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Re: Bad NST



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Rich,

Hopefully the core is an EI type so you can easily add a gap. If the E and I laminents are interleaved, a cut will be required. BTW, I wrote a "gapped toroid" ballast design program that I could easily modify for EI ballast design and will be happy to run some numbers thru if you tell me how it compares to "reality". Im currently building a gapped toroid ballast based on this program and once my blisters heal from working with 8awg, I will get a sanity cheak as well. :o))

Gerry R.


Original poster: "Rich" <rdjmgmt@xxxxxxxxxx>

Hi Gerry, I have removed the tar, nicked one secondary and had to remove
a few windings, the other side is bad and had to remove about 1/3 of the
windings to get continuity and then the side with the most wire removed
has the highest resistance reading. So I know it would not hold up for
TC use. People talk about a roll of 12ga wire with steel rods in the
center for a inductive ballast so I thought I would try the 10ga primary
from the NST.
FYI, The Jefferson does not have "normal" shunts I can remove. I guess I
could cut a slot in them.

Rich

Subject: Re: Bad NST

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Rich,

In general, I think you could reuse the core for a lot of purposes
including a ballast.  In this case, some calculations will be needed
to make sure the core is big enough and wont saturate.  Before you
tear down the NST, you might try to melt the tar in the oven and
maybe fix the problem.

Gerry R.

>Original poster: "Rich" <rdjmgmt@xxxxxxxxxx>
>
>OK, I give up I have a bad Jefferson 15kv60ma NST. One secondary is
>bad, the other is questionable. My question is, I still have a good
>chunk of iron and a solid 10ga primary, and can I remove the
>secondarys and use the primary as part of ballast for a standard
>transformer. I know the standard way is to short the secondarys to
>use a transformer but wont it still give me some inductance?  I have
>a coil I am building that will require 240v 9amp and was thinking
>about a inductive / restive ballast.
>
>Rich
>
>