# Motor help



## Helmut (May 7, 2014)

Customer smoked a 125HP 3 phase 440V motor, so they got a replacement from another division.

Smoked motor was 3 leads,

New motor is 440V rated, not dual voltage, 6 leads

1,2,3 are tied together, feeds on 4, 5, 6.


Does it matter if 4,5,6, are tied together and you feed 1,2,3, or is it the same as 1,2,3 together and then feed 4,5,6?

Dual HP rated motor. 125Hp or 60Hp, I assuming if it's wye, it's set up for 60Hp.

Sound correct?


Just never seen putting hots on 4,5,6 alone.


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## MDShunk (Jan 7, 2007)

Feeding 4,5, and 6 and shorting 1,2,3 would be a high speed constant torque connection for a 2 speed motor. Sounds correct if your dataplate is marked with 2 different horsepowers, one being exactly half of the other. 

If you were to feed 1,2,3 I think you'd need to leave 4,5,6 capped off from each other and you'd only get low speed. 

These two speed motors always screw with my head. There's so many varieties. My guess is that if someone fed 1,2,3 and shorted 4,5,6, that might be why the motor smoked. In manufacturing, I'd also guess that at least 1 out of every 10 2-speed motors that gets newly wired is immediately smoked, based on my personal observations. Sorry to say.


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## John Valdes (May 17, 2007)

See Page 2 and save file.

http://www.goevans.com/filesSite/EHB_pgs0803.pdf


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## MDShunk (Jan 7, 2007)

John Valdes said:


> See Page 2 and save file.
> 
> http://www.goevans.com/filesSite/EHB_pgs0803.pdf


I wasn't really thinking wye-delta start because of the two horsepowers marked on the dataplate.


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## Helmut (May 7, 2014)




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## MDShunk (Jan 7, 2007)

Sure looks like two speed constant torque to me. That would be page 6 on the document John linked to.


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## MDShunk (Jan 7, 2007)

I wonder what the "S" is for on the frame size? Is this some sort of special or modified 504 frame?

edit: nevermind. I looked it up. It's normal. Somebody really got hosed if they're buying electric motors from General Dynamics. Holy crap.


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## Helmut (May 7, 2014)

Marc answered it.


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## Helmut (May 7, 2014)

MDShunk said:


> I wonder what the "S" is for on the frame size? Is this some sort of special or modified 504 frame?
> 
> edit: nevermind. I looked it up. It's normal. Somebody really got hosed if they're buying electric motors from General Dynamics. Holy crap.


I have no clue.


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## Helmut (May 7, 2014)

I guess the next question would be is the currently used starter and overloads?

I suppose I may need to adjust them, depending on how this thing gets wired for what horsepower and speed they need?


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## MDShunk (Jan 7, 2007)

Helmut said:


> I guess the next question would be is the currently used starter and overloads?
> 
> I suppose I may need to adjust them, depending on how this thing gets wired for what horsepower and speed they need?


Worth looking into, but if it's a like for like replacement, that's probably already covered. I guess we're all exactly old enough that we don't assume that, though. Is the old motor still kicking around their place so that you can see what it's rated HP, RPM, and amp draw was?


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## Helmut (May 7, 2014)

MDShunk said:


> Worth looking into, but if it's a like for like replacement, that's probably already covered. I guess we're all exactly old enough that we don't assume that, though. Is the old motor still kicking around their place so that you can see what it's rated HP, RPM, and amp draw was?


It's still there, just took cam locks off this morning, and was going to wire new replacement and then I encountered 2 dilemas. One was being a motor I've never seen before, and the other is the pecker head is 1/2" cast steel. The shop there has to bore holes in it for me. I'll head back in half an hour and post original motor nameplate.


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## MDShunk (Jan 7, 2007)

Cool. My worry there, because I've seen it before, is that the old motor was 1725 rpm at 125hp and they gave you a two-speed motor thinking you could wire it for low speed, but you'd only get 60hp with this particular motor since it's not a two-speed, constant horsepower motor.


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## Helmut (May 7, 2014)




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## Helmut (May 7, 2014)

Appears that if I leave it wired the way it came, I'm good.


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## MDShunk (Jan 7, 2007)

Close enough RPM's and same HP when you wire it high speed. 15 more amps with the new motor, so overloads need investigated. Different frame type. I guess they already know that and have determined they can mount and couple it okay?


