Frank,
The one in the Wiki photo is *very* similar to the one in my scope. I
tested mine still wired in place. The line current goes through a box that
allows adjustment for different wall voltage (220/110) then through what
looks to be a transformer, then to the rheostat which is in series with the
bulb.
Charlie
On Fri, Nov 21, 2008 at 11:23 AM, Frank van Lindert <Frank@xxxxxxxxxxxxx>wrote:
> Charlie,
>
> It is a bit weird. Normally the resistance of a rheostat is zero ohms
> when the wiper is to one of the ends of the wire...
>
> Is the rheostat connected in series with the lightbulb or in series
> with the wall outlet (and the primary coil of the transformer (if
> there is any)?
>
> And did you disconnect the existing wiring when you took the
> measurement?
>
> BTW, this is exactly what the rheostat in my own contraption I
> described yesterday looks like:
> http://en.wikipedia.org/wiki/Image:Pot1.jpg
>
> Frank van Lindert
> Utrecht NL.
>
> Fri, 21 Nov 2008 09:46:38 -0500, "Charles Geilfuss"
> <charles.geilfuss@xxxxxxxxx> wrote:
>
> >Greetings,
> > Alright I have a little more infomation about my microscope rheostat:
> > Firstly to correct my bogus information, it controls a 6 volt, 20
> Watt
> >halogen bulb.
> >
> > Secondly, I removed the bottom and put a multimeter on the two leads
> >going into the body of the rheostat. I get no reading unless I set the
> >multimeter to the 200 ohm range. At the rheostat's lowest range I get a
> >reading of 0.3 and at the highest range a reading of 0.6. So if I'm using
> my
> >4th grade math correctly, the range of the rheostat is 60 ohms to 120
> ohms.
> >Do these figures make sense to those of you out there who know what you
> are
> >doing?
> >
> >Thanks,
> >Charlie
> >
> >PS Boris I have taken some photos of the part and will e-mail to you
> >off-List.
> >
> >On Wed, Nov 19, 2008 at 1:13 PM, Charles Geilfuss <
> >charles.geilfuss@xxxxxxxxx> wrote:
> >
> >> Greetings All,
> >> I know there are a few people on the List knowledgable about all
> things
> >> electrical, so I am hoping I can get some advice. I have a 15 year old
> Leitz
> >> Laborlux S microscope that I use daily. The rheostat (potentiometer)
> >> controling the light source is going bad. The light will flicker and
> does
> >> not adjust smothly in some of its range. Visual inspection of the part
> shows
> >> wear on the surface of the coil. Cleaning with De-Oxit did not help. I'm
> >> planning to replace the part but Leitz no longer carries parts for this
> >> model and my efforts to find an original part have been fruitless. There
> are
> >> plenty of potentiometers available form electrical parts companies, but
> how
> >> do I determine what specifications I need. The scope uses a 6 Watt, 20
> Volt
> >> bulb and of course plugs into a 110 Volt wall outlet. Any advice?
> >>
> >> Thanks,
> >> Charlie
> >>
> --
> _________________________________________________________________
> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
> Themed Olympus Photo Exhibition: http://www.tope.nl/
>
>
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|
