# Bad day at work...how likely is it to get a bad transformer from the manufacturer?



## chicken steve (Mar 22, 2011)

Welcome to ET tvaughan

yes it happens, i can recall one particular bad xformer, caused a lot of problems

we shouldn't have to, but we could meg them out first i suppose

~CS~


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## Big John (May 23, 2010)

6 or 7 years ago I saw a brand new one go bad because of winding failure. I wasn't in the room for it, but they said when it was turned on it looked like a rocket taking off.

It happens. You've got photographic evidence that it was within the winding and not on any field-serviceable parts. I'd those pictures to the supplier explaining you wanted a warrantied replacement, and they might buck you over to the manufacturer.


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## Southeast Power (Jan 18, 2009)

OK,
Now that you have done it, you can write your own start up procedure. You are now completely qualified.


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## varmit (Apr 19, 2009)

I deal with something "defective out of the box" almost monthly it seems. 

From your pictures, there is no normal way to field damage a winding at this location. I have had a transformer that some of the buss welds were so bad that they broke during shipment. You could look at the pieces and see that there was no weld penetration.


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## Bbsound (Dec 16, 2011)

Your project manager may not be happy, but that is beyond your control. 
Just continue to be productive, stuff happens.


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## Zog (Apr 15, 2009)

That is why commisioning tests are a good idea, would have caught that before it blew up. :whistling2:


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## 8V71 (Dec 23, 2011)

Zog or anyone, transformers are not one of my strong points. I'm wondering though, from the pics it looks like the first winding loop from an external termination is burned up. Could an external issue do that?


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## BBQ (Nov 16, 2010)

Zog said:


> That is why commisioning tests are a good idea, would have caught that before it blew up. :whistling2:


Its junk either way


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## stuiec (Sep 25, 2010)

BBQ said:


> Its junk either way


Joe might throw a couple hundo at it.....


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## Cow (Jan 16, 2008)

It's been a few years since we've had a failure right out the box.



Zog said:


> That is why commisioning tests are a good idea, would have caught that before it blew up. :whistling2:


Our commissioning test is throwing the breaker on.....:thumbsup:


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## CFL (Jan 28, 2009)

Cow said:


> It's been a few years since we've had a failure right out the box.
> 
> 
> 
> Our commissioning test is throwing the breaker on.....:thumbsup:


My boss would probably tell me to throw on the breaker even if it failed the commissioning test. "Let's just see what happens...":thumbsup:


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## Big John (May 23, 2010)

CFL said:


> My boss would probably tell me to throw on the breaker even if it failed the commissioning test. "Let's just see what happens...":thumbsup:


 I think I've worked for your boss before. First doing the commissioning, and then doing the repairs. :whistling2: :laughing:


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## tvaughan (Jul 14, 2013)

Well, had a Siemens rep come out to my job today to take a look at the transformer. He thinks that it was a faulty coil and the failure had nothing to do with our work. Im not sure how the coils are constructed but he said he thought that there is a weld between the H terminal and the actual coil. The weld must not have made a good connection and caused it to arc and start melting the insulation on the coil. When I turned the transformer on I was at the switchgear and I had a guy getting ready to check voltage at the new panel. I only had the breaker on for about 15 seconds before he radioed me to turn it off. The breaker never tripped. Anyways, our supplier will be sending it back to Siemens so they can tear it apart and find out exactly what happened. Now I get the fun of installing this transformer all over again...


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## frenchelectrican (Mar 15, 2007)

Useally the transfomer like that big will useally do more damage than you expected to be. But you are lucky that you turn it off before it get more damage there.

I have few near miss with the transfomer go bad on me so that one rules I always do before I ever engerized even for the first time is run the megger to make sure it is ok before you throw the power source on first time.

Merci,
Marc


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## 8V71 (Dec 23, 2011)

tvaughan said:


> Well, had a Siemens rep come out to my job today to take a look at the transformer. He thinks that it was a faulty coil and the failure had nothing to do with our work. Im not sure how the coils are constructed but he said he thought that there is a weld between the H terminal and the actual coil. The weld must not have made a good connection and caused it to arc and start melting the insulation on the coil. When I turned the transformer on I was at the switchgear and I had a guy getting ready to check voltage at the new panel. I only had the breaker on for about 15 seconds before he radioed me to turn it off. The breaker never tripped. Anyways, our supplier will be sending it back to Siemens so they can tear it apart and find out exactly what happened. Now I get the fun of installing this transformer all over again...


