volts/amps meter wiring question

[chewse]

After considering the +'s and -'s, I've decided to put into my 240v control panel build a combined volts and amps meter. Here is the one I purchased: http://http://www.amazon.com/dp/B00DVH64HW/ref=pe_385040_127541850_TE_item

I believe there is a thread that shows how one member wired his combined meter but I can’t seem to find the thread. Anyway, for those who do use a combined meter in their control panels, can you tell me how you wired the device? A picture would be great also. Thanks for the help.

 

[augiedoggy]

After considering the +'s and -'s, I've decided to put into my 240v control panel build a combined volts and amps meter. Here is the one I purchased: http://http://www.amazon.com/dp/B00DVH64HW/ref=pe_385040_127541850_TE_item

I believe there is a thread that shows how one member wired his combined meter but I can’t seem to find the thread. Anyway, for those who do use a combined meter in their control panels, can you tell me how you wired the device? A picture would be great also. Thanks for the help.

I bought the same one (only $9 with free shipping on ebay)
there is two inputs for each of your hot 120v leads going it for power and voltage and there is a ferrite ring with wires attached to it and wrapped around it. you want to have ONE side of the 220v circuit wires pass through the coil and it measures the draw of that voltage for the amp meter... so either L1 or L2 but not both go through the coil. the amps are measured through a magnetic field created by the coil I believe? All I know for sure is it works.

basically just like the wiring schematic on the back shows in the picture from the amazon link you shared...

 

[chewse]

So, on the 110v side of the meter, I can hook both wires up to one of the controller's coil? And then hook one of the "donut" wires to the same controller's 220v inputs? Sorry, just trying to visualize the component hookups.

 

[ajdelange]

the amps are measured through a magnetic field created by the coil I believe?

Yes, it does work by 'measuring' the magnetic field around the wire. This arrangement is called a 'current transformer' and it is similar to other transformers in that its secondary consists of a number of turns of fine wire around the torus, say 50 for purposes of illustration. The primary, in this case, consists of 1 turn (though you can increase the sensitivity by passing the load carrying wire through the doughnut more that once). Given the turns ratio if one amp flows through the primary 1/50 amp flows through the secondary and that smaller current is measured and displayed by the electronics in the meter.

The voltmeter part is like any other voltmeter. Connect its wires to the two points between which you want to see the voltage. The current portion measures the current flowing through whichever wire you poke thru the doughnut so be sure you put the wire carrying the load you are interested in through it. For example, if you are interested in knowing the current through a particular heater put one (doesn't matter which) of the wires going to that heater through it. If you are interested in knowing the current drawn by all your brewing gear then put one the the incoming phases through it. If you have asymetric (120V) loads on a biphase system it gets a little trickier as the current returning on L2 won't equal the current entering on L1 if an asymetric load is on (the difference current returns through the neutral).
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[chewse]

Yes, it does work by 'measuring' the magnetic field around the wire. This arrangement is called a 'current transformer' and it is similar to other transformers in that its secondary consists of a number of turns of fine wire around the torus, say 50 for purposes of illustration. The primary, in this case, consists of 1 turn (though you can increase the sensitivity by passing the load carrying wire through the doughnut more that once). Given the turns ratio if one amp flows through the primary 1/50 amp flows through the secondary and that smaller current is measured and displayed by the electronics in the meter.

The voltmeter part is like any other voltmeter. Connect its wires to the two points between which you want to see the voltage. The current portion measures the current flowing through whichever wire you poke thru the doughnut so be sure you put the wire carrying the load you are interested in through it. For example, if you are interested in knowing the current through a particular heater put one (doesn't matter which) of the wires going to that heater through it. If you are interested in knowing the current drawn by all your brewing gear then put one the the incoming phases through it. If you have asymetric (120V) loads on a biphase system it gets a little trickier as the current returning on L2 won't equal the current entering on L1 if an asymetric load is on (the difference current returns through the neutral).

[/QUOTE]

I think I get it. Thanks.....

 

[jeffmeh]

So if you derive all of your 120v circuits through Hot1, and Hot1 goes through the torus before terminating at any of the 240v or 120v devices, that would give an accurate reading? Thanks.

 

[The10mmKid]

That is correct Jeff.

Your key word is All of your 120V circuit wiring has to originate from the same hot lead. (All could be on L2 if that is your choice)

'da Kid

So if you derive all of your 120v circuits through Hot1, and Hot1 goes through the torus before terminating at any of the 240v or 120v devices, that would give an accurate reading? Thanks.

