# Weird Lift station problem



## gpop (May 14, 2018)

I get called to a lift station that's blowing its control fuse and smoking. Few people there already including a few contractors and they can not figure out the problem. (started off as a pump problem until the control fuse blew)

So its late and spitting of rain so im hoping for a quick in and out so i power down the panel. Do a quick meg on the motors then pull the wire's and meg each float.
Everything passes so i deiced to see whats going when the panel is live. I installed a new fuse and powered up and tried pump one and nothing happened. Put a meter on one side of the coil and tried again and it has 120v. Test across the coil and its 120v. Power down and try to force the contactor and its jammed, Ohms open so the coil is probably melted. 

Try pump two and it closes in hand. Switch it to off and it stays energized. Shut the panel down to check the wiring and do not see a problem. Power back up and nothing works because the control fuse is blown. I unwire the contactor on pump one as that's got to be the problem and try again. Same results.
So im trying to figure why a control fuse would blow when the panel is powered down. so attempt number 3 i throw the pump into hand then turn the switch to off and sob still has 112v on the coil so i throw the breaker and start testing the switches etc.

I can not find the problem but the panel does smell a little smokey yet nothing tests bad. I send my trainee to grab a new contactor from down the road and carry on testing. He comes back with a cup of coffee so i take a break as im getting frustrated. He starts asking what the problem is and i explain i have a back feed and can not find it. He points out that i have always preach that when it doesn't make sense to start at the beginning and trust the meter.
Sounds better than my plan of taking a hammer to the panel so i start again. Grab the meg and test a= 550 b= 550 c= 0. Dam wish i had not taken the short cut and only megged one leg earlier. Ohmed the legs and they are all open. 
Then i get the oh f***. On the print it showed the thermal after the hoa switch and i never considered the switch as a possible back feed as there was no power source it could use. Well now i know that C is megging low that opens up a possible no matter how remote that C is shorted to the thermal switch. few tests prove that to be correct.

Everything is fine until you put the pump in hand or have a high level and it starts in auto. Now you get up to 277v going head to head with the control transformer and the fuse pops But here is the kicker, even with the control fuse popped you now have around 120 ish on the controls. I have no idea whats going on in that motor but i have found the problem. Now i just wanted to see what happens in the instance the contactor closes so i get the trainee to turn the switch to hand while i measure the voltages. 
It starts at 120 (control transformer) then spikes to 250 ish which is C phase then settles to 120 ish. 
Well this explains pump one coil melting and the back feed. So i un-wire the motor and replace the contactors. We do not have a spare pump locally so we deiced to run on one pump but now the alternating relay is being stupid so im guessing that did not like the 250 ish voltage either so i replace that then find the low level float is glitchy so we also replaced that. 

So im going with (maybe wrong but sounds good on paper)
low level float being glitchy caused pump to rapidly cycle leading to coil pack in pump to overheat and short to thermal switch wiring. This caused a back feed to the panel and fried the other pump contactor, alternating relay, etc. Pumps have been reset a few times which explains why the overloads did not take care of the problem.


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## 460 Delta (May 9, 2018)

When you say thermal, do you mean an imbedded Klixon in the motor windings? Like Westinghouse’s motor Watchman?


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## oldsparky52 (Feb 25, 2020)

gpop said:


> He starts asking what the problem is and i explain i have a back feed and can not find it. He points out that i have always preach that when it doesn't make sense to start at the beginning and trust the meter.
> Sounds better than my plan of taking a hammer to the panel so i start again.


1st, thanks for taking the time to share this story! 

2nd, I'm jealous. Your helper pays attention to you. Sounds like a keeper.


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## Navyguy (Mar 15, 2010)

Do you have a drawing or is this a standard alternator pump set-up?

Cheers
John


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## 460 Delta (May 9, 2018)

oldsparky52 said:


> 1st, thanks for taking the time to share this story!
> 
> 2nd, I'm jealous. Your helper pays attention to you. Sounds like a keeper.


Sounds like the “helper” has crossed over the line to the apprentice/trainee category.
These are the guys that management needs to recognize their worth and pay them accordingly as their skill set increases.


