Adding a Amp/Volt meter to my control panel

[BitterSweetBrews]

I just bought an Amp/Volt meter for my panel. I am trying to figure out how I need to wire it in. I have wired it a few ways and none seem to work totally right.

In addition to the overall panel 240v circuit, I have separate 120v circuits on each phase for pumps and 120v RIMS. I have the pump outlets on one side and the RIMS outlet on the other. That is, I have two circuits that use one hot and the neutral to form a 120v circuit. I have separate circuits using both hots.

The problem is measuring total amperage draw for both 120v and 240v devices. I am uploading pictures of the device and its directions/schematic.



1. If I run a hot load wire through the coil it will measure 240 amperage right, but will only give me amperage for 120v on the side this hot is on. If I plug in 120v to the other side's circuit it doesn't measure it.

2. If I run both hot's through the coil it measures 120v on each side but doesn't measure 240.

3. If I run one hot and the neutral through the coil it measures differences, but it doubles up the amperage on the 120v size that the hot is from. So, it is inaccurate.

4. If I run just the Neutral through, it measures 120v loads on both circuits, but not anything 240v.

I want to get the full load for the panel for any devices running at any time. At this point, I can only figure out that I would need to re-wire all 120v to one side or the other and use that line for the measurement. I would rather not do that unless there is no other way.

Any advice would be greatly appreciated.

Thanks
Tim Trabold

 

[lschiavo]

You can only measure line to line or one line to neutral at one time. You would have to add some switching to do more. You will only be able to measure current on one hot let though with only one CT. That could work if you're only pulling 120V from one line.

 

[augiedoggy]

its really super simple... buy a second meter for your 120v circuit the meter wont do both , youll actually get some whacky readings off of it if you try from what Ive seen with mine when wired wrong.

 

[BitterSweetBrews]

Here's a follow up on what I did.

I put all of the 120v outlets on one side of the 240v and use that side to monitor everything. It seems to have done the trick and I can monitor the total controller load pretty well.

I was surprised at the readings. It sometimes says I am drawing over 30 amps on the circuit, which is probably right based on the devices, but I am not sure I believe it. My breaker wasn't tripping.

I brewed a couple days ago after installing the meter into the panel. When I ran both the 120v/1600W RIMS the 240V/5500w HLT at the same time. It says I am drawing over 30 amps when they are both cycling at 100%. It does go down once they hit temp and the cycling slows. That was pretty cool to watch. With both of them running at 100% I would expect it to draw about 36 amps. It did show around that, but never tripped my 30 amp breaker. It also never showed a total wattage of 7100 watts. If I was running one or the other alone it never showed a total wattage matching the element wattage. It showed something like 4500 watts on the 5500 watt element.

I ran a test of the circuit by running both my HLT and Boil Kettle at 240V which showed a draw of around 44 amps. Sure enough, my breaker tripped. So that's good.

Here are some pics of the controller and brew day. I made a milk stout.

I also made a grain bag for my mash tun out of a sheer poly curtain set I picked up at Walmart for $5. Boy that made cleanup a lot easier and the recirculation smooth with no hulls to block the sprinkler holes. It really augments the false bottom nicely.

There is also a pic of the 8.5 gallon fermenter, which blew its top after about 18 hours. I guess I needed a bit more headspace or a blow off tube. The airlock is filled with beer. It started out at about 1.060. I used some harvested S-04 that I started a couple days in advance.

 

[lschiavo]

Carroll O'Connor looks a bit sceptical. Maybe he's worried about the shower curtain being food safe

The meter is cool. I have one I've been meaning to add to my control panel for a while now.

 

[BitterSweetBrews]

Funny. Its a polyester sheer window curtain. I don't think i could get any flow through a shower curtain. I am sure its as food safe as a paint strainer hop bag.

 

[augiedoggy]

I just bought this one to use in a new arduino based system Im going to be building...

http://www.ebay.com/itm/192038472749?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

currently I use the one you have above in my panel. and it works the same way monitoring total load off the 240v circuit.

 

[BitterSweetBrews]

That looks like pretty much the same thing. I really like the multiple colored readouts. If the measurements are the same I might get one and swap it out.

I have been thinking of building an arduino based system too and have looked at a lot of the brew-pi threads. As cool as that would be, I am not sure I can figure out the programming aspects. It might be a bit over my head.

 

[Sparkncode]

This might explain your over the breaker rated current operation:

Breakers will allow more current than their rating for specific times.
Common types are described as B, C or D curve have different response times to different overload levels.

They will let a specific number of times their nominal current for a defined time.

I can run my 2x4500W elements on my 32A C curve breaker so 40A for a few minutes but go over 5x rated current instant trip.

The thermal part of a breaker means I can run one element at 100% power and one at 50% with the 1Hz PWM from the PID indefinitely with 40A peaks and 30A average. The average being less than the breaker rating.
Not saying its a good thing, just that breaker curves and operation allow it.


36A on a 30A breaker should eventually trip it but you could be talking hours till trip depending on the breaker type.

 

[BitterSweetBrews]

This might explain your over the breaker rated current operation:

Breakers will allow more current than their rating for specific times.
Common types are described as B, C or D curve have different response times to different overload levels.

They will let a specific number of times their nominal current for a defined time.

I can run my 2x4500W elements on my 32A C curve breaker so 40A for a few minutes but go over 5x rated current instant trip.

The thermal part of a breaker means I can run one element at 100% power and one at 50% with the 1Hz PWM from the PID indefinitely with 40A peaks and 30A average. The average being less than the breaker rating.
Not saying its a good thing, just that breaker curves and operation allow it.


36A on a 30A breaker should eventually trip it but you could be talking hours till trip depending on the breaker type.

I was thinking it may be something like that.