Re: Panel Meter Question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

Mine look "fairly" new:

http://www.hot-streamer.com/adam/bigass_coil/meters.jpg

But I suspect you're probably right about the
accuracy. I had a VTVM and a VOM that were very
accurate (at least I thought they were), but these
were probably mass produced. It runs smoothly without
any sticking, though I have to wonder what caused the
resistor to blow up before I bought it! Actually, when
I was testing it with a JL on my pig, once the arc
started, I read nearly zero, so I'm not sure whether
it's gonna tell me anything with a running coil
anyway.

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Terry Fritz
> <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi Adam,
>
> Most analog panel meters that are older are just not
> real good in
> these days of 0.001% DVMs.  The "best" were 5% with
> most good ones in
> the 10% range.  Normal ones could be out to 20%...
> I would find the
> most important voltage point for your application
> and set it to read
> that point well and be happy ;-))
>
> Some of the very old "laboratory" type meters that
> claimed high
> accuracy also do not stand up well to modern voltage
> standards.  Back
> then, nobody would know if they really were "off"
> ;-))  They can be
> affected but the direction of North and if they are
> upright of laying
> flat too.  You might want to be sure that the
> pointer is set right on
> zero and run them back and forth many times just to
> drive out tiny
> dust from the moving parts.
>
> Modern analog meters can hit 2% full scale, 2%
> repeatability, and 3%
> "tracking" thanks to computer modeling and some
> fancy tricks.  They
> also cost about $100 each!!
>
> If the meter works well without sticky spots or
> other obvious bad
> problems, consider them "just fine"!
>
> Cheers,
>
>          Terry
>
>
> At 07:50 PM 10/1/2005, you wrote:
> >I have a Weston 7544 panel meter that I bought
> used.
> >It that reads from 0 to 300 VAC. It came with two
> 22k
> >resistors in series with one of the leads, located
> in
> >a small compartment. One of them is blown. The
> other
> >reads 22.36k on my Fluke DMM. I went to my resistor
> >drawer and found one that also reads 22.36k. When I
> >place it in series with the good resistor, the
> meter
> >reads too low across the scale. At 100VAC, it reads
> >90, and at 279 it reads 273. So I hooked it
> straight
> >up to a variac without any resistors, and measured
> the
> >input voltage and meter readings from 100 to 300. I
> >figured I could simply find the ratio and calculate
> a
> >better fit for a resistor. The problem is that it's
> >not linear. It ranges from 21.86 volts input to
> read
> >100 volts, up to 59.1 volts to read 300 volts. I
> >created a spreadsheet and played around a bit. If I
> >pick a resistor value to make 300 volts correct,
> I'm
> >10 volts too low at 100. If I correct at 100, I'm
> 35
> >volts too high at 300. Is there a better way to do
> >this, or should I pick an average value, and call
> it
> >close enough?
> >
> >thanks
> >Adam
>
>
>



		
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