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## gpop (May 14, 2018)

Navyguy said:


> Do you have a drawing or is this a standard alternator pump set-up?
> 
> Cheers
> John


Basic old school set-up. 4 floats and everything at control voltage (no intrinsically safe stuff).

You have a hoa for each pump, Auto comes off the alternating relay, Hand is 120v. Then hoa common goes via the thermal switch (N/C) which is built into the motor to the contactor then digital overload to N. (aux used for the run light).


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## gpop (May 14, 2018)

460 Delta said:


> When you say thermal, do you mean an imbedded Klixon in the motor windings? Like Westinghouse’s motor Watchman?


yes. Not sure what kind or how many unless i get to open the motor. Im tempted to do that as it interesting but its a Ka-Ka station so its going to need pressure cleaning before i go that far.


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## SWDweller (Dec 9, 2020)

Does the control circuit pass through the floats?
I had a float leak and would occasionally take out the controls. 
I moved on to floats on a gfci, and a relay to separate them from the controls
I put gfci on the floats for the mechanical guys that I did not want to go to their funerals. 
Always amazed me that they would climb down the ladder and move the float by hand.,


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## gpop (May 14, 2018)

SWDweller said:


> Does the control circuit pass through the floats?
> I had a float leak and would occasionally take out the controls.
> I moved on to floats on a gfci, and a relay to separate them from the controls
> I put gfci on the floats for the mechanical guys that I did not want to go to their funerals.
> Always amazed me that they would climb down the ladder and move the float by hand.,


Most of our stations floats are hooked to intrinsically safe low voltage relays due to explosive gases this one is not as i believe its a kitchen wet well. 

As for people entering the station there's 5 pages of permits so there no risk as everything's is shut down and locked out.


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## paulengr (Oct 8, 2017)

Hate to break it to you but even after hosing it down, sewage pumps still stink bad. Until you run it through a burnout oven, forget it.

There is nothing really to a Klixxon and they are dirt cheap. Usually cement one per phase in before dipping it in varnish or epoxy before baking out. It works like a bimetallic strip.


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## gpop (May 14, 2018)

thermal is O/T 2 (24 and 25). Somehow that became shorted to C phase in the motor causing the backfeed


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## gpop (May 14, 2018)

paulengr said:


> Hate to break it to you but even after hosing it down, sewage pumps still stink bad. Until you run it through a burnout oven, forget it.
> 
> There is nothing really to a Klixxon and they are dirt cheap. Usually cement one per phase in before dipping it in varnish or epoxy before baking out. It works like a bimetallic strip.



Have you ever seen one short to a phase with out going to ground?


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## gpop (May 14, 2018)

This also confused me but its what the label says

3HP 
460V 
FLA 8.9 .......Seriously.
tested at 8.7 when pumping.


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## micromind (Aug 11, 2007)

Yeah, it doesn't make sense........8.9A @ 460V is more like 7.5HP.........


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## cmdr_suds (Jul 29, 2016)

micromind said:


> Yeah, it doesn't make sense........8.9A @ 460V is more like 7.5HP.........


Note the rpms, 2 pole motor, not 4. So the FLAs will be different than standard HP-FLAs


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## gpop (May 14, 2018)

cmdr_suds said:


> Note the rpms, 2 pole motor, not 4. So the FLAs will be different than standard HP-FLAs



HP is HP. 
higher speed lower torque verses lower speed with higher torque.


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## 460 Delta (May 9, 2018)

micromind said:


> Yeah, it doesn't make sense........8.9A @ 460V is more like 7.5HP.........


Yeah that’s more of a 200 volt motor current.


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## micromind (Aug 11, 2007)

460 Delta said:


> Yeah that’s more of a 200 volt motor current.


I thought the same thing.


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## micromind (Aug 11, 2007)

cmdr_suds said:


> Note the rpms, 2 pole motor, not 4. So the FLAs will be different than standard HP-FLAs


Usually, the current of a 2 pole is lower than a 4 pole. 

Of course, there are multiple exceptions.........lol.


