How does on aquire a pole pig?

[kf6pqt]

Me and this 4-1000 are just wonderin', thats all.

[W9GT]

Beware of using pole pigs out of the can/oil.  The oil not only provides for cooling, it also provides HV insulation!  Several years ago I had one that I used in the PS for my 4CX1500B amplifier that broke down after it dried out.  Quite alarming sounds and fireworks resulted.  Some pole pigs are OK, but some have inadequate insulation when dry.  As for the buzzing....sometimes they can be quieted down by tightening the bolts that hold them together.  Also.....be aware...the oil, at least in older units, contains PCBs.  Not a big deal, if you know what you are dealing with.....don't handle the stuff and put your fingers in your mouth, etc.  Probably nothing to worry about if you don't try to eat it or burn it and sniff the fumes.   Use caution!!  Some of the really old units are 2400 VAC and make ideal plate iron....the newer ones are typically 7500 VAC and might be a little high for some applications.  Although might work great with that 4-1K.  A BIG variac on the primary (orig secondary), however, will provide a useful and versatile arrangement for varying the plate volts.

Oh....I forgot to mention...one of my friends actually re-housed a pole pig in a smaller metal box (tank) and filled it with transformer oil...it worked great and was much smaller than the original can housing.

73,  Jack, W9GT

[WA1GFZ]

tree spikes, insulated gloves, come a long,

[KB5MD]

Talk with the person in charge of supplies at your local electric utility.  They can usually tell you when they are getting rid of any that are taken out of service.  

[Todd, KA1KAQ]

Hosstraders had a special on them a few years back at Hopkinton, you missed out. 

[W1RKW]

tree spikes, insulated gloves, come a long,

Chainsaw and a wrench

[WA1GFZ]

The famous white van...and the pole pig story

[John K5PRO]

Occasionally on epay. I have tried searching on "pole pig" and "pole transformer", and most of the time little model train poles come up. Search under distribution transformer. Usually a lot of dry ones show up, these are not HV like you want, they are usually 480/240/120 or such. Every once in a few months, a real pole pig shows up. One type that is in demand is a 13.8 KV primary, as it is hot for big tesla coil designs. If you find a 7500 Volt model, and run on 120 V, it would be half voltage, but have plenty of copper wire for the primary, as it would draw a slug of I. I understand that another problem of running them out of oil is the smell.

[flintstone mop]

Save your scheckels and buy a DAHL transformer.
Fred

[W1ATR]

Ok, as we know, no post is complete without me asking a couple of stupid questions, so here goes.

1. How long can a pole pig be left out of the oil for storage? The one I have in my garage was in a leaking can, so we drained, and let it dry, and I threw a big bag of desiccant, then sealed it back up. That was two years ago. My plan is to weld up the leak, find a new gasket for the top, and refill it. I picked up a couple of buckets of Shell Diala AX just for that project. I figure it would take around 9 gallons to cover the tranny.

2. How does the math work out to figure capacity? Not that I would need to try to get it there, maybe 2 amps out at best, but just for the conversation. It's a 7500v 45kVa square D unit, aluminum wound(5/8"by1/4" strap) on a strip wound core(Hypersil?)

. Just to see if I'm wrong or not, if I needed 2 amps out, would that be multiplied by the high voltage to get watts (15000W) then divide by the input voltage, (240) to get the input amperage, (62.5A)?

So, 2A*7500V=15000W/240V=62.5A??? Is this right, or at least close, or should I leave and go sweep the floor.

[Steve - WB3HUZ]

1. How long can a pole pig be left out of the oil for storage? The one I have in my garage was in a leaking can, so we drained, and let it dry, and I threw a big bag of desiccant, then sealed it back up. That was two years ago.

I think forever. The oil is for cooling.

[W1ATR]

Save your scheckels and buy a DAHL transformer.
Fred

That's an oxymoron, if I ever heard one. Save $$$ with Peter Dahl!?

Mack

I think he ment to say save ALL your money so you can give ALL of it at once it to PDahl..

[Steve - WB3HUZ]

A contradictory statement, for sure, but not an oxymoron.

oxymoron |?äks??môr?än| noun a figure of speech in which apparently contradictory terms appear in conjunction (e.g. intelligent sidebander)

Now if he said inexpensive Dahl transformer, then we'd have an oxymoron!!

Then there was the famous triple oxymoron from back in the days when Johnny Carson was the host of the Tonight Show and Jay Leno was the Permanent Guest Host.

That's an oxymoron, if I ever heard one. Save $$$ with Peter Dahl!?

[WD8BIL]

Like Gilligan's permanent glue.
It was permanent for three days !!

[W2PFY]

I would go to Poland to get one

[KB2WIG]

a few beers around closing time.......   klc

[Ed KB1HVS]

tree spikes, insulated gloves, come a long,

Chainsaw and a wrench

 And don't forget the bolt cutters.

[k4kyv]

I have used pole pigs on and off for many years.  You used to be able to pick them up from rural electric cooperatives fairly easily.  Originally, the transformer serving a house would be something like 1.5 or 3 KVA.  As people began to acquire more electrical gadgets in the home in the 50's, the smaller jobs became obsolete, to be replaced with 7.5, 10 and even higher KVA ratings.  Sometimes they would sell them at scrap iron prices.

It is probably more difficult to acquire them to-day due to the PCB scare and concern over lawsuits in case someone electrocuted himself with it.  Plus the 3 KVA's are probably long gone, and the ones being replaced today would be more like the 10 KVA range.  Those would be quite heavy, plus the inrush current to "excite" the core would pull quite a surge off the power mains.

I have never had any of mine to arc over from running them dry.  They can be noisy. I still have a couple of ones that run 3 KVA @ 7200 volts midtapped.  The oily residue left on the winding collects a lot of  dust over time.

I have found the voltage regulation of a  pole pig to be slightly inferior to that of a real plate transformer at approximately the same power rating. 

[flintstone mop]

Yup Steve, Thanks
I meant say, save ALL your money for a Peter Dahl transformer and these other things will come to pass. No more worry about overloads, arcing, is there ample current, noise, etc, etc.
Fred

[WA1HZK]

Show up at Timmies late a night with a couple of big guys.

[Carl WA1KPD]

Go to the local bowling alley or polka house. Buy one suited for your needs lots of beer and kraut
The rest is up to you..

[Tim WA1HnyLR]

pole pigs make good plate transformers. I used a 15Kva 14,400 volt unit that I connected a center tap to the voltage change switch inside the can. I punched a hole with a chassis punch for the feed through insulator for the center tap.I had to remove some of the oil to get at the switch . I soldered RG8 coass braid on to the arm of the switch. In positions 1,3,and 5 I got an even voltage leg to leg. I ultimately used position 3 which gave 5500 volts DC under load , conventional full wave rectification ,choke inpoot filter.This combination provided plenty of power for the single 4-1000 modulated by a pair of 4-1000s. Voltage regulation was good.I would never spend the money on a Peter Dahl plate transformer for a 6Kv supply for a 4-1000 rig unless it was in oil. The usual 7200 volt pole pig with a bridge rectifier looking into a choke inpoot filter should yield 6Kv or better . Just right for a 4-1000 rig. There are pole pigs that are of the single bushing type. You would have to open up the transformer to lift the side of the HV winding that is grounded to the case. Never run a pole pig out of the can.  Good luck, Tim WA1HnyLR