Log in

View Full Version : So I got my hands on a Light Pole Transformer :)


emag
2008-09-10, 23:57
*
Anyone familiar with taking and converting these for lab/shop use? Gustav blew it down and the power company left it after putting up a new one. It's not leaking or anything but I'm worried about the coolant stuff in it because I'm wanting to open it up and take the actual transformer out to save space and weight. Supposedly it can be some really nasty stuff (http://en.wikipedia.org/wiki/Polychlorinated_biphenyl), health-wise.
How might I find out what's in it and, depending on what it is, go about disposing of it?

Can anyone give me any advice, warnings, tips, experiences, or any information about these things that I should know?

I was going to use it for stepping 120V down for some low voltage-high current applications like to maybe make a welder or an induction heater or something. Any ideas would be appreciated.


*Mods, I didn't know whether this should go in MS, T&T, LT, here or some other forum; please move to wherever you think it'll be better answered.

ArgonPlasma2000
2008-09-11, 02:08
Induction heaters need high frequency, and those transformers wont take it.

Leave the transformer intact. The reason PCB oils are used is because they have very high dielectric ratings.

emag
2008-09-11, 16:41
Shit, I misread the wiki page (http://en.wikipedia.org/wiki/Induction_heating#Details) as Hz instead of kHz.
What about the transformer would make it not able to take it?

Do EE undergrads learn about designing transformers like these? Do yall take some basic heat transfer courses for applications such as this? I'm trying to figure out who I should go and ask about this kinda stuff.

ArgonPlasma2000
2008-09-11, 16:48
We do thermodynamics at my university, but it's stuff like steam turbines and whatnot. We also don't go into physically designing a transformer. Hell, we don't talk much about the real world much at all. (A PhD at the lab I work at who also graduated from this uni was commenting on this one day) We do talk about why the input to output sees negligible inductance from one side to the other.

We also don't talk about why eddies form in magnetic media when under high frequency magnetic fields. Hell, I doubt there are more than a couple who could tell me what an eddy even is.

Runaway_Stapler
2008-09-12, 00:20
We also don't talk about why eddies form in magnetic media when under high frequency magnetic fields. Hell, I doubt there are more than a couple who could tell me what an eddy even is.

I'll take a stab at it! Is it small wave-like variations in the media, like water looks when a breeze is blowing across the surface?

ArgonPlasma2000
2008-09-12, 02:28
I'll take a stab at it! Is it small wave-like variations in the media, like water looks when a breeze is blowing across the surface?

An eddy is nothing but a closed path of current. Of course, if the wind blew hard enough, it might form some eddies.

grusomhat
2008-09-12, 13:36
An eddy is nothing but a closed path of current. Of course, if the wind blew hard enough, it might form some eddies.

Similar to an eddy in a river no? Water runs down stream, hits a rock, runs back up and repeats as the water running upstream behind rock, goes back into the main stream.

eesakiwi
2008-09-13, 09:07
A eddy is a moving magnetic feild caused by electricity.

Sorta like if you got a magnet & vibrated it.

Its the movement of the magnet inside a magnetic feild that makes electrons move in the wire. Which is the oppisite of the first paragraph.

Moving a magnetic field makes electricity.
Electricity makes a moving magnetic field.

Endotropic Decay
2008-09-13, 20:02
So much talk about eddies.

I think I'll just jump in and ask a question...

what/how are they caused in a coilgun, and why are they bad?

from the little I've read about them, I'd assume it would be the magnetic field inducing a current in another magnetic part of the coil gun (that isn't the projectile) and that wasting some of the energy as heat, since the part can't move...

Or am I completely wrong...?

I did just kind of guess...

ArgonPlasma2000
2008-09-14, 03:56
So much talk about eddies.

I think I'll just jump in and ask a question...

what/how are they caused in a coilgun, and why are they bad?

from the little I've read about them, I'd assume it would be the magnetic field inducing a current in another magnetic part of the coil gun (that isn't the projectile) and that wasting some of the energy as heat, since the part can't move...

Or am I completely wrong...?

I did just kind of guess...

http://en.wikipedia.org/wiki/Eddy_current

emag
2008-09-14, 06:54
Well, it turns out almost every drop of oil that was in the transformer had actually leaked out when it fell. I've done a little searching and I'm really thinking it likely didn't have PCB oils in it anyways. The label has no date only says "oil" and I think PCB oil containing transformers are supposed to be labeled as so.

ArgonPlasma2000
2008-09-15, 01:05
Well, it turns out almost every drop of oil that was in the transformer had actually leaked out when it fell. I've done a little searching and I'm really thinking it likely didn't have PCB oils in it anyways. The label has no date only says "oil" and I think PCB oil containing transformers are supposed to be labeled as so.

You are probably right. It should say it is an environmental hazard or something if its got PCBs in it.

There are some shops that sell transformer oil. I'd recommend using something, even virgin synthetic motor oil, if you are going to do anything heavy duty with it. The oil is not only there to provide a dielectric, but also to cool the windings.

Also, I forgot to put this in the other post about the eddies. Here is why eddies in a coilgun are bad: http://www.youtube.com/watch?v=WHCwgc_xs3s&feature=related

eesakiwi
2008-09-15, 08:51
I have pulled the capactors in a microwave apart before & also car coils.
The microwave caps had a smelly oil in them, it smelt just like insect repellant, the DEET sort.
Wouldn't be suprised if it was...

The coils just had a thin oil in them, poured it into the rubbish bin.

I think the dangerous oil was called 'PCB' for short. Yeah it could be bad for you, but I know that people used to work daily with it for years.
A one time, short term exposure isn't gonna kill you.

I can't think of anything to do with the tranny except cut the copper wire out of it & save up enough to take it to a scrapmetal dealer.
Its not gonna have as much as 1Kg of copper, which makes it worth less than US$5.
Sorry.

ArgonPlasma2000
2008-09-16, 04:20
I have pulled the capactors in a microwave apart before & also car coils.
The microwave caps had a smelly oil in them, it smelt just like insect repellant, the DEET sort.
Wouldn't be suprised if it was...

I wouldn't doubt it. The case makes a good place for insects to dwell, and living matter generally doesn't take too well to high voltage.

Chainhit
2008-09-16, 21:37
I would not be confident that it does not have any pcbs in it without lab tests on a GC
(tests for chlorine in oil)

a member of my family works for a lab that does all these tests (for coned). While these things are supposed to be labeled and whatnot, alot of the records are shoddy, or in many cases no record exists of PCB's. For instance, a transformer (big room sized ) caught on fire, and it was checked out to be clear by power company, turned out to have some small compartment with PCB's in it that ruptured from the fire.

Id approach it on the side of caution, pcbs are not that dangerous to your health (more of a environmental hazard), but you never know, especially with an old transformer.

emag
2008-09-16, 23:19
Thanks for that info, Chainhit.

I tried looking for a datasheet or some info from the company on the label on it** but the company seems to have changed since the transformer was made and I don't have any idea how long that could have been, I couldn't find any dates on anything. The new company does say that they use non-pcb oils, but that certainly doesn't mean they didn't use to.


**Can someone please remind me what the heck the term is for the little aluminum plate on stuff like large AC motors and stuff that has the model & serial numbers and power ratings & stuff?

ArgonPlasma2000
2008-09-17, 05:53
I just call them specification tags.