You need to go through the calibration process and adjust the code to get the correct current reading and this will carry through to your kWh recordings as well. Hi, my name is Michael and I started this blog in 2016 to share my DIY journey with you. This should be around 500-5000 to 1. To calculate how many amps yours needs to sense, take the maximum continuous power your are expecting to sense and divide that by your voltage (usually 110V or 220V depending on your country). This article worked on 42A with. Very interesting post!, I need to monitor hourly consumptions on a 3 phase grid over a few months. To calibrate your energy meter, your need to be sure that the current that your meter says is being drawn on each phase is what you expect is actually being drawn. But the readings of current I got r much more higher than the actual current value. Here are some options on different CTs and their ideal burden resistors (in standard sizes): The capacitor used is 10F which should be sufficient for most CT ranges for household applications.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'the_diy_life_com-banner-1','ezslot_10',175,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-the_diy_life_com-banner-1-0')}; Finally you need two dividing resistors to get the 2.5V reference voltage from the Arduino.

very thanks for this project. maxCurrent = 516; <- same here I would like to connect all the -ve sides together and tie those to ground. can somebody please explain how the working of above circuit diagram (ct, resistors,capacitors)?thanks. If you're looking for some different projects with step by step guides and code, have a look at these Arduino base projects which I've written. Zd sa, e existuje problm s prekladom, nie som si celkom ist, o sa pokate opta. If you connect them directly to the Arudino inputs then youll have a voltage input onto the Arduinos analogue inputs which fluctuates positive and negative and you dont want to be putting a negative voltage onto the Arduinos inputs, it doesnt handle this well. An perhaps test the voltage on the analogue input and check that it continues to increase when the input current goes beyond 16.91 amps. The closest standard resistor value is 56, so this was used. Do not remove any wires or remove any screws before checking your local regulations with your local authority, you may require a certified electrician to install the CT for you.

To calibrate your energy meter, your need to be sure that the current that your meter says is being drawn on each phase is what you expect is actually being drawn. How can we attach ZMPT to sense voltages then use them while meausring the energy? They must be the same value, so R1=R2 and we dont need much current so this articles uses two 100K resistors. Or should the other values also be changed accordingly. Setting the Arduino analog reference to INTERNAL, means that it uses the internal 1.1V as its ADC vRef a handy hint I got from @jonoxer once upon a time. Yes, we connect it to the high side of the voltage divider so that the current sine waves midpoint is elevated to 2.5V. Next you need to size your burden resistor R3, this converts your CT current into a voltage reference. Your analogue reference voltage to the Arduino is 2.5V so to determine the resistance you use R=V/I R=2.5/0.042=59.5. Yes, you'd simply remove one of the CTs and one of the sections of the code. 2 years ago. You can email the code and any photos you have through to admin(at)the-diy-life.com and well have a look at posting your project, with credit to you of course. Putting the CT onlu on neutral will give only the single phase 127V reading. You also need to know how to connect an LCD screen to an Arduino although you can use an LCD screen shield which does most of the work for you. Upon startup, youll see a 3 Phase Energy Meter screen followed by cycling through the current, power, maximum power and kilowatt hours consumed screens. I have built the circuit as is in the schematic, but the current readings are always at zero with resistive load. The Arduino uno doesn't really have enough output pins to drive two LCDs but you could setup the LCD to change between two screens, one containing the cumulative kWh. I want to know the different DC energy meter and AC energy meter. Hope you enjoyed this Instructable? This article worked on 42A with a turns ratio 0f 1000:1 giving a secondary current of 0.042A or 42mA. fyp ieee

In order to do this accurately, you need to find a calibrated load. Notify me of follow-up comments by email. These are not easy to come by in a normal household so you will need to find something which uses an established and consistent amount of power. This instructable assumes you know the basics of Arduino programming, otherwise read my guide on getting started with Arduino. Reply So far Ive thought of two options: 1.

