All the ones I've worked on, both dry type and oil filled, actually had totally separate circuits for the cooling fans supplied from the substation service, so they weren't directly connected to the distribution transformer at all.

They may make transformers that have a built in winding to supply auxiliary power, I just haven't seen one yet.

On our larger oil cooled units the fans are 3 phase but we also have some 10MVA dry types that have a bunch of 480V single phase fans. All the motors are fractional horsepower, with the largest being 3/4HP if I remember right.

-John

 

They're 13.8 kV fan motors. Duh.

 

DO they sell them at the home dumbo? :laughing:

~Matt

 

I dealt with a few REM transformers that had 120V fans in them, and even had a little cabtyre cord to plug into a wall socket for the fans. Factory original.

 

The ones I've seen are 120 1ø or 480 3ø. They're fed from a panel in the control house. Just a basic circuit, nothing special.

 

Those things are huge.

163 tons.
Holds 13,000 gallons, or two fuel tanker full of transformer oil.
A lot of big radiator fans

 

Neat, I love that chit. I've never seen a sprinkler system set up on an outdoor transformer. I wonder if that's actually fire protection or if it can be used as emergency cooling?

I don't know if you Googled it, but apparently the "excited winding" is just an archaic term for the primary winding. They call the secondary the "coupled winding." :huh:

-John

 

I'm not sure, but I think they need to worry more about emergency containment than cooling. 13,000 gallon is quite a bit of oil. If it leaked even half, talk about environmental disaster.

 

Every big transformer that I've installed had a containment. Usually concrete walls 2' or 3' high.

 

That gravel in that picture is probably filling a undergound concrete basin designed with the capacity to hold the volume of one of those transformer tanks. There's either a manhole with a pump or else oil-water filters to keep the sump empty of water.

-John

 

I know where you can buy one of those bad boys if you want one:

http://www.ut-brokers.com/Home.html

They have them all the way up to 125MVA in stock!!

 

I thought the industry had switched to nontoxic mineral oils or ester based biodegradable oils for transformer cooling these days. They almost make it sound like this stuff is so environmentally safe you could put it on your morning bowl of cornflakes.

 

Indeed they do, but any transformer, after years of operation, contaminates the oil so badly it is downright nasty. And if it experiences internal arcing or burns out, the nastiness gets a lot worse.....Many years ago I got to open a failed pole-top transformer...the smell was horrible. To give you an idea, think moldy tuna, rank tennis shoes, stinky armpits, stinky foot cheese, dirty underwear, rotten eggs and burned copper...combined...and that's about 1/3 of how bad it really was. I literally lost my lunch.

 

Tertiary windings

Some transformers have a tertiary winding to supply a different voltage. Most of the ones I have seen the fan power is fed from the control house.

 

Some transformers have a tertiary winding to supply a different voltage. Most of the ones I have seen the fan power is fed from the control house.

Exactly right, you took the post out of my keyboard. (P.S. Welcome to the forum)

 

most transformer that have fins usually 75 kva and up don't have any motor in them the fins work like a radiator on a car the circulate the hot oil through the fins to cool them they're our no moving parts in a transformer.

 

Transformer Fans

The power to run these fans depends on your available station service. For example: If you have a 138 kV/13.8 kV transformer, you would place station service transformers on your 13.8 kV side. At that point, it's just like hooking up regular pole-top distribution transformers. If you need 120/240V, hook it up. If you need 120/208/240 Volts, hook it up that way. Your station service provides power for your substation, including the radiator fans. If the transformer says OA/FOA on the nameplate, use of the fans will give the transformer a higher kVA/mVA rating. Now's the time to check your fans, before the return of summer.

 

Link in my last post is broken, so here's the new link to get one of these bad boys:

New link is here: http://www.utilitytransformerbr.com/

 

Just a normal day..........:whistling2: