# Motor Failures, Questions on ICM450 phase monitor



## Galt (Sep 11, 2013)

What exactly is happening to these motors? Did you take them apart can you take pictures?


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## MotoGP1199 (Aug 11, 2014)

I only saw one motor, it was completely overheated, black out the sides of the vents, discolored paint on top rear of motor housing, windings were over heated. No signs of overheating on wires or any connections, overload relay was not tripped but one fuse was. They said on the two previous motors they saw melted metal balls on the floor below the motor openings(this one did not have that). Connections in pecker head looked great, and all connections back to the breaker are tight. I could only find one pic, not sure where the others are. The only spot on the wires that looked bad was one small spot on one wire where the insulation melted flat where it was touching the motor housing. But the wires were not exposed, insulation still there just flat. The motor rating plate states it does not have a thermal overload.


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## MotoGP1199 (Aug 11, 2014)

I'm changing out the overload relay just to be cautious. It was actually set below the SFA rating on the motor


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## Cow (Jan 16, 2008)

What does the motor run?

How often is it started and stopped?

What is the motor nameplate current and what does it run at under full load?

What is the motor service factor?


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## MotoGP1199 (Aug 11, 2014)

Cow said:


> What does the motor run?
> 
> How often is it started and stopped?
> 
> ...


Commercial pool circulation pump(small). End suction.

FLA - 12.4amps at 230 VAC
SF - 1.15
Duty - CONT
5HP

It runs 24 hours a day, They shut it off about once a week. They claim the pump never looses prime and was running at about 12 amps last time it was checked. Facility is 3 years old. Pump internals look like new. No additional bearings except whats in the motor.


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## frenchelectrican (Mar 15, 2007)

MotoGP1199 said:


> I only saw one motor, it was completely overheated, black out the sides of the vents, discolored paint on top rear of motor housing, windings were over heated. No signs of overheating on wires or any connections, overload relay was not tripped but one fuse was. They said on the two previous motors they saw melted metal balls on the floor below the motor openings(this one did not have that). Connections in pecker head looked great, and all connections back to the breaker are tight. I could only find one pic, not sure where the others are. The only spot on the wires that looked bad was one small spot on one wire where the insulation melted flat where it was touching the motor housing. But the wires were not exposed, insulation still there just flat. The motor rating plate states it does not have a thermal overload.


Did you any chance you took one end of motor housing off to see the winding to tell you the clue of why did the motor failed ?

If you ampclamp the motor to read the current you should be at or under the nameplate rating.

The only time it will go over the reading on cenifuge pumps if the discharge or suction is running unthrottled or low head set up. 

Almost all Three phase motor do not useally come with thermal overload inside the motor at all so you do need extreal overload heater/contractor protection. 

Most smaller three phase motor typically wired in Wye format so if serious unbalanced voltage it will do some funky action inside the motor. ( on serious unbalanced voltage the motor will make slightly muted knocking noise )


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## MotoGP1199 (Aug 11, 2014)

frenchelectrican said:


> Did you any chance you took one end of motor housing off to see the winding to tell you the clue of why did the motor failed ?
> 
> If you ampclamp the motor to read the current you should be at or under the nameplate rating.
> 
> ...


I have not opened it up yet. I did not try to start this motor since the shaft is really hard to turn with a wrench. Supposedly the motor is 1 month old. Staff swears it was not cavitating. About 50% of my jobs are all commercial swimming pools so I am familiar with this setup/pump. I will be checking for proper head pressure when I get the new motor hooked up. And make sure the current is below the rating plate.

Thanks for the tip on the muted knocking noise, I will look for that. At this point the customer is scared to put a new motor without some type of additional motor protection. I'll see if I can get some pics tomorrow of the motor apart.


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## micromind (Aug 11, 2007)

Long shot here but if one of the T leads in a motor operating at 230 volts becomes disconnected, the end result will be exactly as described. 

The reason is because the coils are in parallel and if one is not connected, the other one will have way more current than it can handle. 

What type of O/Ls? This sounds dumb but will an O/L trip actually cause the starter to drop out? 

O/Ls are to be sized based on the FLA, not SFA. 