3 x CTs Talema AC1030 (See step for different options). Hope this helps and I have explained it clearly enough. In this case they were 11.8337 for phase 1, 11.8234 for phase 2 and 12.0325 for phase 3. Nice and useful project. [emailprotected], mam otazku dalo by sa merat s tmto meracom aj smer toku prdu napr. The code is simply saying that any readings below 516 are negative and should be discarded. Your calculations and components look correct. ubiq Because your setup, CTs , resistors and input voltages may be different, there is a scaling factor in the sketch which you will need to change before you will get accurate results, see below for calibration. Start by dividing your primary current (the maximum as used above) by your CTs turns ratio (available on the data sheet). How can this circuit be modified to have a 3 phase power loss monitoring system.

{ My 220V is wired on phase 1 and 2 so if I would be using 220V it would not be registered. I used a couple of incandescent light bulbs and spot lights, these come in a range of sizes and their consumption is fairly close to what is stated on the label, ie a 100W light bulb uses very close to 100W of real power as it is almost entirely a purely resistive load.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'the_diy_life_com-large-leaderboard-2','ezslot_12',176,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-the_diy_life_com-large-leaderboard-2-0')}; Plug in a small light bulb (100W or so) on each phase and see what load is displayed. The one used here is the Talema AC1030 which can sense 30A nominal and 75A maximum current.

Can I know what changes can be made to get the exact values of that? Searched some more and will start the build from scratch as the issue is resolved. I have drawn more current for testing but its just that, max 16.91Amps. Kind regards, Friederik. 2. Hi Jayd, Is there a reason you connect the burden resistor and the current transformer to the high side of the voltage divider (that creates the 2.5V reference). 4 years ago. If your load and grid tied solar inverter are both on one side of the CT and your main electrical connection is on the other side then if there is less load then what the inverter can produce then you could get a negative current reading. Thats exactly what I had in mind. I never realized how simple measuring 3-phase could actually be.

Thank you, Question Hi Michael, Reply It likely wont respond to 50Hz when measuring DC voltage, youll need an AC voltage measurement. This can be done very easily by stripping some of the wires away, soldering the burden resistor in and some heat shrink over the whole lot. Since writing up instructions on how to build a simple Arduino home energy meter which measured the energy consumption for a single phase, Ive had a number of people ask about modifying it to be a 3 phase energy meter. It doesnt seem that the correct RMS calculation is being done, plus there is math going on in the sampling meaning that the current waveform being sampled may not be fast enough With the SEGmeter codes I have developed, I have an array that I sample into, meaning the sampling can be as fast as possible. this is the calculation Reason I want to build this is so I can mount the display near my gate for the utility company to take the readings from, instead of them having to come on to my property to take the readings. This will definitely be one of my upcoming projects. add the squared sample into an accumulator variable So Idecided to take the opportunity to build a 3 phase energy meter and fix up a couple of areas in the original energy meters code which could have been done better. Please email me talema AS-105 750:1 Hi, can i measure 125 kw power using this project. c genial et merci beaucoup de maider ,mais jai loportunite a props ce projet de metre en oueuvre les information dans une aplication mobile a le but de diminuer la cosomation de mison par alerte cosomation dans chaque heure et donner des solution pour le diminuer. You need to measure the voltage as well to make an accurate inductive and capacitive load meter. With a few changes to the code, you can also add your local tariffs and display the cost of electricity used to date. The closest standard resistor value is 56, so this was used. I can get around 4kHz sampling using the 16Mhz arduino. Federico C. Hi Federico, Here is the three phase energy meter modeled in Autodesk Circuits so that the code can be simulated. Question This will enable you to measure true power rather than apparent power and should also improve the accuracy of your meter. You will now need to adjust the scaling factors defined in line 8 accordingly: double calib[3] = {11.8337,11.8234,12.0325}.