 

[ajdelange]

So if you derive all of your 120v circuits through Hot1, and Hot1 goes through the torus before terminating at any of the 240v or 120v devices, that would give an accurate reading? Thanks.

It will then indicate the current flowing from the source to the 120V and 240V circuits. The current going to the 240V load(s) will return through Hot2 and the current going to the 120V loads will return through the neutral. So it is an accurate reading of the sum of the currents going to the 120V and 240V circuits. Obviously to get accurate readings of the 120V load only current you would put the neutral through the torus and to read the 240V load only current you would put Hot2 through. You have a two phase setup here. For the complete picture you need one meter per phase.

 

[augiedoggy]

That is correct Jeff.

Your key word is All of your 120V circuit wiring has to originate from the same hot lead. (All could be on L2 if that is your choice)

'da Kid

This is what I did before removing my 120v circuits and going completely to DC for that stuff.

I can tell you if you make a mistake like use L1 for heating element 1 but L2 for the pumps or rims when they both are in use at the same time the amp draw will actually drop instead of climb giving you an indication that something is wrong.

 

[chewse]

Follow up questions. I have a HLT element and a RIMS Tube element. Both are 220v and each as its own contactor (40a) with 120v coil. My plan is to start the sparge water in the HLT before the RIMS recirculation is complete; so both elements will be firing at the same time. I have enough amps to cover both at the same time.

In order to get a complete reading, would I connect both 120v coils (hot and neutral) to the volts/amps meter with only one, say the HLT SSR hot, going through the donut?

 

[The10mmKid]

Chew,
Can you post a pic of your panel?
I can then point to the best location for the CT.

'da Kid

Follow up questions. I have a HLT element and a RIMS Tube element. Both are 220v and each as its own contactor (40a) with 120v coil. My plan is to start the sparge water in the HLT before the RIMS recirculation is complete; so both elements will be firing at the same time. I have enough amps to cover both at the same time.

In order to get a complete reading, would I connect both 120v coils (hot and neutral) to the volts/amps meter with only one, say the HLT SSR hot, going through the donut?

 

[augiedoggy]

Follow up questions. I have a HLT element and a RIMS Tube element. Both are 220v and each as its own contactor (40a) with 120v coil. My plan is to start the sparge water in the HLT before the RIMS recirculation is complete; so both elements will be firing at the same time. I have enough amps to cover both at the same time.

In order to get a complete reading, would I connect both 120v coils (hot and neutral) to the volts/amps meter with only one, say the HLT SSR hot, going through the donut?

honestly you can skip running the coil power through the cntactors if you really want since they draw so little ampload that it wont matter... just keep the back of your mind that theres a 1/2 amp? greater load being used than the meter states... or put the amp meter coil at the point were your main power meets your terminal block and catch everything running off that leg 240 or 120v...

 

[chewse]

Chew,
Can you post a pic of your panel?
I can then point to the best location for the CT.

'da Kid

I'm still in the process of building the panel. However, I'm using the Electric Brewing Supply 50a schematic. I attached the schematic PDF file.

So, where would best place to draw the 110v and 220v volts/amps based on the schematic?

View attachment 50a PID 2-element Complete.pdf

 

[ajdelange]

I can tell you if you make a mistake like use L1 for heating element 1 but L2 for the pumps or rims when they both are in use at the same time the amp draw will actually drop instead of climb giving you an indication that something is wrong.

Don't think so. Picture a source at the left side of the page and loads on the right. Freeze time when the AC voltage is at its peak. Then you have a red wire (L1) at +120V (its actually higher than that instantaneously but let's keep it simple), a white wire at 0 volts (N) and a black wire (L2) at -120 volts. Any 240 V load is connected between L1 and L2 and the current circulates in a clockwise direction from red, through the load, through black and back to the source at the left. That current we can call I1. If there are no 120 volt loads connected to L1 then I1 is the total current in the red wire. A CT on the red wire with its arrow pointed to the right will measure +I1. A CT on the black wire will with its arrow pointed to the right measure -I1 and one on the neutral will read 0. If you now connect a 120V load between black and neutral current will flow from the neutral (it is positive relative to L2), through that load and back to the source (clockwise in the diagram) through the black wire. Call that current I2. The current in the red wire is unchanged but the current in the black wire is now the sum of I1 and I2 and the CT on the black wire thus measures -(I1 + I2). A CT on the neutral (arrow to the right) now measures +I2.