Is the motor in a dry location with no water splashing on it? How about chemicals getting inside it? Even chemical vapors?


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## frenchelectrican (Mar 15, 2007)

MotoGP1199 said:


> I have not opened it up yet. I did not try to start this motor since the shaft is really hard to turn with a wrench. Supposedly the motor is 1 month old. Staff swears it was not cavitating. About 50% of my jobs are all commercial swimming pools so I am familiar with this setup/pump. I will be checking for proper head pressure when I get the new motor hooked up. And make sure the current is below the rating plate.
> 
> Thanks for the tip on the muted knocking noise, I will look for that. At this point the customer is scared to put a new motor without some type of additional motor protection. I'll see if I can get some pics tomorrow of the motor apart.


If that motor is pretty new like what you saying .,, then something is causing the issue with motor or bearing. 

It should not turn that tight at all.

Did that pump did have a motor contractor ( relay or switch if you dont get the word correct ) ? 

If so look at the overload heater or electronic overload setting to make sure it should be about same as motor nameplate. ( any variations I will explain more later ) 

5 HP is common size and you can get new overload heater or sensors depending on how the heater or overload is set up.

The other thing in motor peckerhead ( junction box ) try not to use the wirenuts much as possible I use ring termail and a small nut and bolt to lock it good because the motor viberation can cause the issue which some case the wirenuts come loose inside the peckerhead or use small split bolt in there. yes I am aware it will take more time but if done right those connection could not come apart at all.


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## JRaef (Mar 23, 2009)

One thing I would suspect is a voltage imbalance, especially because you are on a 240V Delta 4 wire service. This type of service is supposed to be for users with PRIMARILY 230V three phase loads and a SMALL amount of single phase 120V, as in 5% or less of the total. But although it might have been that way when first installed, the tenants change and nobody revisits the load. Now you have someone in there with a commercial pool, which is likely a gym or therapy center, and the load profile is now the opposite, MOSTLY 120V loads with just a few 3 phase motors. That means the line voltage goes severely unbalanced most of the time, not just occasionally. 

When a 3 phase motor gets unbalanced voltage, negative sequence currents are created in the windings and rotor. That then causes negative torque, so your motor begins to fight itself. So even though your total current flowing through the OL relay is lower than the FLA, more of that current is turning into HEAT rather than doing useful work and your windings can burn up without ever tripping the OL relay. 

So that’s what a phase monitor will help you with. But understand that it will protect the motor by shutting it down! That may trigger some angry phone calls as well. The real solution may be to change out the service and distribution. That will not be a popular idea either


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## Helmut (May 7, 2014)

I'd be looking at whether that motor is correct for the application?

I'd don't ever think I've seen an open frame motor in a pool pump application, due to the contaminants in the air.

Probably wrong, but just my 2 cents.


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## sparkiez (Aug 1, 2015)

Helmut said:


> I'd be looking at whether that motor is correct for the application?
> 
> I'd don't ever think I've seen an open frame motor in a pool pump application, due to the contaminants in the air.
> 
> Probably wrong, but just my 2 cents.


A couple people have brought this up. When I saw the picture, and that it was a pumping application, I had the same thought. Any caustic chemicals used? Is the pump moving chlorinated water? 

Non-rated motors are cheaper.

That being said, the other thing I noticed at first glance was the huge voltage difference with B-C. I wouldn't want to have that much difference between phases.

Given the fact you are investigating at the moment, those two things seem likely culprits. :vs_cool:


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## oliquir (Jan 13, 2011)

Helmut said:


> I'd be looking at whether that motor is correct for the application?
> 
> I'd don't ever think I've seen an open frame motor in a pool pump application, due to the contaminants in the air.
> 
> Probably wrong, but just my 2 cents.


search pool pump images and you'll see that a lot are open frame motors, my old one was an open frame motor.


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## oliquir (Jan 13, 2011)

MotoGP1199 said:


> Commercial pool circulation pump(small). End suction.
> 
> FLA - 12.4amps at 230 VAC
> SF - 1.15
> ...


did you check that the overload actually open the contactor? (ive seen a lot of diy install that did not used the contact on the overload and motor were burning and blowing fuses)


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