Re: Oil-immersed RFCs?

From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Sunday, August 31, 1997 4:03 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Oil-immersed RFCs?

> From:   Felix[SMTP:73374.1547-at-CompuServe.COM]
> Sent:   Friday, August 29, 1997 6:25 PM
> To:     tesla-at-pupman-dot-com
> Subject:    Oil-immersed RFCs?
> Suppose you want a pair of 5 millihenry chokes to protect neon transformers,
> The consensus seems to be that you wind them single-layer to prevent
> layer-to-layer arcing. But the solenoid equations translate this into
> things the size of a 10-gallon bucket, or alternatively a baseball bat,
> roughly speaking. Do chokes have to be that cumbersome? Why not wind
> them multi-layer and immerse in oil? I have seen corona occur within
> oil so I assume that you'd have to have enough windings to keep 
> layer-to-layer voltage below some value, based on the 50 to 60 kv 
> spikes that you're presumably trying to choke, and the corona-ing
> propensity of the high frequency components of those spikes.
> Can anyone tell me of criteria for spacing layers of windings to
> make the multi-layer, oil-immersed choke work?

I wound the 10mH chokes for my neon protection circuit multi-layer on 
bundled ferrite rod cores. Inter-layer insulation is sheet 
polyethylene. They work just fine in air.