Panel mount ammeters

[Racinbob 11,036]

OK guys, I must be near total brain deadness. I picked up a couple of these ammeters for another little addition to my emergency power setup. Easy peasy right? Power to X1 and X2 (it shows 220v but it can be 110v as well.) CT around conductor and it's good to go. So I thunk. Both displays work fine when powered. But I'm not reading any current flow on a circuit that shows a load with my clamp-on.  Zero, zip, nada. I tried every combination of the meters and CT's. Checked the CT's and they both read good. Checked continuity through the connectors. Contemplated throwing them across the room but managed to control myself. 

 

 

 

 

Anybody used these? Come on guys, feel free to embarrass a guy with over 50 years of electrical experience. 

Edited November 28, 2021 by Racinbob

[Jeff-C175 7,199]

You don't specifically say this, but you are running the current carrying conductor through the center of the toroid, correct?  (oops, yes, you DID say that, sorry!)

 

 

And you said 'emergency power' setup, so I presume that you are NOT trying to measure DC current, also correct?

 

 

Edited November 28, 2021 by Jeff-C175

[Racinbob 11,036]

Yes Jeff. I should have been more specific. During power outages I feed the generator to the main panel through a UL listed lockout device to keep things safe and legal. I plan on mounting these next to the panel with the CT's on the two incoming lines. Yes, it's ac. 

[squonk 41,017]

 

What ever is is, it's gotta be somethin stupid! You're trying to measure off the the circuit powering the meter itself correct? 

[Jeff-C175 7,199]

13 minutes ago, Racinbob said:

Yes Jeff. I should have been more specific. During power outages I feed the generator to the main panel through a UL listed lockout device to keep things safe and legal. I plan on mounting these next to the panel with the CT's on the two incoming lines. Yes, it's ac. 

 

You were specific enough, I'm just a little foggy this morning. (what? it's not morning anymore? )

 

I'm sure you hooked 'em up correct, probably just ... well ... 'junk' from the country of China ... 

 

You know that you can 'multiply the reading by looping the wire through the core multiple times? 

 

 

Not that it's gonna help if it doesn't work at all, but how much current are you actually seeing on the Amprobe?  Maybe it's too low to register on that simple little doo-dad?

 

 

Edited November 28, 2021 by Jeff-C175

[Jeff-C175 7,199]

This is kinda funny...  "Zero Line" and "FireWire"  ...

 

But it makes me wonder... you are running the HOT through the core?  Not the Neutral?  Depending on the design, it MIGHT make a difference.

 

"Y'all needs ta put moe FAHR in yer WAHR, TAIN FOAH ?" 

 

Edited November 28, 2021 by Jeff-C175

[squonk 41,017]

Those fine little wires on those pucks. I ran into a bunch of them with the little screws the wires clamped in. After about a year inside a speed drive they worked loose. We had one where I was off site and a wire came loose on a pump drive and shut down an entire chilled water plant. Guys were running around trying to figure out why the computer showed a pump was off but the pump was running. So the Comp. thought the pump was off so it shut off the chiller and everything else. I get there and walk over to the pump drive and open it up and reinstall the little red wire.  Wah-laa! 

[Racinbob 11,036]

35 minutes ago, squonk said:

 

What ever is is, it's gotta be somethin stupid! You're trying to measure off the the circuit powering the meter itself correct? 

 

I thought about that Mike. At first I wasn't because it shouldn't matter. But I went ahead and tried it with the power feeding the display. Nothing. 

[Racinbob 11,036]

19 minutes ago, squonk said:

Those fine little wires on those pucks. I ran into a bunch of them with the little screws the wires clamped in. After about a year inside a speed drive they worked loose. We had one where I was off site and a wire came loose on a pump drive and shut down an entire chilled water plant. Guys were running around trying to figure out why the computer showed a pump was off but the pump was running. So the Comp. thought the pump was off so it shut off the chiller and everything else. I get there and walk over to the pump drive and open it up and reinstall the little red wire.  Wah-laa! 