 

[ajdelange]

Follow up questions. I have a HLT element and a RIMS Tube element. Both are 220v and each as its own contactor (40a) with 120v coil. My plan is to start the sparge water in the HLT before the RIMS recirculation is complete; so both elements will be firing at the same time. I have enough amps to cover both at the same time.

In order to get a complete reading, would I connect both 120v coils (hot and neutral) to the volts/amps meter with only one, say the HLT SSR hot, going through the donut?

It depends on what voltage and what current you want to measure. Presumably the voltage would be the supply voltage in which case you connect the voltage leads to the system line inputs (L1 and L2). That makes most sense (to me anyway). If you want to measure the total load drawn by both the heaters and not the other stuff (controls, pumps, etc.) then you can just run the two SSR output wires through the doughnut, if that's convenient* or you can run the common wire which feeds the supply side of the two SSRs through the doughnut. If you want the total system load then you would, for a completely accurate picture, need two meters, one on L1 and one on L2.

*If you run both SSR to heater wires be sure they are phased properly. If both derive from L1 or both derive from L2 then be sure the SSRs are on the same side of the torus. If, for some reason, one derives from L1 and the other from L2 run the wires through the doughnut it opposite directions. If, given that one load is on, the other comes on and the indicated current increases you have it right (and conversely).

 

[ajdelange]

So, where would best place to draw the 110v and 220v volts/amps based on the schematic?

Does this mean you wish to monitor the 110 and 220V loads separately? In that case connect the voltage leads from the first meter between the inputs of the terminal blocks labeled, respectively, 110V leg 1 and 110V leg2. Pass the wire going to the input of the 110V leg1 block through the doughnut of this meter. This meter will read the sum of the heater currents.

Connect the voltage leads of the other meter between the 110v leg2 terminal block and the 'common' terminal block. Pass the neutral wire (from the GFCI to the 'common' terminal block through the doughnut of this meter. This meter will read the sum of the low voltage current draws (no heater current).

As I often do in cases like this, I feel compelled to comment that the questions indicate little or no understanding of electric fundamentals and in such cases I often question, with respect, whether you should be fiddling with this stuff. I at least can strongly suggest that you seek the assistance of someone who is knowledgeable in such things before you hurt yourself or damage your equipment.

 

[chewse]

Does this mean you wish to monitor the 110 and 220V loads separately? In that case connect the voltage leads from the first meter between the inputs of the terminal blocks labeled, respectively, 110V leg 1 and 110V leg2. Pass the wire going to the input of the 110V leg1 block through the doughnut of this meter. This meter will read the sum of the heater currents.

Connect the voltage leads of the other meter between the 110v leg2 terminal block and the 'common' terminal block. Pass the neutral wire (from the GFCI to the 'common' terminal block through the doughnut of this meter. This meter will read the sum of the low voltage current draws (no heater current).

As I often do in cases like this, I feel compelled to comment that the questions indicate little or no understanding of electric fundamentals and in such cases I often question, with respect, whether you should be fiddling with this stuff. I at least can strongly suggest that you seek the assistance of someone who is knowledgeable in such things before you hurt yourself or damage your equipment.

Thank you. The 110v really was just to power the volts/amps meter itself. The control panel is 220v. I want the volts/amps meter to monitor the volts and the amps when the control panel is in full use; i.e., when the HLT and RIMS heaters are both firing.

You are correct, I am not an electrician but am very good at figuring out things and following examples. Unfortunately, I have not seen any information on the forum that clearly shows the wiring required to monitor the complete control panel using one volts/amps meter.

Thanks again for your help.

 

[ajdelange]

The 110v really was just to power the volts/amps meter itself.

I assumed the meter would be powered from its voltage sense connections. If it has to be powered separately with 110 then connect those power leads to the 110v Leg 2 block and the common block. Then connect the voltage sense leads to whatever you want to measure which, as...

The control panel is 220v.

... I assume is 220 V.

I want the volts/amps meter to monitor the volts and the amps when the control panel is in full use; i.e., when the HLT and RIMS heaters are both firing.

It still isn't clear to me whether you want to monitor total panel current consumption or just that of the heaters. To monitor just the heaters put the wire from the main contactor to the 110v Leg A terminal block through the torus. To monitor heaters and 120V loads put the wire from the contactor to the 110v Leg 2 terminal block through the torus. Recognize that if you do this the displayed current will be the sum of the pump and control circuit currents added to the heater current.