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## Helmut (May 7, 2014)

MDShunk said:


> Close enough RPM's and same HP when you wire it high speed. 15 more amps with the new motor, so overloads need investigated. Different frame type. I guess they already know that and have determined they can mount and couple it okay?


Yeah, the 2 motors are different physical sizes. The have to build some mount extension, and I'm glad I went back. Where it gets mounted, you can't come out of the bottom of the pecker head, like the old motor. Have to come out the back side instead. Glad I caught it, before they chucked it up and bored holes for me.


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## MDShunk (Jan 7, 2007)

Helmut said:


> Appears that if I leave it wired the way it came, I'm good.


Did somebody just chop the old feed off that replacement motor when it was torn out before, so you have artifacts of how it was wired? That's kinda nice, if that's the case.


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## Helmut (May 7, 2014)

MDShunk said:


> Did somebody just chop the old feed off that replacement motor when it was torn out before, so you have artifacts of how it was wired? That's kinda nice, if that's the case.



I wish. It came in as I explained. They said the replacement works, someone ran it years ago, yet the peckerhead has no holes for conduit or cables, and it was wired as I explained.

I can only assume they ran it, with the cover off the peckerhead.


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## pudge565 (Dec 8, 2007)

Helmut said:


> I guess the next question would be is the currently used starter and overloads?
> 
> I suppose I may need to adjust them, depending on how this thing gets wired for what horsepower and speed they need?





MDShunk said:


> Worth looking into, but if it's a like for like replacement, that's probably already covered. I guess we're all exactly old enough that we don't assume that, though. Is the old motor still kicking around their place so that you can see what it's rated HP, RPM, and amp draw was?





MDShunk said:


> Cool. My worry there, because I've seen it before, is that the old motor was 1725 rpm at 125hp and they gave you a two-speed motor thinking you could wire it for low speed, but you'd only get 60hp with this particular motor since it's not a two-speed, constant horsepower motor.


Overloads should always be checked when a motor is replaced as they are sized to the motor nameplate and involves knowing service factor and temp rise. Normally, a like for like motor probably wont require adjustment as the nameplate values will be close enough to stay in the 115 or 125 percent of the nameplate value as applicable.

As far as the starter, that should be fine as they are normally sized to the horsepower.

I had a case at the plant I worked at where they had a pit pump outside in a wet well with a manhole. The plant had 2 different sized pumps, one a 5 HP and the other a 7.5 HP (they actually had 3 in rotation so you never really knew what was on the shelf at the time). Well no one ever checked the overloads when replacing the pump and any time the floor guys washed wood debris from pallets down the drains and the pump sucked it up the pump would burn up. I was working to rectify this with a new starter and electronic over load that is easier to set. Ideally, I wanted them to choose either 7.5 or 5 HP and stick with that size pump but well that didn't go over well (too expensive). I was also pricing out a Muffin Monster to put in the water stream to break down the wood debris and make this all a moot point. It never got completed as they fired me prior to completion...


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## MDShunk (Jan 7, 2007)

A lift pump normally has a "trash basket" to catch stuff like you're talking about. Strange yours didn't.


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## pudge565 (Dec 8, 2007)

MDShunk said:


> A lift pump normally has a "trash basket" to catch stuff like you're talking about. Strange yours didn't.


This company was ass backwards... Had a motor disconnect switch enclosure filling with water on wash down nights that the maintenance manager told me and my co-worker to fix. I said sure and put in a requisition for a stainless steel drain figuring I'll punch a 3/4" hole and put this in. Manager denied the request. He wanted us to find the source of the water and rectify it... The 400 PSI hot water hoses for wash down were the culprit, not sure how I was supposed to keep that water from entering all conduits and enclosures...

That place fired me on bogus charges (union wasn't much help other than providing the lawyer for my arbitration that I lost...) I was a miserable prick though, that happens when they work you 12 days on one day off. I had to work 21 or more days straight so I could plan on attending things with family and such. Worst place I ever worked.


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## emtnut (Mar 1, 2015)

Helmut said:


> Customer smoked a 125HP 3 phase 440V motor, so they got a replacement from another division.
> 
> Smoked motor was 3 leads,
> 
> ...


Dude, you really shouldn't be playing with motors :vs_whistle:


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