Leaking Transformer

[N4TUA]

I picked up a BC-610 power supply deck for a good price at the last hamfest. The thing was a mess and basically all I want are the parts to build with. Looks like the choke and filter caps may be useable as is the plate transformer <BUT>, awh yes a but, it is leaking oil. It does work and is transforming correctly, but what a mess. I have been very careful not to get too much of this on me so far. I would like to know from the experience here if I should (1) run this with no oil, (2) try to repair leaking seams somehow? or (3) run from this as fast as I can... or maybe you have an even better idea.

TIA, Collin

[K3YA]

That doesn't look like any BC610 transformer that I've seen.  However, the printed specs look correct for a 610E or earlier transmitter.  Maybe it's a replacement part.  All the early (pre 610F) have visible cores, big end bells, and are not oil filled.  The later ones are in square cases, connections on the bottom and two 115 v primaries.

Plug the leak with solder or epoxy and use it

[KE6DF]

We moved into our current house in December 2004. It was newly built.

The transformer for ours and several other houses on our street was above ground in our front yard.

It was a box about 3' x 4' x 2'.

Anyway, things worked fine all winter, but the first really hot day, in late afternoon, there was a noise and then the power went out for the whole street.

The power company guy came a couple hours later, and swapped out the transformer.

He said he could tell the oil had drained out by looking at the site glass. What probably happened was some construction guy drove a fork lift or something into the transformer and make a small leak.

It worked fine under light load, but when a whole street worth of AC units fired up at once it blew.

So, bottom line, is if the oil level is significantly low, the transformer may work OK for light loads.

But if you run it at max ratings it may blow. Probably best to patch the leak as soon as possible while some of the oil is left.

Perhaps add some back if there is a way to do so.

[WA1GFZ]

Get yourself a 400 watt soldering iron and resolder the seam with acid flux solder. Plumbing flux should work. You want to heat the joint quickly so  you don't boil oil. Do it outside and wear a mask. That looks like a T368 transformer.

[ke7trp]

The T368 is a 6446 volt at 500ma.  So this transformer is way to small for a T3 use.

If you do not feel comfortable soldering the thing up, You can clean it and use an oil resistant sealer.  Hondabond, or permatex works.

I dont see oil at the HV insulators.  However, This is a common place for a leak. The Cork rots and fails.  You can pry out the cork, then get some O rings at napa.  Slide the O ring over the top of the insulator and it will snap down to perform a tight seal.

C

[WBear2GCR]

It looks like a soldered "fill hole" on the top... you *might* drill it or melt it (solder suck it) and see what the oil level is... unfortunately it is likely or maybe probable that it contains PCBs... you could just drain it and put the PCB oil into the Hudson River in NY to join the many many tons of it on the bottom, doubt anyone would notice? That's a humorous comment, not serious. But you could refill with modern transformer oil...  at least you could inspect the level if nothing else. I think it should not be quite up to the top, some airspace is normal...

[Opcom]

It's not really harmful if you wash your hands, don't ingest it, and don't burn it. When I encounter something like that I use rubber gloves. They remind me not to smoke or eat till the job's done.

If topping off, like to just cover the core, it might be a good idea to use a non flammable oil. PCB was added to prevent fires and explosions. Hate to see something arc and cause it to pop an insulator and  spray oil everywhere.

The EPA site has instructions for small PCB cleanups, such as from "small pcb capacitors". How to bag up the rags etc. before putting in trash. It came about from old ballasts. They have the PCB caps and are all over the place.

[The Slab Bacon]

Is it actually oil-filled, or just potted in some tarry substance that may be just leaching some of it's petroleum base out.

If it is just potted, I'd just clean it off with a solvent soaked rag and use it. If in fact, it is actually leaking oil, like others have said, solder up the leak, refill it, reseal it and let 'er rip.

[N4LTA]

PCBs are not dangerous unless ingested and them over long periods of time. The same as asbestos - way overstated by the greenies.

PCBs became common as a non flammable oil for distribution power transformers in the late 50s and 60s but were expensive and rarely used unless the power transformer was in a location indoors. Pole mounted and outdoor padmounts did not normally use it, they used mineral oil and still do. One of the problems that occurred was that the oils are compatable when mixed and when transformers went to the repair shop, often some PCB oils (trade named Askarell and Pyranol) got mixed in the storage tank very low percentages. The most common use was in capacitors that often rupture when they fail and would burst into flame with mineral oil.

The PCB oils are really not dangerous except when introduced into the enviromental food chain and cause long term exposure. They were not considered toxic at all for single exposures until the long term wildlife exposure was discovered.

Almost all of the enviromental damage was done by the manufacturing facilities that made capacitors and transformers being careless and spilling the PCBs over a long time periods. Monsanto made a mess at their capacitor facility on one of the large lakes in SC. They still advise not to eat the fish caught in one section of the lake. (I guess the fish have been told to stay in that section if they are exposed)

Pat
N4LTA

[The Slab Bacon]

If you've ever seen a pole pig blow, it can be a pretty spectacular sight. A big low-pitched boom, and a huge orange fireball!! Definately worth the watch if you can!