A bad connection crossed my mind but I couldn't see if the coil material went straight to the terminal or if there was a wire attached to it. I thought it was odd that the first winding loop would heat up like that.


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## kbsparky (Sep 20, 2007)

tvaughan said:


> .... When I turned the transformer on I was at the switchgear and I had a guy getting ready to check voltage at the new panel. I only had the breaker on for about 15 seconds before he radioed me to turn it off....


No disconnecting means within sight?


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## Jlarson (Jun 28, 2009)

Zog said:


> That is why commisioning tests are a good idea, would have caught that before it blew up. :whistling2:


It does avoid those pesky "it looked like a rocket taking off" moments while you are standing right next to the thing.


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## BBQ (Nov 16, 2010)

Jlarson said:


> It does avoid those pesky "it looked like a rocket taking off" moments while you are standing right next to the thing.


You say pesky I say invigerating


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## tvaughan (Jul 14, 2013)

kbsparky said:


> No disconnecting means within sight?


No the only disconnect is in the basement at the main switchboard. I've been meaning to look that up in the code book. I talked to my inspector and he said as long as there is a permanent lock out attached breaker it is ok. What I mean is as long as you can open the breaker and lock it out with out adding an external lockout device.


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## tvaughan (Jul 14, 2013)

Article 450.14


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## Jlarson (Jun 28, 2009)

BBQ said:


> You say pesky I say invigerating


Until you are in a burn ward :laughing:


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## papaotis (Jun 8, 2013)

kbsparky said:


> No disconnecting means within sight?


 goob point kb:no:


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## ponyboy (Nov 18, 2012)

papaotis said:


> goob point kb:no:


Don't need it


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## BBQ (Nov 16, 2010)

Jlarson said:


> Until you are in a burn ward :laughing:


When did you become a *****?:laughing:


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## Jlarson (Jun 28, 2009)

BBQ said:


> When did you become a *****?


Go fix a cotton candy machine carny :laughing:


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## BBQ (Nov 16, 2010)

Jlarson said:


> Go fix a cotton candy machine carny :laughing:


Melted sugar is nothing to joke about. 
















:jester::laughing:


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## sparky970 (Mar 19, 2008)

tvaughan said:


> Alright, Im currently working on a electrical infrastructure upgrade on a local high school. This project includes replacing eight transformers in different areas around the school along with changing out existing panels and feeders. So far we have replaced five of them with out any problems at all. Friday we went to turn on our last transformer of the current outage and the thing blows up. From the looks of it, there was some sort of short in one of the coils. It really wasn't bad and no one was hurt but I cant stop thinking about it and what could have went wrong to cause this to happen. Needless to say we have to get a new transformer and my project manager is not very happy. I have been in the trade for seven years and recently made it to a foreman position in my company. I have two guys working with me who I really trust but ultimately this accident falls on my shoulders. Its my responsibility to get the job done right and safely. I just cant see how this would have been our fault but have never heard of a brand new transformer being delivered defective from the manufacturer. We've been installing Siemens products and this particular transformer was a 112.5KVA 480/208/120. I guess Im asking if anyone else has heard of this happening before...




Did you megger anything before you energized


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## Jlarson (Jun 28, 2009)

BBQ said:


> Melted sugar is nothing to joke about.



:laughing::laughing: Yeah sugar!


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## tvaughan (Jul 14, 2013)

Nope no megger. But you better believe I do now... Just turned on another transformer today and I made sure I did before we turned it on.


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## sparky970 (Mar 19, 2008)

tvaughan said:


> Nope no megger. But you better believe I do now... Just turned on another transformer today and I made sure I did before we turned it on.


Why not? Always megger a new or used one, as well as the wire. We see specs that say to megger upon delivery and after install. Maybe yours was bad when it showed up. Maybe it got damaged after you handled it. How do you know?


