Shot blast in transformer; IR good so ok to energize?
Shot blast in transformer; IR good so ok to energize?
(OP)
Installing a new 5MVA ONAN 22-11kv transformer known to have 1-2kg of shot blast sitting in the bottom of the tank. IR between lv-hv was still good so manufacturer says ok to energize. Can anyone foresee any problems if energized.






RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
If it were a bigger transformer,you could have entered inside and cleaned the mess.
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
Bill
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"Why not the best?"
Jimmy Carter
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
You can find one in your area at www.netaworld.org
RE: Shot blast in transformer; IR good so ok to energize?
I would consider this a warranty type issue.
My concern would also be shot lodged in coils and moving around due to the natural core vibrations and thermal convection. Conceivably, this can lead to errosion of coil insulation and an eventual fault.
What happens when the unit fails after the warranty expires after you knowingly accepted the transformer from the manufacturer and energized it in this condition?
RE: Shot blast in transformer; IR good so ok to energize?
Tell the manufacturer to take it back and fix it.
Ask for an extended warranty (say 10 years) on the transformer - and get it in writing.
There is no way I'd accept a screw-up like this without some kind of compensation.
RE: Shot blast in transformer; IR good so ok to energize?
i can not agree more with wbd. i just can't understand why the manufacturer would go ahead in energizing the unit knowing fully well of the situation. this would be a warranty liability issue in the future. are you ready to take the risk?
capuchi
RE: Shot blast in transformer; IR good so ok to energize?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Shot blast in transformer; IR good so ok to energize?
* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *
RE: Shot blast in transformer; IR good so ok to energize?
Are you "shocked" by the posts here ?
Seriously though, IR value is just one measure of winding health. These damned shot blast pellets could get in between the turns of the coils due to oil circulation and damaged the turn insulation due to the mechanical forces during load cycle.
If it is a new trafo, time to hold the manufacturer's toes to the fire on this. Blast them all !!!
* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
Big question to me is why do you need to shot-blast any part of a NEW transformer? Are they using scrap metal to built it? Did they leave the core out in the rain at some point? Odd for me.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Shot blast in transformer; IR good so ok to energize?
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If we learn from our mistakes I'm getting a great education!
RE: Shot blast in transformer; IR good so ok to energize?
RE: Shot blast in transformer; IR good so ok to energize?
Why? It is indicative of poor QA and is likely to constitute a latent defect which will cause a problem after a period in service. The shot is not something which is designed to be in the transformer and is therefore a contaminant. If the manufacturer expects you to keep this transformer then it should at their risk, so if it fails and causes an outage or blows up and kills somebody then the manufacturer carries all liability. It seems you're looking for reasons to keep it, and I can't really see any. It is poor workmanship and should be corrected.
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If we learn from our mistakes I'm getting a great education!
RE: Shot blast in transformer; IR good so ok to energize?
You seem to take the sincere advice given by many experts here lightly. Yes, I am transformer/motor/generator repair man in a "third world" and I wouldn't have allowed this trafo leave my shop.
You don't seem to get that the normal tests and routine tests will not detect this problem. This will develop into a failure at a later date due to reasons given above and I have seen serious trafo failures turn fatal.
If you are looking for some justification to keep this trafo, this would not be the right place, IMO.
Good luck.
* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *
RE: Shot blast in transformer; IR good so ok to energize?
I would backcharge the original manufacturing for all the cost.
You might want to check with your insurance company. The thing is a time bomb. The cost of keeping it may be very high. You are potentilaay looking at a fire and maby some expensive down time.
The thing was poorly or delibertly sabatoged.
RE: Shot blast in transformer; IR good so ok to energize?
Would you insist on some form of 'testing' if you looked in there and saw 300 gallons of dirty water with dead rats floating on the surface? Or cut windings? No! You would not bother. Same with the steel shot...
Keith Cress
kcress - http://www.flaminsystems.com
RE: Shot blast in transformer; IR good so ok to energize?
Dead rats ? Probably shot by them damned pellets ?
* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *
RE: Shot blast in transformer; IR good so ok to energize?
Keith Cress
kcress - http://www.flaminsystems.com
RE: Shot blast in transformer; IR good so ok to energize?
(Damn.. Just when I thought I had mastered TGML code for color, I find them smileys are still out there to conquer, sigh)
* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *
RE: Shot blast in transformer; IR good so ok to energize?
I highly doubt it will pass.
RE: Shot blast in transformer; IR good so ok to energize?
Notwithstanding, if there is still shot in the transformer (contaminated or not), how can you be sure that the scale has been removed, rather than left lying in the bottom of the tank?
I would suggest that the test that will detect this will be oil quality tests over a period of years. The transformer may very well last for enough years before failure that a warranty claim is impossible.
The safe action may be to de-tank and de-grease.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Shot blast in transformer; IR good so ok to energize?
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: Shot blast in transformer; IR good so ok to energize?
cheers