Favor --- looking for electrical engineer/contractor who knows about transformers
#1
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Favor --- looking for electrical engineer/contractor who knows about transformers
Hi-
Mods, please accommodate me on this off subject post and don't delete for a few days.
I'm consulting on the construction of a small hospital, and am being asked power plant questions beyond my expertise. The current one relates to the substation and the transformers needed, wet vs. dry.
If anyone has expertise in the field and wants to help me, please PM or email me through the forum.
Thanks
Mods, please accommodate me on this off subject post and don't delete for a few days.
I'm consulting on the construction of a small hospital, and am being asked power plant questions beyond my expertise. The current one relates to the substation and the transformers needed, wet vs. dry.
If anyone has expertise in the field and wants to help me, please PM or email me through the forum.
Thanks
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FB
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#2
incazzare.
Can you hire a consultant and bill it back? If so I could recommend some people. On these kinds of things people don't like to stick their necks out too much.
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#3
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You could also post in Foo ... a broad range of people hang out there.
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#4
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Try the IBEW > Home
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Transformers - More than meets the eye.
Hope that helps...
Hope that helps...
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Today, I believe my jurisdiction ends here...
Today, I believe my jurisdiction ends here...
#6
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Not really, but I'll have a coupla of beers and see if that helps.
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FB
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#8
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I thought they were all oil filled past a certain size. The tranformers we have in the lab get hot, I can't see air removing the heat properly
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Hi-
Mods, please accommodate me on this off subject post and don't delete for a few days.
I'm consulting on the construction of a small hospital, and am being asked power plant questions beyond my expertise. The current one relates to the substation and the transformers needed, wet vs. dry.
If anyone has expertise in the field and wants to help me, please PM or email me through the forum.
Thanks
Mods, please accommodate me on this off subject post and don't delete for a few days.
I'm consulting on the construction of a small hospital, and am being asked power plant questions beyond my expertise. The current one relates to the substation and the transformers needed, wet vs. dry.
If anyone has expertise in the field and wants to help me, please PM or email me through the forum.
Thanks
#10
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Your issue goes beyond your transformer question.
the NEC (national electric code) has a whole section on hospital requirements and there's a whole set of state regulations on top of that.
in California it's OSHPD. but every state will have it's own regulatory body.
Uou don't need the IBEW, you need a registered electrical engineer in your state with verifiable hospital regulation experience Just having a PE stamp isn't enough.
CA C-10 for 30+ years.
the NEC (national electric code) has a whole section on hospital requirements and there's a whole set of state regulations on top of that.
in California it's OSHPD. but every state will have it's own regulatory body.
Uou don't need the IBEW, you need a registered electrical engineer in your state with verifiable hospital regulation experience Just having a PE stamp isn't enough.
CA C-10 for 30+ years.
Last edited by TGT1; 09-29-15 at 07:48 PM.
#11
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Guys, this is in Mexico where things are a bit different. Yes, there are regulations, which are similar to those in the USA though not identical. I'm not doing the basic engineering, that's the job of a local EE/contractor. But there is some room for discretion, and conforming transformers in the range we need come in both dry and wet versions. So it's a question of a choice, and which would be best and why.
I'm not directly involved with that phase of the project, but there's a certain level of distrust between the owners and the engineer who is also the contractor. I was asked to help the owner weigh the advice and better understand the why's and wherefores.
I already know that larger transformers bias toward wet, and smaller to dry, but we're mid-spectrum and can go either way. It's a cost/benefit issue, along with one of trust.
In a way it's like the bike issue where someone is buying a new bike and the dealer is pushing Campy, and he wants to know if a less costly Ultegra group would do the job.
I'm not directly involved with that phase of the project, but there's a certain level of distrust between the owners and the engineer who is also the contractor. I was asked to help the owner weigh the advice and better understand the why's and wherefores.
I already know that larger transformers bias toward wet, and smaller to dry, but we're mid-spectrum and can go either way. It's a cost/benefit issue, along with one of trust.
In a way it's like the bike issue where someone is buying a new bike and the dealer is pushing Campy, and he wants to know if a less costly Ultegra group would do the job.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 09-29-15 at 08:12 PM.
#12
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so how much does it save to go dry? I live on a street where the transformers go bang every once in a while, and I'm pretty sure the transformers in a hospital are bigger than that. You want to avoid explosions if possible.
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under 600V, it's a no brainer, Dry
Over 4160V no brainer for oil filled
Oil filled pad mount outside the building, no brainer.
An oil filled transformer is basically a fire bomb waiting to go off so if it is inside the building it must be in a specially constructed fire proof room.
They are called "transformer vaults" for a reason.
If your engineer/contractor is pushing for oil filled in a one to one replacement for dry in a hospital without the required fireproof enclosures (concrete and rebar with fire doors and drains etc) that's approaching criminal behavior.
