[Amps] meter behavior

[Fuqua, Bill L]

 I have a number of GE panel meters. They mostly have odd scales but all the movements are well damped
taught band 100uA F.S..
   I had a CAD program some years ago set up to print out new scales onto paper and cut them out
, open the meter and glue them in over the old scale. However, discovered a problem. It seemed that
after a while for some strange reason the paper scale would develop a static charge and the needle would
start sticking. 
  My tech. discovered a neat solution. He simply sprayed the new paper scale with clear krylon and the\
problem went away.
  73
Bill wa4lav

________________________________________
From: Amps [amps-bounces at contesting.com] on behalf of Dan Michnay [dfmich at comcast.net]
Sent: Wednesday, November 13, 2013 2:37 PM
To: amps at contesting.com
Subject: Re: [Amps] meter behavior

Hi there

I have several power amplifiers for the 50 through 432 MHz bands which
employ pairs of 4CX250 or similar tubes. The screens of the two tubes in
whichever amp is operational are metered separately. One has a 50-0-50
mA meter and the other has a 500-0-500 microamp meter shunted to read
steady state current like the 50-0-50 mA meter. In operation, the native
50-0-50 meter flails all over the place while the shunted meter moves at
a much more sedate pace (it's damped). I have always figured this is
because of the damping effect of the shunt on the latter meter.

So this may be one possibility for the behavior you are seeing

Cheers
73
Dan K9EA
On 11/13/2013 6:51 AM, Steve Flood wrote:
> I am trying to select some panel meters for the next amp project.  I have
> many older types to choose from in my existing stash.
>
> I have noticed over the years  that there are meters whose needles swing
> back and forth wildly while metering grid and plate currents, while others
> seem to have a dampened movement (such as the plastic Ameritron meters)
> where the needle moves more slowly.
>
> Is this due to the type of meter movement (such as d'arsonal, iron vane,
> taut band, etc.), or due to the meter sensitivity (low resistance vs high
> resistance)?
>
>
>
> I'd prefer meters with dampened needle movement, but all of my nice old
> Triplett, Weston, GE, Westinghouse, Simpson, Marion meters seem to be the
> non-dampened movement and very low resistance, and I'd rather not put
> cheapy-looking plastic meters on this project if possible.
>
>
>
> Steve KK7UV
>
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