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Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
Last year's Spring Cleaning at the local utility included getting rid of a bunch of really big old potential transformers that had lately been upgraded. Never being able to pass up the opportunity to acquire more virtually immovable transformers, I bought two of them, and transported them home in a friend's half-ton pickup truck, which almost died in the process. Here's what they look like:
They came without oil, so I re-oiled one and played with it a bit. Unfortunately, after a year, OH THE HORROR!!! I noticed oil around the base of the large bushing. Sigh... So I've made up my mind: I'm going to extricate the transformers from these cool-looking (but deterioriating) cases and find new homes for them. Should be "fun".
The essential plan is (or was) this: 1) Unbolt and remove the large bushing. 2) Reach down through the bushing hole and fit plastic drop cloth around the transformer to shield it form debris, then... 3) Grind or die cut my way around the can until the whole top half can be lifted off. 4) (if I get this far), hoist transformer out of can into temporary home (e.g., Rubbermaid(tm) plastic tub)
Well! Trouble struck as soon as I got started The flange on the bottom of the bushing looks like this:
The flange bolts were stuck tight, so I had to shear them off. Minor annoyance. After that, I discovered that what I'd believed was the top of the flange was really just a retention ring, and that the bushing flange itself was actually welded too! DAMN YOU, WESTINGHOUSE!!!
So! Now I get to grind through that too. More images soon! I can't wait to see what's been hiding inside these suckers for over 40 years. I just hope it's not a big rusty mess! From a peek through the oil spouts on the tops of the bushings, however, the insides appear to be nice and clean. At least as far down as the bottoms of the bushings. I can't see past that.
Incidentally, anybody want these big oil bushings when I'm done? The oil reservoirs should clean up nicely, although the bottom flanges will be a little messed up. Since I haven't gotten one off yet, I don't know how much they weigh, but if you can drive to my house near Seattle, they're free
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
hydraliskdragon wrote ...
Wow, thats one heak of a transformer.
What's the input volt/amp and what's the output volt/amp?
220:1 (26kV), 200kV impulse rating, 3kVA thermal/power rating. So they're HV, but not too powerful. They're PTs, after all. PTs are usually very overbuilt for their ratings, at least if you compare to pole pigs.
Should be extra nice when transplanted into smaller enclosures!
I'm supposed to be getting my angle grinder back tonight! Can't wait to start in!!
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
Well! Some surprises to report.
First, I decided to undo the main HV lead from within the oil reservoir, not knowing how it might be attached to the transformer down below. In pole pigs, the HV bushings are often not connected directly to the transformer, but to a terminal block or sockets instead. So...
Above you can see the main HV lead connecting to the top of the far side of the reservoir. After disconnecting it, here is a view down through the connection hole:
After disconnecting the lead, I set about grinding through the flange on the bottom of the bushing, which was solid copper! Imagine the cost nowadays!
When I was finally able to pull the bushing away, I was shocked to find that the transformer did, in fact, fill the whole can. It's a monster!!!
Note the beautiful woodwork!
Also, note that the core is a big E-I core with sections that unbolt!! This could really be the beginning of something interesting. But now...
...how the HELL do I get it out? I had anticipated being able to locate the LV leads from the top, but it appears I'll have to lie the thing on its side and saw part of the bottom up, too Hmmm...
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
I think I'll probably just sandblast the other one and try to patch whatever leaking may occur. Cutting this one open was a major pain, and gave me great appreciation for the cases on these things!
I never really needed two of these... and the prospect of re-potting it is rather daunting! It's got me thinking about other things I might do with it, e.g., other things I might use the core (or part of it) for, like my own homebrew transformer project or something.
I'm still trying to figure out how to approach liberating the other side of the beast from the bottom of the can.
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Pole Piglet Rescue Project
The flange on the bottom of the bushing looks like this:
This could really be the beginning of something interesting. But now...
