# Shaker motor wants to break free.



## Wirenuting

Bad bearing?


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## MDShunk

I guess doing a vibration analysis is out? :vs_laugh:

In general, the shaker motor bolts shouldn't break off if the thing it's shaking is sufficiently free to shake. Air bag blown? Springs broken/missing/replaced with bolts instead?


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## MDShunk

Any chance you can put this on a drive and slow it down a little bit? (assuming there's excess unnecessary capacity).


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## emtnut

If you think it's a mounting issue (hairline crack or whatever) , try a Nord-Lock washer.

If it's coming loose and the screen blocks up, could explain the OL.


Or you could just install VSDs on all 3 :vs_laugh:


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## MDShunk

It's really hard to keep a shaker motor bolted back down after it's come aloose a few times. The holes wallow out in the motor foot and the mounting frame and it lets side to side motion happen even if the bolts are tight. Drilling them out for a tight fit for the next standard bolt size up, or lathe turning custom bolts may be a good option. Dowel pinning the feet may be another decent option.


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## cad99

Drive would be nice but the company drive budget is maxed with bringing more things up on delta v.I have taken the counter weight adjust from 100% down to 80% then yesterday 75%.Springs are visually ok motor is five months old and greased monthly.

The capacity of the system is maxed when one goes down causing flooding and beet parts to run down a flight of steps and flood the main floor of this building. In a fight if a electrical or mechanical problem. Have three rebuilds of this motor but would need a crane to get to close to its home. I appreciate the help hopefully in a few weeks can schedule shut down and replace/inspect everything. 


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## JRaef

Weld that puppy! For the amount of time you are wasting by constantly replacing bolts etc., the fact that you'd have to grind welds off to remove it for maintenance may be irrelevant.

But I agree on the hole issue. I did a lot of rock crusher shaker motors, 25-40HP, and they take a lot of abuse. But once those holes go oblong, it's all down hill from there. Drilling them out to the next size up is a temporary fix because you reduce the material and the feet crack off, then the entire frame is toast. I once had an ace welder who machined out the holes, then welded back in a hardened insert sleeve for the bolt to go through. Still wore out, but lasted longer than the original.


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## QMED

How about welding some jacking bolts on? That way you can still remove the motor when necessary. Take some thick stock and thread holes for the jacking bolts, weld them on either side of the motor and crank the hell out of them. Assuming you have enough downward clamping force from the mounting bolts.


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## MikeFL

I'd be suspect of the bolts you're putting in. One way to find out is to swap out known good bolts from a motor which does not have a problem with new bolts and put the known good bolts in the problem motor and see how they hold up.


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## splatz

I hesitate to post this because I get my info from grown men that race go carts but I hear the Nord-locks are popular, however, they aren't the end all. @paulengr has posted some links that they are not as good as they claim. 

They use safety wire too, I don't know if that would work in this application, they use it in aviation and racing to keep things from rattling loose. I am sure there's a lot less energy in the vibration but maybe it would work ... 










Along the lines of JRaef's idea about hardened inserts - I would think you could use hardened inserts and double up or even triple up the thickness of the hole, the thickness works two ways to slow down that wear into an oval - once the hole is out of round, it's just a matter of time.


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## Helmut

Nope. it's me


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## John Valdes

I had one of those shaker motors in every dept at a plant I worked at.
I don't remember but one or two times in 5 years I was ever called over on one of them.
I am trying to picture how they were mounted with little success. Its been close to 20 years since I worked there. But I do know we had little issues with them.


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## John Valdes

How about a picture of the nameplate.
How many do you have and does this happen with all of them?
Or is it just one application?


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## joebanana

Is there a machine shop at this facility? Any millwrights? Sounds more like a mechanical issue than an electrical one.
If the shaker motor is shaking, it's doing what it's designed to do. If it's falling off the equipment, maybe the equipment isn't doing it's job.


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## just the cowboy

I just had one that was breaking mounting plates, called manufacture and sent pictures. They right away knew why, mounted wrong way for vibration. This is not your problem but I would call manufacture and see what they say.


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## John Valdes

Joe. I’m certain every poster in this thread thought/knew it was mechanical. I agree 100%
However. I wanted to see the rpm


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## cad99

John Valdes said:


> How about a picture of the nameplate.
> How many do you have and does this happen with all of them?
> Or is it just one application?




Three in this area and another ten moving coal. I can grab name plates when I go back this evening just switched to night shift. 


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## cad99

100% Agree mechanical issue. Nightly precent of my job seems to be proving that a issue is mechanical or instrumentation or vise versa. 

Since this motor trips o.l.’s before it falls off and lands in to a scroll it must be a electrical seems to be the way of thinking. 


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## Wiresmith

do you have a bolt in every hole? the picture shows 4 on one side? use better bolts and the largest you can fit in the motor hole and nord-lock washers


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## John Valdes

cad99 said:


> Three in this area and another ten moving coal. I can grab name plates when I go back this evening just switched to night shift.


Is this a widespread issue or just an isolated issue?



cad99 said:


> 100% Agree mechanical issue. Nightly precent of my job seems to be proving that a issue is mechanical or instrumentation or vise versa.
> Since this motor trips o.l.’s before it falls off and lands in to a scroll it must be a electrical seems to be the way of thinking.
> 
> Once this thing starts to come loose, the offset weights are not controlled and I can see the OL and even a possible short in connections. Mechanical connections too.





Wiresmith said:


> do you have a bolt in every hole? the picture shows 4 on one side? use better bolts and the largest you can fit in the motor hole and nord-lock washers


If I remember correctly, there was a spec on the bolts and a spec on torque. The shakers were also OEM designed for the application.
In that plant I just disconnected and reconnected motors.
So, I am not exactly sure.


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## joebanana

cad99 said:


> 100% Agree mechanical issue. Nightly precent of my job seems to be proving that a issue is mechanical or instrumentation or vise versa.
> 
> Since this motor trips o.l.’s before it falls off and lands in to a scroll it must be a electrical seems to be the way of thinking.
> 
> 
> Sent from my iPhone using Tapatalk


I can totally relate. At the refinery, they always called the electricians first, to tell them which other trade to call to fix the problem. Usually instrumentation.
How do they know the OL's trip BEFORE it falls off? If that were the case, why does it still fall off?


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## cad99

joebanana said:


> I can totally relate. At the refinery, they always called the electricians first, to tell them which other trade to call to fix the problem. Usually instrumentation.
> How do they know the OL's trip BEFORE it falls off? If that were the case, why does it still fall off?




Because electrician/me gets called because it doesn’t work, always tripped overlords. Reset bang bang bang. Shut off motor crawl up ladder and see the bolts all loose and some Missing repeat every two weeks 


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## cad99

John Valdes said:


> Joe. I’m certain every poster in this thread thought/knew it was mechanical. I agree 100%
> However. I wanted to see the rpm















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## joebanana

cad99 said:


> Because electrician/me gets called because it doesn’t work, always tripped overlords. Reset bang bang bang. Shut off motor crawl up ladder and see the bolts all loose and some Missing repeat every two weeks
> 
> 
> Sent from my iPhone using Tapatalk


Is the manufacturer of the equipment still in business? Maybe they have a solution. (or recall)


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## paulengr

I'm an ex mining maintenance guy. Dealt with this a lot.
First off 2 or 4 bearing shaker? Sounds like 2 bearing. Next time buy the 4...thank me later. Or go with one that uses pancake vibrators but don't bug or throw away their crap SCR controller when it fails. PM and I'll send you my super unintended indestructible lifetime guaranteed shaker controller. Dozens installed around the world and none have burned up. FMC can eat their heart out. Trouble is mine is so cheap and simple I can't sell it.

Second have you put a shaker "scale" on it yet to check if it's too much/little? When you adjust the counterweight there are stickers or labels that you can read to tell how much it vibrates. Get it wrong and it will never stay together.

Third as others have said check around every spring, bump stop, etc. All need to be clear of any interference and all wearing evenly or...see item 2, shaker rips itself apart. Same with cracked elastomers, etc.

If it's the off screen or on screen belt driven kind, check belt drive alignment then get the Lovejoy elastomer motor mount to save your belts and motor bearings.

Do NOT try to use stock motors. You need a heavy cast motor with epoxy instead of varnished coils, heavier bearings, and oversized air gap. Vibrator motors are pretty special.

As others stated Jost effect (Google it or look at boltscience.com) is the problem. If the bolt doesn't fit tight and properly torqued with huck bolts (best I've found), lock nuts, or double nutted in the right way, no lock washers or especially helical spring washers (split washers), forget it. Throw away old hardware...new every time. Use a DTI (squirter washer) or an ultrasonic tension meter with neverseez or "security grade" Loctite, or a torque wrench if you can't do so the of those. Once a bolt gets loose it permanently stretches and wallows out the hole. That's it after that. Drill out and drill at least 1/4" past any cracks. Reweld with 6010 roots and 7018 filler. New 7018 out of can or rod oven only, toss after 40 minutes out of can/oven. Machine (not just grind) flat and inspect weld before/after. Pre and post heat welds. Then drill holes back out to size. As others stated if you don't do it right it will never be the same.

On big rock screens in 24/7 quarries most screens get 18-24 months out of side plates and replace the whole thing every 5 years on 2 bearing designs. Certain designs do suck worse than others.



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## bill39

joebanana said:


> Is there a machine shop at this facility? Any millwrights? Sounds more like a mechanical issue than an electrical one.
> If the shaker motor is shaking, it's doing what it's designed to do. If it's falling off the equipment, maybe the equipment isn't doing it's job.


100% agree with the above comment.

This sounds like another example of trying to correct a mechanical problem with an electrical fix. If it worked OK originally, then what changed?

Lubrication or alignment needed maybe?
Maybe the shaker is overweight?

MD Shunk’s idea of a drive is a good one but only if everything mechanical is checked out first.


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## JRaef

As to the OLs tripping;
Once the holes go oblong the motor will skew to one side, putting side tension on the drive belt and thus increasing the load on the motor. it's the same thing you see when a motor goes out of alignment. The OL relay is just preventing a fire at that point.


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## paulengr

PHP:




That's an FMC motor and those guys make tons of vibrators. BUT you have to be careful with them. If you oversize the vibrator, it will rip out bolts/equipment. If you don't adjust the counterweights correctly, it will rip things apart. If you don't torque the bolts properly, it will rip things apart. If you use the wrong nuts and bolts and don't use new every time, it will rip things apart. If the pins, springs, shocks, belts, elastomers, etc., are worn out, it will rip things apart. Material build up pushing on the screen either out of the hopper or from unrepaired leaks around it will rip things apart. AND it gets worse from there. FMC just makes vibrators, not screens. There are some truly bad designs out there and often sites try to tinker with the design and usually cause themselves more problems.


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## muffintop

Did you ever get a solution to this thing basically killing itself? Kinda curious reading.....


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## cad99

muffintop said:


> Did you ever get a solution to this thing basically killing itself? Kinda curious reading.....




Shutting everything down for two months after Memorial Day the whole system will be gutted and I will pull bearings,springs and get a machinist to check out all the mounting holes. 


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