Over 4160V no brainer for oil filled
Oil filled pad mount outside the building, no brainer.
An oil filled transformer is basically a fire bomb waiting to go off so if it is inside the building it must be in a specially constructed fire proof room.
They are called "transformer vaults" for a reason.
If your engineer/contractor is pushing for oil filled in a one to one replacement for dry in a hospital without the required fireproof enclosures (concrete and rebar with fire doors and drains etc) that's approaching criminal behavior.
Last edited by TGT1; 09-29-15 at 08:36 PM.
#14
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under 600V, it's a no brainer, Dry
Over 4160V no brainer for oil filled
Oil filled pad mount outside the building, no brainer.
An oil filled transformer is basically a fire bomb waiting to go off so if it is inside the building it must be in a specially constructed fire proof room.
They are called "transformer vaults" for a reason.
If your engineer/contractor is pushing for oil filled in a one to one replacement for dry in a hospital without the required fireproof enclosures (concrete and rebar with fire doors and drains etc) that's approaching criminal behavior.
Over 4160V no brainer for oil filled
Oil filled pad mount outside the building, no brainer.
An oil filled transformer is basically a fire bomb waiting to go off so if it is inside the building it must be in a specially constructed fire proof room.
They are called "transformer vaults" for a reason.
If your engineer/contractor is pushing for oil filled in a one to one replacement for dry in a hospital without the required fireproof enclosures (concrete and rebar with fire doors and drains etc) that's approaching criminal behavior.
In any case, I think I have enough info to give the owners, who can now ask more pointed questions and get the answers that will (hopefully) make them more comfortable with the proposal.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#15
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Really isn't much to add here.
Oil-filled units - with their better cooling - can be made smaller, which is "good". But might not be important for your particular application.
But since they need to be kept filled, more engineering has to go into their casings - which is "bad".
The oil in itself can be quite nasty to deal with - which is bad.
Although the oldest guys at my first job always kept some that they used as hand lotion...
And they need to be checked, topped up, have desiccants refreshed etc. etc. which is "bad".
And - depending on local laws - might need their foundations doubling as catch basins in case of an oil leak.
Looking at installation cost, definitely a "bad".
Dry gives you bigger units, less maintenance, no special foundation requirements.
For an equal level of engineering (margins), both should work fine.
Best as I recall, wet units CAN be rated for "indefinite" life.
Meaning there's no functionally important ageing going on as long as they are properly maintained and left within their stated operating range. Dry units MAY have a defined life due to degradation of the insulation. Meaning eventual replacement is unavoidable regardless what.
Oil-filled units - with their better cooling - can be made smaller, which is "good". But might not be important for your particular application.
But since they need to be kept filled, more engineering has to go into their casings - which is "bad".
The oil in itself can be quite nasty to deal with - which is bad.
Although the oldest guys at my first job always kept some that they used as hand lotion...
And they need to be checked, topped up, have desiccants refreshed etc. etc. which is "bad".
And - depending on local laws - might need their foundations doubling as catch basins in case of an oil leak.
Looking at installation cost, definitely a "bad".
Dry gives you bigger units, less maintenance, no special foundation requirements.
For an equal level of engineering (margins), both should work fine.
Best as I recall, wet units CAN be rated for "indefinite" life.
Meaning there's no functionally important ageing going on as long as they are properly maintained and left within their stated operating range. Dry units MAY have a defined life due to degradation of the insulation. Meaning eventual replacement is unavoidable regardless what.
#16
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Really isn't much to add here.
Dry gives you bigger units, less maintenance, no special foundation requirements.
Best as I recall, wet units CAN be rated for "indefinite" life.
Meaning there's no functionally important ageing going on as long as they are properly maintained and left within their stated operating range. Dry units MAY have a defined life due to degradation of the insulation. Meaning eventual replacement is unavoidable regardless what.
Dry gives you bigger units, less maintenance, no special foundation requirements.
Best as I recall, wet units CAN be rated for "indefinite" life.
Meaning there's no functionally important ageing going on as long as they are properly maintained and left within their stated operating range. Dry units MAY have a defined life due to degradation of the insulation. Meaning eventual replacement is unavoidable regardless what.
Oil has a longer lifespan but will need to be replaced eventually. Do you have to deal with accreditation inspections or approvals like we do here?
#17
Senior Member
BWe Megged them and drew oil samples yearly. As long as that was OK compared to the manufacturer's plate, they were considered OK for another year. 40+ years and counting. Probably they'd end up replaced eventually out of sheer embarrassent, even if the engineering still held up.
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Does that mean Chain-L filled? (sorry could not resist)
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#19
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Dammit, now the whole world knows what's in Chain-L.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#20
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I've purchased both wet and dry transformers installed in Mexico. Do yourself a favor: hire a proven specialist to provide answers you can sleep on. If you don't like them, hire a different one. You can't get what you don't pay for.