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  1. #1
    just me duncan drennan's Avatar
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    Mains voltage logger

    Does anyone know of a cost effective mains voltage logger that can either download or be connected directly to a PC? It should be able to do both single and three phase measurements.

    My dad is having a problem at one of their clients, and they want some info to back them up in their dispute with the municipality.
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    Silver Member Graeme's Avatar
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    I borrowed a mains voltage logging device years ago when electric motors on my property started burning out. The device produced a graph on a roll of paper that gave a continuous read-out of the voltage at my home. The graph looked like all the proof I needed to have the local electrical distributor pay for the burned-out motors. Alas, the response was that the reading did not coincide with the dates on which the motors packed in, and the device had not been calibrated. I was getting all set to take further readings and take the distributor to court when a friend in the legal profession warned me that the distributor would go to any lengths and any cost to repudiate my claim. I took his advice and abandoned the attempt.

    If you use one, make sure you get a certificate of calibration before and after you use the device.

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    i think i was or still am the only electrical contracting company in south africa who owns a fluke 435 which is a class A unit which can be used in court a battle against the municipaliy if there is a dispute...and i am in the process of investing in 5 amp cts for metering as i have found a demand for this kind of work especially in high voltage systems.

    there is no other instrument that i know of which has the accuracy of the 435...i could be wrong.


    ther is a company in westmead who say they specialise in metering called EVT i dont have the details but i am sure you will find their number in the book.

    there are lots of intrument out there which can measure KWH but how accurate they are and whether or not you would have a case against the municipality i cannot answer that question.

    the cheapest option would be just to buy a kwh meter from your local electrical wholesaler and connect it up and see if the read out is the same...just make sure the cts are the same ratio etc.

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    the contact details for EVT 031-7008212 or cell 0836516577 email evtech@yebo.co.za

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    all my equipment is calibrated on a yearly basis which is requirement for most fluke products.

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    just me duncan drennan's Avatar
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    The dispute is in East London, and has to do with voltage levels, not kWh.
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    Diamond Member AndyD's Avatar
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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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    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

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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

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