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## ponyboy (Nov 18, 2012)

sparky970 said:


> Why not? Always megger a new or used one, as well as the wire.


I couldn't even tell you how many transformers I've installed without megging (all new out of the box). Seems stupid now, starting tomorrow I'm a new man


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## sparky970 (Mar 19, 2008)

ponyboy said:


> I couldn't even tell you how many transformers I've installed without megging (all new out of the box). Seems stupid now, starting tomorrow I'm a new man


My customers are all industrial. They always ask for megger sheets. For us its standard practice.


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## ponyboy (Nov 18, 2012)

sparky970 said:


> My customers are all industrial. They always ask for megger sheets. For us its standard practice.


The place I work has megger sheets for everything but transformers


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## Jlarson (Jun 28, 2009)

We meg xformers as soon as the forklift sets the pallet down. Same with motors. That way if it's busted we can send it right back and get angry with the supplier. :laughing:


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## frenchelectrican (Mar 15, 2007)

Jlarson said:


> We meg xformers as soon as the forklift sets the pallet down. Same with motors. That way if it's busted we can send it right back and get angry with the supplier. :laughing:


 
That pretty much my SOP over here in France we have to megger almost everything we touch.

The moteur and transfomers are two biggest headaches we have do them first before they ever bring in the final location ( they can be pain in arse if you find out they don't pass the test. )

Once you get good with megger it will not take very long to do the whole thing.

Merci,
Marc


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## frenchelectrican (Mar 15, 2007)

tvaughan said:


> Nope no megger. But you better believe I do now... Just turned on another transformer today and I made sure I did before we turned it on.


Now you know why some of us will do the megger test first before we ever engerized them first time it don't matter if new or used transfomers.

That way we can catch the bad one before they do pretty good damage.

Merci,
Marc


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## Big John (May 23, 2010)

Just got back from commissioning a 2.5MW generator. Stator and rotor where shipped in on the back of a flatbed. Go out to talk to the driver about rigging and see that it's completely uncovered.

"Did you uncover that?"
"No."
"You drove all the way up here with that uncovered...?" :blink:
"You bet."
"Took a big chance with the weather, didn't you?"
"Oh, yeah. And it rained like hell the whole way!" 
"It rained? Like hell...?" :icon_eek:
"You bet! Worst storm I've seen in years."

We woulda megged it regardless, but when the crane picks it and dirty water pours out... "I think we're gonna need a bigger megger." :whistling2:


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## sparky970 (Mar 19, 2008)

Big John said:


> Just got back from commissioning a 2.5MW generator. Stator and rotor where shipped in on the back of a flatbed. Go out to talk to the driver about rigging and see that it's completely uncovered.
> 
> "Did you uncover that?"
> "No."
> ...


Is this a joke?


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## Big John (May 23, 2010)

sparky970 said:


> Is this a joke?


 The part about needing a bigger megger is. The rest, unfortunately, is not.

I like to think nobody in their right mind would've energized a piece of equipment when they saw water pouring out of it, but things like this are also the reason for commissioning.


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## sparky970 (Mar 19, 2008)

Big John said:


> The part about needing a bigger megger is. The rest, unfortunately, is not.
> 
> I like to think nobody in their right mind would've energized a piece of equipment when they saw water pouring out of it, but things like this are also the reason for commissioning.


What were the results?


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## Big John (May 23, 2010)

sparky970 said:


> What were the results?


 The lowest one was 30,000Ω and this was a 5kV machine. You do the math. :whistling2: The initial resistance was so bad that when we did a pole-drop test there was enough ground-fault current to trip a GFCI at 120V.


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## sparky970 (Mar 19, 2008)

Big John said:


> The lowest one was 30,000Ω and this was a 5kV machine. You do the math. :whistling2: The initial resistance was so bad that when we did a pole-drop test there was enough ground-fault current to trip a GFCI at 120V.


Were you able to clean and dry it? I would think a good rinse in DI water and an oven.


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## 8V71 (Dec 23, 2011)

Gonna need a bigger oven.


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