Youll need to build a meter which measures and logs both the voltage and current produced in order to accurately estimate power and energy produced. 75Ohm resistor

Here is a guide to connecting an LCD screen without the shield: https://www.the-diy-life.com/connect-an-lcd-screen-to-an-arduino/. I wanted to measure the output from the wind turbine itself which is not an true RMS, the rated frequency of the wind turbine is 32Hz. Connect a analog board to a nodeMCU. Im not aware of any specific shields designed for the Arduino Uno which provide WiFi connectivity. This meter measures the supply current through each phase using a CT (current transformer) and then does a few calculations to give you the current, power, maximum power and kilowatt hours consumed for each phase. So I decided to take the time to build a 3 phase energy meter and fix up a couple of areas in the original energy meters code which could have been done better. Why not just measure the positive component between GND and Ax and ignore the negative component (maybe add a diode to protect the analog input pin)? Also, in your energy meter can you show cumulative values of the parameters of all the 3 phases as a single value of power and energy? Hello, Yes you can, have a look at our post on the Simple Arduino Energy Meter for coding to the serial monitor. Another thing for Arduino and this kind of stuff, which is useful for current sensor selection, is that many sensors have a 0.333V output. I have an installation of three phase without neutral so not sure how to adapt the project to make it work for my situation? Either use linear scaling to calculate this figure or, if youre not good with math, play around with different values until the load you have plugged in is shown on the energy meters screen. To calculate how many amps yours needs to sense, take the maximum continuous power your are expecting to sense and divide that by your voltage (usually 110V or 220V depending on your country). The capacitor used is 10F which should be sufficient for most CT ranges for household applications. Connect a esp8266 module to an Arduino Uno.

Also choose 1% or better tolerance burden resistors AND make sure the wattage is applicable to the CT! If your LCD is connected to the same pins as used here and your CT is connected to the same input pin, you should at least get the screens populated with some figures although these will most likely be incorrect and some may be negative. This will tell you whether you have a hardware or code problem.

Upon startup, youll see a 3 Phase Energy Meter screen followed by cycling through the current, power, maximum power and kilowatt hours consumed screens. An Arduino only has analogue voltage inputs which measure 0-5VDC, so you need to convert the current output from the CT into a voltage reference and then scale it into the 0-5V input range. Cant explain it myself maybe you have an idea. If you are going to be installing your power meter somewhere permanently then you may want to solder the resistors and capacitor directly onto eachCT so that they cannot come loose. It depends what youd like to do with the WiFi but I think your first option (connecting the ESP8266) would be the easiest. Sure, for perfectly accurate measurements you need to measure both the supply current and voltage but for this application and in the interests of keeping the energy meter simple and safe only requiring a non-contact connection to your mains Ive decide to stick with a simple current measurement which gives you an estimate to within a couple of decimal points of a kilowatt hour. email me please NB Be careful when connecting the CTs to your mains and make sure that the power to your board is switched off before doing anything in the mains box. Then connect the +ve sides to adc1, adc2 and adc3 (with burder resistors on each). Is it possible made input voltage and calculate with this? Good luck! Hi meassure is not good, because, there is problem with voltage.. some times 210 some times 239 .. then is a lot of difference. Keep on posting! How can I apply items without LCD Shield just waiting for some stock to put everything in a case then i will mail you pics of the setup i made. With same current its repeating identical every 20millisec (230ac -50hz) It seems that the 16,91 amps corresponds with a 5volt amplitude (but its only there for a short while, I geuss this is why the multimeter reads 2.5V all the time. The other option would be to use an Ethernet shield and then plug in an Ethernet to WiFi adapter. Since writing up thearticle on how to build a simple Arduino home energy meter which measured the energy consumption for a single phase, Ivehad a number of people ask about doing a 3 phase energy meter. If the project succeeds I will send you some pictures and comments. The sketch. Question That sounds like a great addition to the project. Doesnt matter if i draw 1amps or 16amps. Are they not changing or are all three giving the same reading? Share it with us! Hi Dave, Simply how this should be done is: Then it will be more precision. Adding math here slows this considerably! How do i get started in debugging it? The LCD screen shield already picks up on the analogue inputs but only A0 is used by the shield for the button inputs. 16.91amps x1.414=almost 25Amps Your analogue reference voltage to the Arduino is 2.5V so to determine the resistance you use R=V/I R=2.5/0.042=59.5. This meter measures the supply current through each phase using a CT (current transformer) and then does a few calculations to give you the current, power, maximum power and kilowatt hours consumed for each phase.

