# I got woke up in the middle of the night with this



## macmikeman (Jan 23, 2007)

Call came in at 2:30 am which is a half hour ago. 20 story building. Maintenance manager says water went out in the building, got the leak repaired by city and county water. Went to restore service at the pump . Soon as he turned on the safety switch in front of the drive he heard a loud pop . So he moved on over to the backup pump and turned on the SS handle and heard the same sounding pop on that one. Neither drive came on . I got a call from him shortly thereafter. I am heading over there now . I have no idea what voltage , etc those pumps are , having never seen them even. 

But any tips, tricks, or magic words you have for me will be appreciated to the fullest . I'm bringing the laptop along for the ride ................. 

If the voltage for the motors is over 600 I call in outside help regardless......


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## gpop (May 14, 2018)

You said drives. If you are referring to vfd's then go to the allen bradley site and make a log in then look for how to test a drive with a meter. 
They have instructions on how to test the components of a drive diodes, gates etc


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## pjones (Oct 7, 2019)

“Safety switch In front of the drive” can mean anything when coming from untrained personnel. 

Got any updates or more specific/confirmed information?


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## Wirenuting (Sep 12, 2010)

Put one in bypass until you fix the other. 
It should be looped so the pressure don’t go to high. 
Watch the back-flow-preventer for water coming out the relief.


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## John Valdes (May 17, 2007)

Did they get wet? You said water leak?
If so the drives need to be replaced or repaired (dried out and tested).
What size are the drives?
Do you have a megger and a good meter?
You can find the issue if you have the ability to test the drive and the motor very easily.

Once you find out or cannot find out see if there is a motor shop in the area. Good shops have service guys that know the drives and the motors.
Good luck.


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## micromind (Aug 11, 2007)

If the disconnect switches are downstream of the VFDs, and the VFDs were on at the time, then both VFDs are now trash........

Closing a motor in to an operating VFD will often blow the output transistors.


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## micromind (Aug 11, 2007)

Double post.


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## JRaef (Mar 23, 2009)

If the disconnects are ahead of the drives and the drives went "pop" when the power came on, they are likely toast too. About the only thing that would make a popping sound in a drive is either a direct short to ground inside of the drive, i.e. it got wet, or the caps have exploded, i.e. there was a severe surge right before the power went out, which damaged the drives and when re-powered, the caps blew.


Either way, same fix; replace them.


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## macmikeman (Jan 23, 2007)

Ok, I'm home now. So what he tells me on the phone and what I find is two different stories. Those pumps are for all the floors above #11- including the toilets and sinks in hallway bathrooms, and any breaksinks and the like up there. They supply water to the upper floors. 

There was two pumps and two VFD's , the two pumps were 7.5 horse not 10's. There is a pump control panel that alternates the two drives depending on pressure build ups in different pipes and a few other factors. The Pop's were the fuses blowing. 


Here is what I did... Get there, talk to maintenance manager about what happened and what is supposed to happen. Crews were working on improving chilled water system and had shut down water that day earlier. ( or it was I guess the day before.... but I digress.....) So when Manager went to restore the pumps after opening up the correct valves is when he heard the loud pops. Both vid's are in off position on built in selector switches on front cover. There is no safety switches at all, he just called em that to me on the phone. I located power source circuit breaker, turned off power, checked for that and then checked incoming line wiring for any shorts or opens. All good so far. So then I open all the splices from the feed wires to the motor windings connections and first check ohms between motor windings conductors and ground, and also checked ohms between winding wires A, b, and C. Both motors. All windings good. Next megger test windings to ground. Tested the fuses inside the drives, both drives had blown fuses in phase b and phase c. Take a road trip with maintenance manager in pursuit of SSL-25 I believe it was fuses. Found a vendor with a box of ten , so we bought that. Removed fuses in both drives and then energized the one main breaker for both pumps. No. booms. Thinking now- we have bad vid's. Told manager- call another more modern motor control outfit cause I ain't trained in how to fix your drives. They are Danfoss VLT 8000'S by the way. We had no manuals either. I know the guy to call so we called him in. He spends a while troubleshooting and finds water intrusion clues in the left hand drive , but the right hand side looks ok at first. So he opens all quick connects, checks everything, opens this , opens that, declares left side machine smoked, right side machine he thinks is going to be fine. So we put it all back together, leave drive 1 off, fuses removed, and fire up #2. The display lites up fine and he gets a chance to check all the settings and codes. Things are going real good , at least we have one pump working fine so we get happy. Then five minutes in ... Boom again and drive #2 drops out. Drive tech says he is going to find replacements. Blames this hoakey drip pan up above the drives and controller box made of that rain gutter type of covering channels the AC companies like to cover their piping jobs up the side of buildings with. I agree with him the drip pan job was a joke. We figured the restoration of the chilled water system must have resulted in condensation on the water pipes exposed right above where the drives were. some drips must have gotten into the drive units. Moisture kills drives. 

