Analog Panel Meters

Fredward · February 04, 2007, 08:34:08 AM

Anybody know of a good source for Analog panel meters? 12vdc, 120vac, DCamps, ACamps? I've found them on some of the marine web sites for about $45.00 each.
I'd like to go digital but they seem to be way too expensive.
-Fred

RTS/Daytona · February 04, 2007, 09:11:03 AM

see->> http://www.allelectronics.com/cgi-bin/category/385/Meters_(Panel).html

Fredward · February 04, 2007, 10:31:04 AM

Thanks that is just what i needed.

H3Jim · February 04, 2007, 02:17:19 PM

Thanks, its a great site!

gumpy · February 04, 2007, 03:38:55 PM

OK, so someone educate me.

On the site provided above, there's a meter called, "EDGE-STYLE PANEL METER, FS=100MA".

How would one connect this into your electrical system? Obviously you can't run your power legs through that little meter. So what else do you need, and how do you hook it up? I'm thinking some sort of coil has to be installed on your incoming line? Or do you use that shunt that's shown on the same page (I was thinking this was only for DC)?

Can you run multiple meters off a single coil (or whatever the answer above is)?

DrivingMissLazy · February 04, 2007, 03:55:31 PM

Most ammeters require a separate shunt for proper operation. If you notice that instrument is labeled Labeled WATTS AT 125V. This means that you have to have a an input of 100 ma that is equal to the full scale rating stamped on the meter. Sounds like a very special meter to me.
Just below is a shunt labeled 600 AMP SHUNT, 50MV=600 AMPS. This indicates that if you have 600 amps flowing thru the shunt, there will be 50 mv across the small terminals. You need then a 50 mv meter movement that has a scale reading from 0 to 600 amps. Simple huh?
Richard

Fredward · February 04, 2007, 08:32:30 PM

Richard,
That's how I read it. It must take a little interpreting to use some of those gauges. I have requested clarification from the site. Will see what they say.
Fred

muddog16 · February 05, 2007, 03:04:46 AM

Craig most amp meters use a CT = Current Transformer. FS = Full scale 0 to 100 ma. gives you the range for which current transformer to use. The current carrying conductor passes through the CT which gives you a representative current flow safely for your Ampmeter! Always try to match your CT with your Ampmeter to get a accurate reading without having to use a factor or multiplier which will work but heck why not make it read correctly!

Pat

DrivingMissLazy · February 05, 2007, 05:53:46 AM

Pat, you are correct that for AC ammeters you can use a CT. No need to break the current carrying conductor. For DC the Shunt is typically used.
Richard

Quote from: muddog16 on February 05, 2007, 03:04:46 AM
Craig most amp meters use a CT = Current Transformer. FS = Full scale 0 to 100 ma. gives you the range for which current transformer to use. The current carrying conductor passes through the CT which gives you a representative current flow safely for your Ampmeter! Always try to match your CT with your Ampmeter to get a accurate reading without having to use a factor or multiplier which will work but heck why not make it read correctly!

Pat

gumpy · February 05, 2007, 07:04:10 AM

I knew about the shunt on DC as that's what I have on my Trimetric. But I was under the impression that you had to use a
toroid or something like that and wrap the current carrying conductor through it one or more times to inductively generate the driving current to the meter.

I know somewhere I've seen some busnut do this in his panel. It was several years ago, though, and I can't recall who it was.

I don't see anything on that site that says "current transformer". Maybe they'll send Fred some information.

That meter says Watts. It would be interesting to use Watts, but I think it would be easier to use Amps.

DrivingMissLazy · February 05, 2007, 08:25:32 AM

Quote from: gumpy on February 05, 2007, 07:04:10 AM
But I was under the impression that you had to use a
toroid or something like that and wrap the current carrying conductor through it one or more times to inductively generate the driving current to the meter.

I

That is for measuring AC current, not DC. CT's (current transformers) for AC come in a multitude of ranges and should be available at any electric supply store.
For instance a 100-5 ratio CT would give you 5 amps out when 100 amps is flowing thru the conductor passing thru the CT. The meter itself would need to be a 5 amp full scale meter movement, calibrated from 0-100 amps on the scale.
Richard