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Thread: Mains voltage logger

  1. #11
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    Mains logger

    Hello to the forum.

    I Realize this is an old thread but reading it, I thought some maybe interested.

    I have been working for a while now to optimize my own power consumption.
    In doing so, I used my Fluke 287 and Scopemeter 199 to do most my initial monitoring.

    I realized that to correctly save, you have to know what you are using and what the mains condition is like.
    The Fluke kit is not ideal to be left dedicated to this task so I built my own.

    The system comprises of a 16mhz CPU (Atmega128) with 8 AD converters and real time clock.
    Initially the plan was to have 1 voltage input and 7 current sensors.

    I then realized that having a real time graph of you main phase is actually all you need so I only equipped 2 CT's and 1 voltage sensor. I was not targeting 3 phase but the concept will apply.

    Anyway the point is I know have Real power graphed in this minute, this hour, last 60 hours.
    It also show power factor, wH, voltage, current, price and voltage/current waveform.
    The output compares very well with the Fluke 199 considering I only have 16mhz and can only do 1 AD conversion every 3 cycles.

    I considered adding a SD card for logging but dropped the idea because the graphs where more than necessary. Comments in this thread are making me think this is requirement.
    Any suggestions of other features welcome.

    The legal aspects of being able to use this data in court was never my intention because even top of the range kit can be discredited in court for many reasons. The intention was to make this information available/affordable so that it could be left in place in the average home permanently.

    To give you an example, my house normally idles at 300Wh at around 230V. The last few days the mains voltage has been up at 247V and my idle consumption is sitting at over 500Wh.
    So I know suspect I am paying more due to the high mains but my load is the same!

    I didn't think there was actually a market out there though as most people don't care/understand. This thread has me thinking otherwise though.

  2. #12
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    A nice little project by the sounds of it, sounds like it was a great success. There's a fairly new product that will do this and also connect to your computer to give you graphing etc. The Owl monitor; see here http://www.radiant.co.za/index.php?p...08&sc_id=308-8 It won't give you realtime monitoring results however but it certainly simplifies it for the average home owner who isn't up for building a DAQ setup from the ground up.
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  3. #13
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    Hi Duncan,I have just completed some consumption investigations which involve the local Municipality.If you looking at not spending a lot of money, then ascertain the following.
    (a)What is the make of meter that the Municipality is using? Normally you can contact that company and procure the same meter or even a test meter.
    (b)Make sure that it has a valid calibration certificate. This you can get from Eskom or even the Test and Metering section of the Municipality with which you have a dispute.
    Attached is a sample of a load profile that I took recently. The meter that was used is the same type that the Municipality uses.

    Hope this help somewhat.
    Attached Files Attached Files

  4. #14
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    AndyD, I have looked at both the Owl and MieO. Both are very basic and provide a very basic estimation. They don't even measure voltage and assume it to be a constant.

    The last few days my voltage has been sitting at 247Vac, today 223vac. They only read apparent power. They only update evert minute or so.

    I wanted what a fluke 199 could display but 25 x cheaper, I think I've got there.
    You can't compare 2gb sampling 5k sampling though but for 50 hz there is no problem.

    Logging stats is not a problem but providing a certified product will change the target price of R1k to more like R10k. I don't even know if people will buy at R1k

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    example of displayed data

    These are screen shots of the item. The layout is a bit crude at present but I am more interested in the values for now than prettiness:
    Main screen

    voltage and current waveform

  6. #16
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    I am not sure about the Municipality. At 1 point I complained about the quality of my inbound mains. A truck came around and they had a screw driver.
    The used my fluke 287 but when I showed them the reading on the scopemeter 199, they new nothing..

    Basically all the local guys know is:
    1) are the lights on
    2) are the lights flickering..

    I am sure there must be some high level guys there somewhere but they are well hidden.

    Anyway you will never win a dispute with the council, they will just refer it to legal and besides they have a max liability of R1000.
    The idea was to have a device that you can use to correctly manage your usage which would accurately reflect what council meter says.

  7. #17
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    i have a small problem in a building used by an IT company...i have a piece of equipment installed on site to prevent a disaster again where they cut the neutral cable and blew the living daylights out of all their equipment...now we have a bigger problem because the voltage is so unstable that it keeps dropping out the contactor...i have it set to 190 and 250 volts and it stills drops out...

    so i connected my fluke 435 to the system to find the voltage drops as low as 181 volts at any given time...so i contact the durban electricity department...get 5 phone calls from various people who have been to site to sort out the problem on the same day...i sit months later still with the same problem and no answers.

    when i asked the one so called sparkie what he was using to test the voltage i was told he had a multimeter...i can only shake my head and bang it against my target on the back of my office door...and take more medication to keep calm...when i approuch the electricity department to offer my service unfortunately i am not the right colour and am only 100 % BEE so i cannot assist then.

    so we have taken other measures to improve the volts stability.

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