Re: oil dielectric

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

> I use oil in one of my secondaries.  There is absolutely no

> heating.  Even if there were, the plastic pipe the coil is

> wound on is more likely to burn than the transformer oil.

> The oil actually keeps the coil cool by damping molecular

> movement.


	Having done some thermal design & studied transformer
	design, I'd find that surprising.  Oil, in a conventional
	transformer functions in two ways:
		Electrical Insulation
		Thermal
	The thermal effect is by being heated by hot spots
	(core eddy currents, coil resistance losses), then flowing,
	by natural convection, or, less commonly, pumped
	circulation, to a cooler spot where it can dump heat.
	Sometimes the cool spot is aided by heat sinks ('fins').
  	cf any text on transformer design.

> The way I wound the coil was to wind it on a 3.5" OD
> PVC pipe and then slide a 4.5" OD PVC pipe over it and seal

	This makes me nervous.

> both ends.  I left a quarter inch hole in the top plug and used

> something like a turkey baster to fill the coil with oil. When I

> was done, I sealed the small hole.

	I say nervous because a sealed container, can, if heated,
	even by a fault, 'rapidly disassemble':  Explode.
	Unlikely, probably, here, but possible.  (Power
	transformers can and have exploded, when not vented.)

 
> I like this coil so much I'm going to wind another one.  This time

>I'll use finer wire if I can get some.

	In general, fine wire increases losses, limiting power,
	and increases heating...

	best
	dwp