Re: Coil slowly getting weaker

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jared E Dwarshuis <jdwarshui@xxxxxxxxx>

NST (can) get weaker over time. Internal flash-over causes a
conductive carbon buildup. After a while you get a big resistor. I
make a Jacobs ladder out of coat hangers and test the coil when it is
new, so I can see if there is an erosion of performance over time.
(this does not harm the coil!)

I didn't invent this test, Neon sign builders have been testing NST
this way for a very long time.

You can often salvage failing NST by removing the tar and cleaning the
carbon off the secondary winding with carburettor cleaner or simmilar
solvent.

I don't think that the secondary winding even have a layer of
insulation on them. It looks like space wound bare copper. This would
explain why the carbon build up becomes a problem over time.

There must be around a mile of wire on each secondary (I am not
exagerating!). It amazes me that an NST would last 5 seconds under the
harsh conditions we impose on them.

 Sincerely: Jared Dwarshuis