>I’m dubious about using conducting grease for roller inductors.
.Generally, I’ve used a thin coating of dielectric silicone grease for
>that kind of application. The purpose is to lubricate the roller
>connection, to keep moisture out, and to inhibit oxidation. Under the
>pressure of the roller against the coil, there’s a good metal-to-metal
>contact.
That might be the case with a good roller inductor but in that case is
any lube needed at all? Maybe in a remote assembly outdoors.
>Using silver bearing grease as an interface between the
>roller and the inductor surface just puts a lossy, grainy material
>where it will do no good.
I do not see how grease thoroughly impregnated with silver is any
worse or lossy than silicone. The pressure that pushes silicone out
of the way will do the same thing here except that pits and voids will
have silver, hardly an insulator, in them. It mostly helps where it's
needed, which is with worn pitted inductors that normally make
intermittent contact. And since the metal particles are silver, I'd
only use it with silver plated or copper surfaces, in other words,
decent air wound coils. I should have made this obvious before but I
guess I didn't think it was necessary. My mistake.
>Conducting grease is mostly useful where one
>needs a good thermal bond, as on a CPU IC or heat sink surface.
That doesn't make it useless anywhere else, but I'll admit that having
read Rauch's comments on it, I find "dielectric" a practical misnomer
since it is oddly used where conductivity is needed. But many of
Rauch's examples involved anything and everything but the topic here,
which is roller inductors. You have to get to the end of it for that.
But once again, I am not convinced that my opinion, based on
experience, that conductive grease is a benefit for worn and pitted
wheels and coils, is incorrect.
If you want to apply so called dielectric grease to a variable
inductor in like new condition, go ahead, but that's more of a
preventive maintenance action rather than a performance improvement
action. It makes sense for ATUs at feed points but I don't believe
the original question was about inductors remoted.
73
Rob
K5UJ
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