So for scaling the CT output to suite your Arduinos analogue input voltage, you need to select a maximum current youd like your energy meter to sense which should be between this range. The code also looks a bit different to the code supplied in the link, it is just the order of elements which is different, the content is the same. Today i hooked up the oscilloscope and found that there is a dc signal on the analogue lines which amplitude grows with higher AC current. ), In Sizing The Burden Resistor section you mention: There is a bunch of other stuff I can share, and hit me up if you would like any more tips! RMSCurrent[i] = ((maxCurrent 516)*0.707)/calib[i]; //Calculates RMS current based on maximum value and scales according to calibration Finally you need two dividing resistors to get the 2.5V reference voltage from the Arduino. For example, if the overflow happens at 10000, the start millis was 9987 and the end millis was 2031, the difference would be 2031-9987=-7956 but the value cant be negative as it is unsigned so it becomes -7956+10000=2044 which is the correct duration. As mentioned above,because your setup, CTs , resistors and input voltages may be different, there is a scaling factor in thesketch for each CT which you will need to change before you will get accurate results. NB Be careful when connecting the CTsto your mains and make sure that the power to your board is switched off before doing anything in the mains box.

Id rather keep it to one board. The higher your maximum current, the high the power your meter can sense but the lower your resolution and accuracy will be for smaller currents. Again, with this meter Iwas going for simplicity. 1. If you're really only concerned with the total power consumed then you could just use a single CT on the neutral phase and that will give you the combined power consumption. What have you used it to monitor? For connection to a typical 3 phase mains supply, connect one CT around each of the phases as shown in the attached connection diagram. As it takes into account peak to peak amps not RMS values which makes You will now need to adjust the scaling factors defined in line 8 accordingly: double calib[3] = {11.8337,11.8234,12.0325}. But when i place it in my main electric case i always give the same current and power readings. talema AS-105 750:1

When using a CT like this even with a high turn ratio (not high turn ratio CTs are safer than low turn ratios) with an open circuit the CT becomes a voltage source meaning a high and dangerous voltage can be present! Thanks for the feedback. In this case they were11.8337 for phase 1, 11.8234 for phase 2 and 12.0325 for phase 3.

Dear Michael, thank you very much for sharing these plans. At 220VAC, it can theoretically sense up to 16.5kW for short periods of time but it is sized to continuously sense 6.6kW which is suitable for a small household. Do not remove any wires or remove any screws before checking your local regulations with your local authority, you may require a certified electrician to install the CT for you. hey there. This is correct, the circuit and CT will convert the current sine wave into a scaled voltage sine wave between 0 and 5V, which is then read in by the Arduino. Would that work? They must be the same value, so R1=R2 and we dont need much current so this articles uses two 100K resistors. In each case, the top line displaysphase 1 and phase 2s measurements and the bottom line displays phase 3s measurements. At 220VAC, it can theoretically sense up to 16.5kW for short periods of time but it is sized to continuously sense 6.6kW which is suitable for a small household.

Why is 2.5v reference voltage needed? Since most household wouldnt have too many low power factor contributors, the meter works quite accurately. its been a while and I eventually got the 3 phase up and working but regarding some fine tuning i just want to check some things in the code if you would explain it to me, if (maxCurrent <= 517) < where does this 517 come from?