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## gpop (May 14, 2018)

The one that 


460 Delta said:


> Yeah that’s more of a 200 volt motor current.


The one that came out, The new pump and the spare all have the same plates (panel is also labeled with the same info). I wonder if there's some funny maths like the pump is really 7hp but has a curve equal to 3hp the rest is used by the cutter blade. 
I will try finding out when they order another spare what the vendor has to say about it.


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## paulengr (Oct 8, 2017)

gpop said:


> Have you ever seen one short to a phase with out going to ground?


I think it’s been a while since I’ve seen this but here are a couple details you may not realize. First one is turn insulation is very thin. Say we have 48 turns. The coil insulation does not have to be rated 480 V. It only needs to be 10 V. Random wound is a little thicker but you get the idea. Magnet wire insulation is so thin often it’s transparent and you can nick it with a fingernail. That’s why coils look like copper.

Second Klixxons aren’t exactly high current devices. And the knockoffs are even worse. Anything over an amp or two and it’s destroyed. And it is cemented right onto the coils.



http://i.ebayimg.com/images/g/M8kAAOSwHnFVzgKL/s-l300.jpg



Klixxons don’t work fast enough if the motor is locked up. They also don’t pick up on damaged leads or moisture in the peckerhead seals. This is the one time where an external overload is better, and a seal failure relay. But either way if it single phased or locked up eventually the Klixxons would trip.

Going the other way you have a burned up starter coil. Maybe it chattered to death or.maybe the contactor coil just reached end of life. The coil is a fairly high impedance that protects the Klixxon. Without it the Klixxon burned into the motor coil. Since the starter was jammed closed the motor probably then single phased itself to death. Or it might have pumped all the water down and burned up with no water cooling which submersibles need, melting the coil into the Klixxon. Burning coils open without burning out the slot insulation is uncommon but it does happen. It happens a lot more often with surge failures because the damage is usually right at the ends of the coils. A single failure in the middle of a slot is rare but happens from manufacturing errors like defective or nicked insulation...pretty rare and since everything is both turn insulated and varnished/epoxied even such a defect is unlikely to ever cause the motor to fail.

I think Meggering a motor is a good first step but so is checking continuity. You aren’t so much looking for a motor failure because as you said it’s less likely. But breaking a lead in half or failed terminations are pretty common in motors. Megger test may or may not pick it up depending on how it failed. And in a six lead (wye delta) or DC the coils are separate but not any other case. So get in the habit of testing continuity too not just one Megger test. If you do multiple Megger tests and everything isn’t fully discharged you get invalid readings. Another method is purposely connect everything together. An easy way is carry a bunch of alligator clip jumpers. You can buy a set of a dozen test jumpers off Amazon for under $10. Just clip all the leads together with a couple jumpers. Works just as good as relying on the motor as your “jumper”.


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## gpop (May 14, 2018)

Thanks for the reply paul. It makes more sense that the Klixxon wiring burnt into the coil wiring and on this station its defiantly possible using the panel wiring diagram to overload the Klixxon . It also makes it a easy upgrade in the future to add a relay and prevent it happening again.

My mistake was paying attention to the people who had already worked on the station and ignoring my own advice to start at the beginning. The pump with the jammed coil runs fine and tests good. Once the contactor's were removed from the panel both looked like they had screwdriver marks on the front indicating that someone has tried to force the pump to run which makes one of the contractors either very stupid or very brave on a 480v system.


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## just the cowboy (Sep 4, 2013)

Wish I could come help. -10 with -25 real feel here.


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## 460 Delta (May 9, 2018)

gpop said:


> My mistake was paying attention to the people who had already worked on the station and ignoring my own advice to start at the beginning.


I struggle with this same concept more often than I should.


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## paulengr (Oct 8, 2017)

gpop said:


> Thanks for the reply paul. It makes more sense that the Klixxon wiring burnt into the coil wiring and on this station its defiantly possible using the panel wiring diagram to overload the Klixxon . It also makes it a easy upgrade in the future to add a relay and prevent it happening again.
> 
> My mistake was paying attention to the people who had already worked on the station and ignoring my own advice to start at the beginning. The pump with the jammed coil runs fine and tests good. Once the contactor's were removed from the panel both looked like they had screwdriver marks on the front indicating that someone has tried to force the pump to run which makes one of the contractors either very stupid or very brave on a 480v system.