Meanwhile while all this is happening the plumbing company working on chilled water systems in the same mechanical room - the helper setting 1/2' DROP ANCHORS up into concrete ceiling of the ground floor mechanical room, drills thru an electrical conduit with his rattle gun. Bigger boom. And about 1/2 of the first two floors are now without lights or receptacle outlet power. So I got to spend the rest of the day chasing around that one trying to find out what breaker it is , what loads it serves and so forth so we can return power on. What a day. 
The uncoordinated breaker system - blows a breaker in the MDP and it is old and now won't restore when you reset the handle. Three breaker panels are affected, one a 480 panel serving lights and a bunch of other stuff including a transformer primary that bucks the 480 down to 208/120 serving the other two panels, which both have next to zero circuits marked. I have to go back in a few hours , we are gonna shut down the entire building, swap out the breaker in the MDP, trace out the drilled circuit somehow using my wand and tone generators. I hope. Wish me luck. I'm gonna need some.


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## A Little Short (Nov 11, 2010)

Good luck with that.
Please pick up a new "enter" button for your keyboard while you're out.
That hurt my head to read!


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## Switched (Dec 23, 2012)

A Little Short said:


> Good luck with that.
> Please pick up a new "enter" button for your keyboard while you're out.
> That hurt my head to read!


click... click... boom


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## macmikeman (Jan 23, 2007)

A Little Short said:


> Good luck with that.
> Please pick up a new "enter" button for your keyboard while you're out.
> That hurt my head to read!



2:30 am getup and go to a job. Return home at around 5:45 pm . You try making it look good.


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## A Little Short (Nov 11, 2010)

macmikeman said:


> 2:30 am getup and go to a job. Return home at around 5:45 pm . You try making it look good.



Surfs up!


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## zac (May 11, 2009)

macmikeman said:


> 2:30 am getup and go to a job. Return home at around 5:45 pm . You try making it look good.


Somebody call the whambulance! 

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## gpop (May 14, 2018)

rule of thumb on vfd's from experience.
Blow one fuse it might be ok. (mov dumped a spike)
blow 2 fuses you had better do a meter test on the drive as its probably toast.
If you heard the fuse pop that's real bad
If you tripped a breaker its normally a done deal just test with a meter for fun.


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## paulengr (Oct 8, 2017)

gpop said:


> rule of thumb on vfd's from experience.
> Blow one fuse it might be ok. (mov dumped a spike)
> blow 2 fuses you had better do a meter test on the drive as its probably toast.
> If you heard the fuse pop that's real bad
> If you tripped a breaker its normally a done deal just test with a meter for fun.




If you have a motor short or go to ground depending on the transformer size and drive size you will blow fuses too. So megger motor and milliohm meter phases after disconnecting drive. Just do it right at the drive to test the cable too.

Ohm checks on drive? Anything other than the diode test? You can’t test the transistors at least on small or most modern drives because you don’t have access to the gates.

For breakers read NEMA AB-4. There is a 60 second test you are supposed to do every time before resetting. Every single molded case breaker company references this standard. It’s mostly pictures pointing out what to look for. And ohming is part of it. That’s the best way to find welded phases. And I know it’s all plastic but ohm to ground too. Found that happened more than once as it blew carbon and metal out the back instead of through the vents or around the handle.


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## macmikeman (Jan 23, 2007)

Drives are both shot. The one on the left had visible greasy moisture inside behind the display cover. The second one was drier but already damaged by the same thing. I megged the motor's myself. They are good. I brought in my friend who only takes care of VFD's for a living. I did that because I didn't have time to do the research on the units, nor were there any onsite docs regarding the units. After I sent him a few pictures of the units before he came out, he showed up with the proper manuals for the exact units, and did the inspections using a pre-fabricated checklist that gave exact numbers to look for with his Fluke meters. 

The next two days the building management is going to be spending time to remove a remarkably stupid drain tray system under the large water pipes that run along the walls directly above the drive, previously slapped together (a janitor had done the work using ty wraps and plastic gutter . The new one will be fabricated by a sheet metal shop with copper and solder. The very first time I walked into that room there was a big water puddle on the floor in the area of the two pumps and two drives. I knew first thing this was going to be a water issue.