Our 'hood was built during / post WW2. Back when most of the houses either had 120v / 30A service or low current 220 / 50A service. As time progerssed sooner or later all of the homeowners eventually opted for "housepower" which was 220v / 100A service. The local utility companies upgraded the drop-loops into the houses but NOT the pole pigs and feeders. So seeing a pole pig blow on a 100+ degree day was not an unusual sight. They were especially kool if they went after dark! ! !

[N4TUA]

These are great facts about PCBs which I had an idea I was fairly safe except for drinking it or using it for heating oil for the furnace...
The transformer still has some oil in it and yes it is oil and it is leaking from very small cracks in the seams which appear to have been fractured somehow. Very slow leaking, actually one leak is at the seam on the bottom edge so that all of the oil is above it. This may take a bigger soldering iron than what I have (400 watt). Is the oil in there to cool the transformer? I have heard of pole pigs being used out of the oil for amateur service. Is this about the same as a pole pig, just a transformer designed for a continuous duty use?

[ke7trp]

I think alot of people make light of the situation.  I think its far more dangerous then made out to be.  The big thing is that you dont know if there is PCB in that oil unless its tested.  You can order a kit and test it.  Thats really the best way.

Some reading:

http://www.foxriverwatch.com/monsanto2a_pcb_pcbs.html


Here is the thing.  If the transmitter is in your living quarters, It should be cleaned and sealed/or removed.  If not, You have heated oil inside a hot cabinet that is pressured by air from the cooling fans. That is a perfect way to get PCB fumes all over everything in your home.  If its out in the garage or in a barn, Who really cares?  There are likely other types of chemicals there that are far worse.

I removed all my caps, Tested them and discarded them.  I replaced them with modern electrolytics and with pcb free oil.  NOT because I was worried, But because I was upgrading the transmitter anyways and why not get that crap out of there in the process? 



C

[W2VW]

All the BC-610F and up transformers I've seen use a 105 lb oil filled cube with a pair of discrete primaries. The secondary on those is 4800 or 5700 volts center tapped.

As mentioned your transformer looks like a direct replacement for the older type.

The later transformers spring leaks because wimpy people drag them around instead of picking them up. The top has lead seals. The bottom is the terminal side on the F and up models. Those are oil filled and I would not try them without it.

The BC-610 and t-368 oil filled transformers will both tolerate a full wave bridge rectifier : )

[The Slab Bacon]

I think alot of people make light of the situation.  I think its far more dangerous then made out to be.  The big thing is that you dont know if there is PCB in that oil unless its tested.  You can order a kit and test it.  Thats really the best way.
Some reading:
http://www.foxriverwatch.com/monsanto2a_pcb_pcbs.html

A very interesting read indeed................ It kinda left me thinking and doing some head scratching.

I was exposed to a lot of PCBs (and other chemicals) back in the late '70s and early '80s. I used to work for a company that did tank cleaning and oil / chemical spill cleanup. After reading that it may help explain why I have liver disease now, keeping in mind that I haven't drank in somewhere around 29 years now. I do know that your body doesn't break it down and it has a cumulative effect. Not to mention all of the contaminated foods and other stuff I / we have probably unknowingly consumed over the years.

But, also working in the automotive trade for many years I have had much exposure to all kinds of nasty stuff that makes my hepatologist kringe.

[N4LTA]

I didn't mean to indicate that PCBs are not and have not been a serious enviromental danger but it is a systemic toxin and it requires significant exposure,  as in plant workers being exposed over time, to be toxic.  It would not eat it or breath the vapors of it myself. I have in the past dipped my hands in it but would not do that now.

If the pole pigs blew up in a firey flash , they didn't have PCB oils as it takes a very hot temperature to get them to break down. When I started working in the utility industry in the 70s, pyranol and ascarel were not used in any pole mount transformers - only in special ordered transformers from GE that were deemed a fire hazard if filled with mineral oil.

I would not throw away oil filled transformers or capacitors because of a fear of PCB exposure.

I believe that the press  have tried to make the public believe that all overhead transformers were filled with PCB oil and that is not anywhere near the case. Pyranol was expensive and was not the standard oil for most utility transformers.

Pat
N4LTA

[The Slab Bacon]

PCB related stuff a few years back was a hot topic that the news media had a feeding frenzy with. But it would be interesting to know how much makes for a toxic dose, and how much we actually have accumulated in our bodies.

The PCB additive was rather expensive. (or so I've been told) and not routinely and arbitrarily used in all oil-filled electronic stuff due to it's cost. But, this raises another thought. If it was so costly, why did they just dump / dispose of it anywhere they could? ? ? ? ?

And besides, Timtron always swore that mod transformers that were oil-filled always sounded better if they had the PCB oil in them................