 

[augiedoggy]

Don't think so. Picture a source at the left side of the page and loads on the right. Freeze time when the AC voltage is at its peak. Then you have a red wire (L1) at +120V (its actually higher than that instantaneously but let's keep it simple), a white wire at 0 volts (N) and a black wire (L2) at -120 volts. Any 240 V load is connected between L1 and L2 and the current circulates in a clockwise direction from red, through the load, through black and back to the source at the left. That current we can call I1. If there are no 120 volt loads connected to L1 then I1 is the total current in the red wire. A CT on the red wire with its arrow pointed to the right will measure +I1. A CT on the black wire will with its arrow pointed to the right measure -I1 and one on the neutral will read 0. If you now connect a 120V load between black and neutral current will flow from the neutral (it is positive relative to L2), through that load and back to the source (clockwise in the diagram) through the black wire. Call that current I2. The current in the red wire is unchanged but the current in the black wire is now the sum of I1 and I2 and the CT on the black wire thus measures -(I1 + I2). A CT on the neutral (arrow to the right) now measures +I2.

I only made this statement because Thats exactly what I did recently... I swapped the hot leads going to my rims tube accidently while rewiring a new wire gland on my control panel.... now when ever the rims comes on by iself it measures the correct 3.9-4 amp draw and when say one of my 4500w elements comes on I get an 18 amp draw but when the two come on at the same time I get close to a 14 amp draw untill the rims kiscks off then it goes back up

 

[augiedoggy]

Thank you. The 110v really was just to power the volts/amps meter itself. The control panel is 220v. I want the volts/amps meter to monitor the volts and the amps when the control panel is in full use; i.e., when the HLT and RIMS heaters are both firing.

You are correct, I am not an electrician but am very good at figuring out things and following examples. Unfortunately, I have not seen any information on the forum that clearly shows the wiring required to monitor the complete control panel using one volts/amps meter.

Thanks again for your help.

but the amp meter you linked runs on 110 or 220v? why power it off 110v? it will only read the 110 voltage if you do it that way... it has to be powered off the same voltage its displaying. Dont you still need 110v for the contactor coils right?
220v (which is actually close to 240v) is made up of 2 110-120v legs of power ... then you need a nuetral for proper 120v devices like your coil to operate... so to power your 110v coil you use 1 hot leg not both and you want that same leg to go through the taurus ring so ALL the amp current in your panel is measured...

 

[chewse]

but the amp meter you linked runs on 110 or 220v? why power it off 110v? it will only read the 110 voltage if you do it that way... it has to be powered off the same voltage its displaying. Dont you still need 110v for the contactor coils right?
220v (which is actually close to 240v) is made up of 2 110-120v legs of power ... then you need a nuetral for proper 120v devices like your coil to operate... so to power your 110v coil you use 1 hot leg not both and you want that same leg to go through the taurus ring so ALL the amp current in your panel is measured...

That makes sense! Thanks for the advise!

 

[ajdelange]

I only made this statement because Thats exactly what I did recently... I swapped the hot leads going to my rims tube accidently while rewiring a new wire gland on my control panel.... now when ever the rims comes on by iself it measures the correct 3.9-4 amp draw and when say one of my 4500w elements comes on I get an 18 amp draw but when the two come on at the same time I get close to a 14 amp draw untill the rims kiscks off then it goes back up

The only way this could happen (that I can think of quickly) is if:
1) Both the main heater and the rims heater are 120V devices and connected to opposite phases and...
2) You are measuring the current in the neutral.

If both loads are connected to the same phase then the current in the neutral sums. If they are connected to opposite phases the currents in the neutral subtract from one another. Ideally the loads connected to L1 and L2 are matched so the neutral current is 0.

I can't tell from your wording whether this is what you did or not but the circuit laws are pretty immutable. I have never seen them violated. Perhaps I'm not understanding what you did but I can't draw a circuit in which adding a load causes a reduction in the current in either of the phases. If there's a way to do that let me know and I'll reconfigure my electric meter as they charge for the sum of the currents drawn by the two legs (each multiplied by the phase to neutral voltage).

 

[augiedoggy]

The only way this could happen (that I can think of quickly) is if:
1) Both the main heater and the rims heater are 120V devices and connected to opposite phases and...
2) You are measuring the current in the neutral.