I brought in our local version of Jraef right away instead of me trying to blindly go at it like a donkey. I'm glad I did. He thinks he can scrape together replacements probably today of brand new drives to fit the situation. Otherwise they are going to fly in some pronto. I will end up mounting and wiring in , and he will be the one to get it all started up and going. I'm good with that.


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## macmikeman (Jan 23, 2007)

As far as item number two- at same location. I returned to the site at 8:30 pm after a few hours rest at home. We shut the entire building down , including FA , backup generator system, elevators , everything. Only the exit lights and emergency lights with backup batteries were on in the whole building. Traced down the source breaker for the shorted wires in the deck slab in under a half hour. There is no less than twenty different panels in the area, no branch breakers had tripped, just the one 400 amp three pole 480 distribution breaker in the MDP. I opened the MDP all up - a two man job if I ever saw one and viola- the 400 amp breaker was double tapped. 3 number 12 wires bootlegged into the lugs going up into a 3/4" emt conduit running out of the top of the MDP straight up into the concrete deck of the floor above. They are the ones that got drilled by the plumber. I just taped em off , restored power to building after putting all the covers back on , and spent another hour and a half looking at all the systems and various "things" in the building to try to find what isn't working now. So far no luck, we called it a day at 11:00 pm. If it is important they will find it this morning. It very well may be something old and abandoned, there seems to plenty of that going on there. I hate jackass wiring. I just hate it. 
I also am not real thrilled about plumbers right now, but in their defense that conduit was no more than an inch into the concrete of the deck so all the way back to the day they made that building in the first place , improper work was allowed and paid for. lain:


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## gpop (May 14, 2018)

macmikeman said:


> Drives are both shot. The one on the left had visible greasy moisture inside behind the display cover. The second one was drier but already damaged by the same thing. I megged the motor's myself. They are good. I brought in my friend who only takes care of VFD's for a living. I did that because I didn't have time to do the research on the units, nor were there any onsite docs regarding the units. After I sent him a few pictures of the units before he came out, he showed up with the proper manuals for the exact units, and did the inspections using a pre-fabricated checklist that gave exact numbers to look for with his Fluke meters.
> 
> The next two days the building management is going to be spending time to remove a remarkably stupid drain tray system under the large water pipes that run along the walls directly above the drive, previously slapped together (a janitor had done the work using ty wraps and plastic gutter . The new one will be fabricated by a sheet metal shop with copper and solder. The very first time I walked into that room there was a big water puddle on the floor in the area of the two pumps and two drives. I knew first thing this was going to be a water issue.
> 
> I brought in our local version of Jraef right away instead of me trying to blindly go at it like a donkey. I'm glad I did. He thinks he can scrape together replacements probably today of brand new drives to fit the situation. Otherwise they are going to fly in some pronto. I will end up mounting and wiring in , and he will be the one to get it all started up and going. I'm good with that.


The greasy moisture is a sign the caps popped. First time i was confused to see liquid running out of the bottom of a drive."hmm oil cooled"...:vs_laugh:

There's no problem call in the pro's when it comes to drives you was lucky to be able to get one with out having to wait a few days. 
Its also good that you got to see how to test a drive with a meter to confirm its status rather than throwing power to it and hoping that it will work. 
One day you may get stuck with a call like this and no one available to call so learn what you can and hope you never have to use it.


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## pjones (Oct 7, 2019)

macmikeman said:


> ...
> 
> I also am not real thrilled about plumbers right now, but in their defense that conduit was no more than an inch into the concrete of the deck so all the way back to the day they made that building in the first place , improper work was allowed and paid for. lain:



Sounds like it could have happened to anyone. Unless you scan every hole before you drill it then it’s a pretty easy mistake to make. Easy to hate on the person who did it but in reality it was the electrician who put the conduit too close in the first place. The plumber just happens to be the one who found it. They probably aren’t too happy with electricians right about now.




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## JRaef (Mar 23, 2009)

Moisture + VFDs = trouble. I am constantly preaching what I call the "CDC" of successful drive use:


Keep your drives



 *C*lean
 *D*ry
 *C*ool
 Side note: 

Gotta love those jobs where you get called out for one thing and another project pops up for you while you are there. They don't shop around when that happens...


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## LARMGUY (Aug 22, 2010)

Good job Mike!

At least you know what company to send the bill to.


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