Obviously I don't have a screw terminal to check. I did the only thing I could by ringing them out. They seem to be fine. 

[Racinbob 11,036]

42 minutes ago, Jeff-C175 said:

 

You were specific enough, I'm just a little foggy this morning. (what? it's not morning anymore? )

 

I'm sure you hooked 'em up correct, probably just ... well ... 'junk' from the country of China ... 

 

You know that you can 'multiply the reading by looping the wire through the core multiple times? 

 

 

Not that it's gonna help if it doesn't work at all, but how much current are you actually seeing on the Amprobe?  Maybe it's too low to register on that simple little doo-dad?

 

 

The ammeters are supposed to reads tenths. I had about 1.5 amps with the Amprobe clamp-on. 

[Handy Don 12,128]

29 minutes ago, squonk said:

I get there and walk over to the pump drive and open it up and reinstall the little red wire.

Fee for fixing the red wire: $. Fee for knowing which red wire to fix: $$$$$$

[Racinbob 11,036]

Just for giggles I just checked the furnace circuit. 5.5 amps. I'll go ahead and slip a CT on that circuit and see what happens. 

[Racinbob 11,036]

Problem solved. Jeff, you said it first. 1.5-2 amps just doesn't register. Funny that a 40 year old Amprobe clamp-on reads it but the new fangled crap doesn't. Once I had a CT on the furnace circuit it read it and I could even watch it ramp down as it went into the shut down sequence. At least now I know. There's another style that I'm going to try. They are SUPPOSED to read voltage, current and frequency. What the heck. It's fun playing. 

[Handy Don 12,128]

3 hours ago, Racinbob said:

Problem solved

Thanks for putting this out for us all. I learned something useful today!

[Jeff-C175 7,199]

3 hours ago, Racinbob said:

1.5-2 amps just doesn't register

 

Quote

40 year old Amprobe

 

Analog display on that one?

 

At the company I just retired from we had ammeters on the equipment we manufactured.  They were driven by microprocessors that had an ADC reading the DC shunt and passing it on to the uP to send to the display.

 

There were complaints from customers that the current display was 'jumping' around when there was zero output from the device.  

 

It was 'noise' that the ADC was picking up, from whatever... lighting, nearby motors, radio stations, whatever... 

 

The software team had to modify the firmware to cut the display off below a certain threshold.  AIRC it was about 2% of full scale.

 

I'll bet that's what's going on with those devices!  It's all about "signal to noise ratio".

 

 

Edited November 28, 2021 by Jeff-C175

[Racinbob 11,036]

14 hours ago, Jeff-C175 said:

 

 

Analog display on that one?

 

At the company I just retired from we had ammeters on the equipment we manufactured.  They were driven by microprocessors that had an ADC reading the DC shunt and passing it on to the uP to send to the display.

 

There were complaints from customers that the current display was 'jumping' around when there was zero output from the device.  

 

It was 'noise' that the ADC was picking up, from whatever... lighting, nearby motors, radio stations, whatever... 

 

The software team had to modify the firmware to cut the display off below a certain threshold.  AIRC it was about 2% of full scale.

 

I'll bet that's what's going on with those devices!  It's all about "signal to noise ratio".

 

 

 

Analog it is Jeff. Good old trusty Amprobe purchased in the 80's. I'm thinking you could drive nails with it too. 

 

 

I seriously doubt the Chinese went through the trouble with these things. They are just cheap, cheap. I'm going to get a couple more in a different style. I may not be able to them with a frequency readout because I won't buy from a seller shipping from China. Thinking about it I don't think not starting to read until 3 amps or so. That's no more than 400 watts per leg and I'm sure I'll exceed that. 

 

As we all were typing in this thread yesterday the seller replied to the message I had sent him. He really had nothing more to add but at least he responded. That's more than most do.