There are times where manually forcing a contactor in is fine. Easy way to check rotation without an HOA switch for instance. And if it sits for a while and gets badly oxidized sometimes it’s the best way to clean it. I prefer to use the back of the screwdriver though. It’s insulated and not sharp.


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## JRaef (Mar 23, 2009)

I think your idea about a hung-up float and chattering the contactor is likely a key element. and it caused the coil to overheat and swell. The other stuff is likely secondary to that.

Pushing a contactor armature in manually and holding it closed is a fool's errand. When current flows through the contacts, there are magnetic forces trying to push them apart. The electromagnet has to maintain enough physical pressure to overcome that force. In anything but the smallest of contactors, you cannot exert enough force manually and even though you may not see it or hear it, manually closing a contactor is allowing the contacts to vibrate and burn, REALLY fast. If you don't believe me, put you fingers under the armature of a Size 2 starter and energize the coil to see if you can exert more force than that coil (Hint; you can't and your fingers will be smashed). Bumping for a rotation check is probably OK, but for anything else, no.


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## just the cowboy (Sep 4, 2013)

Keep your helper he is a thinker. 
We use sacrificial relays everywhere in our well houses and lift stations. It serves two purposes. 
1. visual status of floats and high low pressure for maintenance when troubleshooting. Relay labeled pond high float, ask is relay on better that card 3 light 12. Installing 40 HMI’s in future but this is what we have. 
2. isolation from voltage sources, before PLC. Lightning is our main reason, if a hatch intrusion switch gets hit it only makes it to our relay not PLC Card. But same as klixon in motor or wires in peckerhead. It would protect them.


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## gpop (May 14, 2018)

Newer style panels have all the bells and whistles 










Everything in here is relay protected 










Part of my plc training is to design new HMI screens and add additional code to make the panel self diagnosing so its gone from having 4 pages of screens to 27 as it explains every alarm and the action required to correct the problem. Its still a work in progress as i have to wait for feedback from operations. 

I have 6 more of these panels to install over the next few weeks and a bunch of other work including installing hmi's on panels with plc's.

Friday night was the first time i realized that panel belonged to my department and i have been there 2 years so its not unreliable. I will plan on a few upgrades to keep it running for a few more years then it will get a major upgrade when we switch that area over to radio communication.


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## gpop (May 14, 2018)

Im glad to see you guys notice the value of a good helper/trainee.
Mine came with the job and there was some questions as he's starting out in the industrial field at over 40 years old.
Once i got him to understand that i did not need a ditch digger as im capable of doing that i only had to slow him down and make him think.
I wish i could have taken him to my last job where we had 5 break downs a day as he would have gained so much more experience by now. Instead we spent alot of time working on the bench.

He built his first panel from scratch last year with no prints just a description of what i wanted it to do. Spent a day troubleshooting it as i refused to help other than to answer questions. Then when it worked flawlessly i went in there and played with the wiring/parts and he spent another 2 days fixing what i had done to it.

Funny as hell when he realized that a lot of electricians have no idea how some of this stuff works so hes showing them how to figure out the problem. I nearly wet myself when i overheard him telling the contractor "what does your meter say, Does that sound correct to you".


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## micromind (Aug 11, 2007)

gpop said:


> Newer style panels have all the bells and whistles
> 
> View attachment 153992
> 
> ...


Are those relays the Square D/Telemechanique Zelio type? 

I like those and have been using a lot of them recently. The RPM type is my favorite.


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## gpop (May 14, 2018)

micromind said:


> Are those relays the Square D/Telemechanique Zelio type?
> 
> I like those and have been using a lot of them recently. The RPM type is my favorite.


Schneider electric


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## micromind (Aug 11, 2007)

gpop said:


> Schneider electric


Yep, same thing.....lol.


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