If both loads are connected to the same phase then the current in the neutral sums. If they are connected to opposite phases the currents in the neutral subtract from one another. Ideally the loads connected to L1 and L2 are matched so the neutral current is 0.

I can't tell from your wording whether this is what you did or not but the circuit laws are pretty immutable. I have never seen them violated. Perhaps I'm not understanding what you did but I can't draw a circuit in which adding a load causes a reduction in the current in either of the phases. If there's a way to do that let me know and I'll reconfigure my electric meter as they charge for the sum of the currents drawn by the two legs (each multiplied by the phase to neutral voltage).

What your saying makes sense to me..I really didnt think it through.. . I am waiting on a flow switch to arrive and I will be tearing into my panel again to wire up the flow switch to kill my rims element if flow stops so I will double check it and see whats wrong then.

 

[The10mmKid]

Hey Chew,
Looking at pg #1 on the print.
For total panel draw; I'd place the CT coil with the Grey 6ga wire passing through it. It doesn't matter if it's before or after the two-pole contactor. (current is constant in a series circuit).

'da Kid

I'm still in the process of building the panel. However, I'm using the Electric Brewing Supply 50a schematic. I attached the schematic PDF file.

So, where would best place to draw the 110v and 220v volts/amps based on the schematic?

 

[Wynne-R]

That would be something if we could violate Joule’s 1st Law. Instead of screwing around with 80 or 90% efficiency it would be fun to get into the 100's.

Rewriting physics as we know it, the last thing you’d have to worry about is your electricity bill. So, AJ, how are you going to spend your Nobel prize?

I think AJ’s right about the neutral. Obviously some sort of measurement error.

Chewse, are you good and confused yet?

 

[chewse]

Hey Chew,
Looking at pg #1 on the print.
For total panel draw; I'd place the CT coil with the Grey 6ga wire passing through it. It doesn't matter if it's before or after the two-pole contactor. (current is constant in a series circuit).

'da Kid

Thank you!

 

[augiedoggy]

The only way this could happen (that I can think of quickly) is if:
1) Both the main heater and the rims heater are 120V devices and connected to opposite phases and...
2) You are measuring the current in the neutral.

If both loads are connected to the same phase then the current in the neutral sums. If they are connected to opposite phases the currents in the neutral subtract from one another. Ideally the loads connected to L1 and L2 are matched so the neutral current is 0.

I can't tell from your wording whether this is what you did or not but the circuit laws are pretty immutable. I have never seen them violated. Perhaps I'm not understanding what you did but I can't draw a circuit in which adding a load causes a reduction in the current in either of the phases. If there's a way to do that let me know and I'll reconfigure my electric meter as they charge for the sum of the currents drawn by the two legs (each multiplied by the phase to neutral voltage).

OK Update<
I verified the wiring in my panel and saw that my original assumption was correct.
I just swapped the #2 hot with the #1 hot (which my other two elements also use for the torus and my amps draw are now reading correctly with wither on or both at the same time.
So laws of physics aside My original assumptions were correct regardless.... The ground goes no where near the torus. Perhaps some of these meters dont work exactly the way you guys would think and reversed fields have an effect of negating some of the the measured field of the opposite field? It actually makes sense to me, it only measured wrong when both elements were being fired at once so the fact that some of that current was being "Measured both ways" inside the torus when returning through the opposite line this would cause the fiels measured to be effected. for the same reason the volt meter would not work with both wires of the circiut passing through as one would negate the field of the other right? since the hot lines in an 240v circuit found in the US are in fact acting as each others "return" lines of whatever the correct terminology is here.

I went as far as to pulling the wiring apart in my element (I would have electrocuted myself if it was really wrong since I have the ground going to the rims tube body) and checked my wiring there with a meter. there is absolutely no doubt that it was just a matter of the my two hots being crossed on the rims line for the torus.

BTW I do not have a neutral running into my panel..only two hots and a ground.

 

[augiedoggy]

That would be something if we could violate Joule&#8217;s 1st Law. Instead of screwing around with 80 or 90% efficiency it would be fun to get into the 100's.

Rewriting physics as we know it, the last thing you&#8217;d have to worry about is your electricity bill. So, AJ, how are you going to spend your Nobel prize?

I think AJ&#8217;s right about the neutral. Obviously some sort of measurement error.

Chewse, are you good and confused yet?

See my post above ... No nobel prize needed , Cocky comments aside its not a measurement error.