Is this transformer good for anything

[55#sofcopper]

Hey guys. I'm kinda new to the forum. I've had alot of experience with nsts but I ran across this transformer. 】 100:1 turn ratio. I believe it's a potential trans former. Anyone know if this would be good to drive a 8in tesla coil. Right now I'm using a bank of 12000v nsts equaling up to 300ma. I have four 60ma and two 30ma all in parallel.  I'm wondering what kind of current this is capable of. Is it current limited or will I need an external ballast ? Are these less fragile than nsts ? Or is it useless for a tesla coil ? Thanks for any help.

[55#sofcopper]

[55#sofcopper]

[MRMILSTAR]

That is indeed a potential transformer. They can be used to drive a SGTC but you will have to provide a method for limiting the current, typically done with an inductive ballast. Since this one appears to potted in some sort of plastic you have to careful not to overheat it.

[Mads Barnkob]

The important rating here is the Thermal rating VA/Capacity thermal at 30 degree Celsius: 1500 VA

So you have to limit the power draw to 1500 VA with current limiting as Steve mentioned.

[55#sofcopper]

So that's basically 12000v at  125ma. I'm now using a bank of nsts for 12000v at 300ma. So that's less than half the available current that I'm currently using. Are these transformers less fragile than nsts ? Sounds like I would be better off just to keep using the nsts for that coil and use the P.T. for another project. Does that sound about right ?

[MRMILSTAR]

If you are getting a reliable 12 KV at 300 ma from your NSTs I would stay with that. NSTs have built-in current limiting whereas PTs do not.

[55#sofcopper]

Just for information purposes, could it be safely pushed beyond the 125ma with some sort of forced cooling like a strong fan or submersion in oil or even possibly housing it inside a small chest type freezer. I know that's a bit unorthodox  but just a question. I imagine if it's potted it would be difficult to remove heat from the windings given all the insulation. Just a thought exercise.

[55#sofcopper]

One of my 12k 60ma nsts is actually 2  12k 60ma transformers that are Identical. Both have a secondary shorted on 1 side. I have them sanded paint off cases and stacked one on top of the other with the primary ran in parallel and phased correctly to use the good secondary from each one to get the 12kv. With the cases in contact that should share ground potential  and I should be getting the 60ma. Does this sound correct. I never tried that before and it seems to be putting out at least more than 30ma according to the arcs drawn from the two outputs in relation to the arcs drawn from each output to the case. Is this crazy ? I hasn't given me any problems. Oh and what about adding the potential trans to the bank for 425ma. Would this pose a risk to damage the nsts of the P.T. ?

[Max]

AFAIK potential transformers are overbuild to stay far away from saturation in normal operation (look at the number of digits in the ratio correction factor; then you know how far away they want to stay from non-linear regions). That means that it can handle quite a bit of abuse. The issue is, as you said, that it's basically a big chunk of iron embedded in insulation material. So you might be able to push it to twice the rated current for a few minutes easily, but then have to wait half an hour or more til the core has cooled down. Note that those values are guesstimations; no personal experience.

Kind regards,
Max

[AstRii]

I would not mess around with these transformers that much, especially not for long runs.
There is a guy on YouTube who was drawing nice arcs with couple of these and after one transformer overheated it actually exploded.

(6:20)

[Mads Barnkob]

I would not mess around with these transformers that much, especially not for long runs.
There is a guy on YouTube who was drawing nice arcs with couple of these and after one transformer overheated it actually exploded.

Breezetix is also here on HVF, though he only did post about this on Facebook, https://highvoltageforum.net/index.php?action=profile;u=1446

[breezetix]

Hey guys. I'm kinda new to the forum. I've had alot of experience with nsts but I ran across this transformer. 】 100:1 turn ratio. I believe it's a potential trans former. Anyone know if this would be good to drive a 8in tesla coil. Right now I'm using a bank of 12000v nsts equaling up to 300ma. I have four 60ma and two 30ma all in parallel.  I'm wondering what kind of current this is capable of. Is it current limited or will I need an external ballast ? Are these less fragile than nsts ? Or is it useless for a tesla coil ? Thanks for any help.

yes you can use this for your sgtc, but be careful, don't exceed the thermal VA rating like i did in the video above (i was dumb but learned my lesson). use a ballast such as a MOT, ballast it to around 1000-1500VA maximum. you may be able to run it at 2000VA or so, but only in short runs, NOT continuously. (and not every minute or so either) exceeding the VA rating can heat/burn the coils, release smoke and build up pressure. PTs have hard resin that's completely sealing the transformer itself.

You already have an nst bank, around 3600VA, why not use that instead? that's quite a lot of power.

just be careful and stay safe! you only live once.

[breezetix]

So that's basically 12000v at  125ma. I'm now using a bank of nsts for 12000v at 300ma. So that's less than half the available current that I'm currently using. Are these transformers less fragile than nsts ? Sounds like I would be better off just to keep using the nsts for that coil and use the P.T. for another project. Does that sound about right ?

I wouldn't say PTs are less fragile than NSTs.