, that is way cheaper then a new motor. Especially if its some type of odd frame, or god forbid of German manufacture.

That 2 HP motor could run $4000.00 bucks and be 5 weeks out.


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## Big John (May 23, 2010)

oliquir said:


> unless it is a special motor, how would repair a tiny 2 hp motor? jsut the time for changing parts will be expensive as a new motor


 That's a big "it depends." A skilled guy quickly putting new bearings in a small motor can still be economical, even if it's an off-the-shelf variety.

I agree that rewinding small off-the-shelf motors doesn't make sense, and it's easy for a repairs to quickly over-run the cost of a new motor.

But this is some special OEM motor and it will be completely rebuilt and rewound, and it's cost-effective because getting this particular motor new would be thousands of dollars.


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## Big John (May 23, 2010)

wildleg said:


> just put more jalapenos on it and it'll all be good


 Funny you say that, I had a vegi sandwich with jalapeno bread, pepperjack cheese and extra jalapenos on it. 

I figure if I gotta eat lame-ass healthy vegetables, I'm gonna make it as intense as possible.


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## ponyboy (Nov 18, 2012)

Big John said:


> ...a vegi sandwich.


A what now???


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## Cow (Jan 16, 2008)

ponyboy said:


> A what now???


I agree?!?!



Big John said:


> Funny you say that, I had a vegi sandwich with jalapeno bread, pepperjack cheese and extra jalapenos on it.
> 
> I figure if I gotta eat lame-ass healthy vegetables, I'm gonna make it as intense as possible.


I hope you're only eating a veggie sandwich today because you ran out of lunchmeat....


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## Awg-Dawg (Jan 23, 2007)

Big John said:


> I had a vegi sandwich


 
Are you poor?


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## lefleuron (May 22, 2010)

Awg-Dawg said:


> Are you poor?


 I dont know about John, but I sure would not consider myself poor,

and I eat vegetable sandwiches all the time.

They are good, and good for you.

I like them on french bread, made with fresh spinach, green olives, tomato, and a lot of banana peppers, and olive oil.

Your colon will appreciate the break.


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## BBQ (Nov 16, 2010)

lefleuron said:


> I dont know about John, but I sure would not consider myself poor,
> 
> and I eat vegetable sandwiches all the time.
> 
> ...


Pfftt, it is not a sandwich if there is no meat in it.


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## ponyboy (Nov 18, 2012)

I love animals


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## micromind (Aug 11, 2007)

I would be willing to bet that the windings in the rotor began shorting out, leading to heat concentrated in the rotor, not so much the stator. 

Notice how the stator is burned in only a few places, not the entire winding. 

Aluminum melts at about 1200º, there's no way the stator got hot enough to melt the rotor. 

BTW, that looks like a 2 pole design; somewhere around 3450 RPM.


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## erics37 (May 7, 2009)

Looks like scorched jizz.


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## Big John (May 23, 2010)

ponyboy said:


> A what now???





Cow said:


> ...I hope you're only eating a veggie sandwich today because you ran out of lunchmeat....





Awg-Dawg said:


> Are you poor?





BBQ said:


> Pfftt, it is not a sandwich if there is no meat in it.





ponyboy said:


> I love animals


:lol: Focus, guys!


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## ponyboy (Nov 18, 2012)

Big John said:


> :lol: Focus, guys!


My bad


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## JRaef (Mar 23, 2009)

erics37 said:


> Looks like scorched jizz.


Wait, what???
How the heck would you know?

Oh crap, never mind, I don't want to know...


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## retiredsparktech (Mar 8, 2011)

micromind said:


> I would be willing to bet that the windings in the rotor began shorting out, leading to heat concentrated in the rotor, not so much the stator.
> 
> Notice how the stator is burned in only a few places, not the entire winding.
> 
> ...


 I worked at a firm, that made high quality, OEM motors.
It was definitely a fault in the injection cast, squirrel cage rotor. One of the bars, might've been a high resistance bar, due to a casting fault. There was many variables in the casting operation.
I was involved in engineering testing and I witnessed rotors, failing in this manner.


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## sparkywannabee (Jan 29, 2013)

lefleuron said:


> No.
> 
> If a motors windings are OK, but it draws high amps the bearings are bad. Probably dry.
> 
> ...


It's wallered, not wallowed.


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## erics37 (May 7, 2009)

JRaef said:


> Wait, what???
> How the heck would you know?
> 
> Oh crap, never mind, I don't want to know...


When I was a kid I had a science kit thing and it had a (pretty decent actually) microscope in it. I remembered the sex ed videos from school and wondered if sperm really swam around like that.

Yep. They do.


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## JRaef (Mar 23, 2009)

erics37 said:


> When I was a kid I had a science kit thing and it had a (pretty decent actually) microscope in it. I remembered the sex ed videos from school and wondered if sperm really swam around like that.
> 
> Yep. They do.


I said I didnt want to know.... :glare:

Lol...


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## bkmichael65 (Mar 25, 2013)

erics37 said:


> When I was a kid I had a science kit thing and it had a (pretty decent actually) microscope in it. I remembered the sex ed videos from school and wondered if sperm really swam around like that.
> 
> Yep. They do.


I wonder how many hours your family had to wait for the bathroom while you were locked in there doing your "science projects"?


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## Big John (May 23, 2010)

bkmichael65 said:


> I wonder how many hours your family had to wait for the bathroom while you were locked in there doing your "science projects"?


 They probably figured Eric was gonna grow up to win the Nobel Prize. :laughing:


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## Norcal (Mar 22, 2007)

ponyboy said:


> I love animals


PETA = People Eating Tasty Animals.


All jokes aside, if vegetarian food is good (and it can be) I can go without meat, but no way in hell would I be a vegan. When was in Germany in Sept. 2011 ate nothing but vegetarian food but then my aunt is a good cook.


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