Hi Tobias, thx for the post, my question is, how can I do to have also negative power as indeed I have photovoltaic panels and I want to now when I send power outside Is it also possible to add only 1 transfo to mesure the voltage? First you need to start by assembling your components onto the CTs to create the current sensors which produce a signal which your Arduino can understand. I tested the setup with 3 lamps on a 3ph net and it worked great. 3 years ago. (and then calculate the real power with emonlib ? in the tech specs the CT has a 3.5 audio plug and according to the specs, they are output on the tip and near the plug. Either use linear scaling to calculate this figure or, if youre not good with math, play around with different values until the load you have plugged in is shown on the energy meters screen. If i had the room Id used the same comonents to copy your setup but I have restricted space for the CTs This article worked on 42A with a turns ratio of 1000:1 giving a secondary current of 0.042A or 42mA. My mains are 3 wired, phase 1, 2 and Neutral. Can you please explain ?

It is about 0.5 mm / 25 gauge wire. Each CT should only have one wire/phase running through its core. Question Participated in the Microcontroller Contest 2017. 2 months ago 5 years ago. https://github.com/samotage/Aiko/blob/master/SEGmeter/seg_meter_v0_199.pde. Again, with this meter I was going for simplicity. It was quite gud to do and was very simple to implement . The Arduino analogue input ideally maps the AC current sine waveform from 0 1024 with the mid point at 512. Good luck, sounds like an awesome project to try! Simply solder the fiveleads from your current sensors onto the pin headers on the shield and use A1 to A3 as your sensor inputs as shown below. https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/interface-with-arduino?redirected=true

30ampsx1.414=42Maps as used in the example Hi Harshini,

Sizing The Capacitor & Dividing Resistors. It would certainly make the circuit simpler. Hi Michael, The regular Arduino jumper wires should suffice? Because your setup, CTs , resistors and input voltages may be different, there is a scaling factor in the sketch which you will need to change before you will get accurate results, see below for calibration. I was about to purchase an Arduino Uno Wifi board but it seems they are no longer making them.

1 year ago, Thank you fo the information. is this porject using dc or ac energy meter? fill up the sample array for the desired number of samples. What do you mean by the same current and power readings.

So you should see a change in amplitude if the CT is sensing more current. This project assumes you know the basics of Arduino programming, otherwise read our article on getting started with Arduino, and that you know how to connect an LCD screen to an Arduino. if (maxCurrent = 517? Yes at the moment since they're allowing us to call and give our meter readings they might as well just read it off a display. Best regards Simply run the array from 0-1 instead of 0-2. A couple of notes based on my experience! The one used here is the Talema AC1030 which can sense 30A nominal and 75A maximum current.

Your entrance or front door to your home is the first thing people look at when they walk past, drive past or come to 12 Ideas To Use Ordinary Things In Extraordinary Ways, Using Arduino Functions Correctly, Make Your Code More Efficient, https://github.com/samotage/Aiko/blob/master/SEGmeter/seg_meter_v0_199.pde, https://www.the-diy-life.com/connect-an-lcd-screen-to-an-arduino/, https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/interface-with-arduino?redirected=true, The reTerminal E10-1, the First Expansion Board for the reTerminal, What Makes TMC2208 Stepper Motor Drivers Silent, I Made A Home Assistant Hub Using The Atomstack X20 Pro, Recondition a Lead Acid Battery, Dont Buy A New One, DIY Raspberry Pi 4 Desktop Case With OLED Stats Display, How To Upgrade Your Homes Entrance & Increase Curb Appeal, 3 x CTs Talema AC1030 (See below for options and purchaselinks), CTYRZCH SCT-013-000 100A Built In Burden Resistor . With support for GSM module to send sms when there is loss of power supply. Are the readings staying the same as when the lamps were connected? Hi Adam, When i do a test setup everythings works great i have different reading for power and current dependent on the load i use on one of the 3 phases.