Although I see comments about using conductive grease, after working in
industry of over 26 years I never use conductive grease particularly for
wipers and coils on ceramic forms. The non conductive works just fine
keeping the contact areas clean. Pressure wipes the lubricant and a good
contact is made.If there is a poor contact and the grease/lube is conducting
it is likely to heat. It is far too easy to get the stuff where it doesn't
belong and once the conductive stuff is on the ceramic it normally takes
more than just wiping to remove any conductive traces. I've replaced too
insulators due to conduction due to contaminants to trust a conductive
grease. Admittedly we were running a tad more power than the amateur legal
limit though. We ran from about 6KW to over 200 KW out on some equipment.
Roger (K8RI)
> Thanks for the replies. I've got several nice edge wound roller
> inductors but never saw any of them with anything greasy on them.
> Considering how RF shows different effects than low voltage I was
> concerned. Considering there's lots I haven't been exposed to, maybe
> this was SOP nowadays. Only good way is google or ask for experience.
>
> I did remove the grease leaving the most miniscule amount behind. I
> fired it up on 10 meters and indeed the meter was solid and didn't
> fluctuate.
>
> I first did as was suggested, check out a smear under a microscope &
> didn't see anything looking like metal particulate. Of course the
> particles might be so miniscule that they don't appear to exist.
>
> Thank you all for the suggestions.
>
> 73,
>
> Gary
>
>> It would tell a lot to do a ohmeter check of some of the black goo on
>> a glass plate. Its interesting that Clint found some some conductive
>> grease that does not rely on granular particles as a slurry in the
>> grease. I haven't seen conductive grease that did not rely on the
>> slurry of particles. The black goo you have on the inductor, may be
>> something like Noalox, or Oxguard that is a slurry of metal particles
>> in an iinsulating grease carrier, and make contact when a THIN layer
>> is clamped or pressed between metal surfaces. I see your Dr prefix,
>> it would be interesting to smear a slide with the goo. You might be
>> able to see the metal particles, with a microscope. In any event
>> removal of about 90 percent of what is there would not hurt.
>>
>> All the Best, 73,
>> Pat Barthelow aa6eg@hotmail.com
>> http://www.jamesburgdish.org
>> Subscribe: http://bambi.net/jamesburg.html
>> Jamesburg Earth Station Moon Bounce Team
>>
>>
>>
>>
>> > From: w5cpt@bellsouth.net
>> > To: Gary@doctorgary.net; amps@contesting.com
>> > Date: Sun, 25 Nov 2007 16:31:28 -0600
>> > Subject: Re: [Amps] Roller inductor & wiper "grease""
>> >
>> > When I was in the military, we worked on LTV receivers that used
>> > what we called "Blue Grease". It was, obviously, blue and
>> > conductive. I even laid a short line of it on a glass plate and
>> > measured the resistance, which was remarkably low. That being said,
>> > when applying it to the inductor, the very tiniest amount was
>> > needed. Certainly not the amount in the photo. And it was only
>> > applied to the contact points of the inductor and to the hinge pin
>> > of the wiper. (the inductors were flat and wound like a Nautilus
>> > shell). My concern would be if the grease was in fact conductive and
>> > if so I would remove most of it. If it is not conductive I would
>> > remove all of it and find some that is.
>> >
>> > Clint - W5CPT
>> >
>> > ----- Original Message -----
>> > From: Gary Smith
>> > To: amps@contesting.com
>> > Sent: Sunday, November 25, 2007 4:11 PM
>> > Subject: [Amps] Roller inductor & wiper "grease""
>> >
>> >
>> > I just bought a transmatch and the capacitor was extremely loose but
>> > I figured I could repair it, it was loose enough that the weight of
>> > the rotor would cause gravity to spin it downward.
>> >
>> > I opened up the tuner and found what looked like black grease on all
>> > the friction points of the rotor. I disassembled it, found the
>> > friction clutch to govern the tension on the rotor and made all free
>> > of grease and now the capacitor works perfectly with good friction.
>> >
>> > I saw a similar grease on the inductor at the same contact points.
>> > The seller said he hadn't worked on it and the capacitor seemed to
>> > hold for him and I took him at his word and I left the stuff not
>> > wanting to backward engineer the design of the thing.
>> >
>> > Now I'm finding when tuning on 10 meters that with the tuner active,
>> > higher power causes the reflected power to jump all over the place
>> > but when running straight through & bypassing the transmatch there's
>> > no jumping of SWR at all.
>> >
>> > I was thinking when I first saw the "grease" that it was there from
>> > the beginning but now I'm thinking it was added but a previous owner
>> > to make the mechanics works more smoothly without regard to RF
>> > issues that would bring.
>> >
>> > Below is a photo of the inductor & wiper asembly. You can't miss the
>> > grease or whatever it is on the components.
>> >
>> > http://doctorgary.net/nye_inductor.jpg
>> >
>> > I am thinking I wasn't told the whole story when I bought the
>> > transmatch. So here's some questions for the group;
>> >
>> > Is the black grease you see here something that comes on some edge
>> > wound inductors?
>> >
>> > If as I suspect it is something applied by someone before me, what
>> > would be an effective way to remove this grease? I hate to have to
>> > disassemble the whole thing but will if that's the only way.
>> >
>> > I was thinking about putting rags in the bottom to keep it clean
>> > after spraying the greased parts with starting fluid which would
>> > surely degrease.
>> >
>> > Not sure what if anything should be applied to the contact surfaces
>> > after all the grease is removed. Or does this greasy stuff actually
>> > belong there?
>> >
>> > Thanks,
>> >
>> > Gary
>> > ka1j
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>
>
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