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Thread: Mains voltage logger

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    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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    the cheapest unit i know of which can do what you want to do cost about R14000.00 3 phase...a fluke 289 can record min/max /avg but only single phase.

    you get a K5020 from major tech if you are looking for cheap.

    or you can get a 1735 which is the bottom of the range from fluke which will set you back about R30000.00

    the municipality should have recorders which they can fit and record.

    there must power quality experts around there...your local electrical wholesaler should be able to assist you with this problem.

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    Diamond Member AndyD's Avatar
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    If you need to log basics such as voltage, current, real power, apparent power, reactive power, phase failure, power outages, power factors, maximum demand etc etc and you need a cost effective data logger that will stand up in court (class 1 accuracy, Orbis compliant data capture, and calibration certified) then I would suggest use a consumption meter with logging capabilities. Here's a local three phase unit that retails at under three thousand Rands. It has adequate resolution and memory for at least a month of logging at its highest settings. For just voltage logging you don't need CT's or VT's so that would be the total cost. If you want to log currents or power figures then a set of 3 x split 5 Amp CT's of metering accuracy will set you back another R1500 - R1800 for all three (<500Amp). It will record under voltage events as alarms with complete info about event start and finish times, event duration as well as the actual voltages recorded. It comes with free capture software and will export directly int Excel for graphing. I doubt you'll find a simpler or cheaper solution that will stand up in court.

    If you need more complex logging such as harmonics or you need to capture waveforms for analysis then you'll need to go to the party with something more convincing. The cost of these types analyzer units will be 20 - 30 thousand Rands and upward.
    Last edited by AndyD; 16-Feb-10 at 02:45 PM.

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    this could be interesting...with the electricty increase of 35% coming into affect soon...and considering it has become our biggest household expense...i will be looking at converting to a pre paid meter so that the bill doesnt run away like it is at the moment.

    My PQA equipment is too expensive to leave recording for long periods of time this could be a cheaper option to leave on site.

    i am just too busy at work to look into my electricity consumption and ways to improve and lower useage.

    anyone looked into gas options...are they going to be cheaper when the electricity is increased...or i am gona have to build a fire place and fit a donkey for hot water and braai every night

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    Diamond Member AndyD's Avatar
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    Quote Originally Posted by murdock View Post
    anyone looked into gas options...are they going to be cheaper when the electricity is increased...or i am gona have to build a fire place and fit a donkey for hot water and braai every night
    Well with the increase in electricity price I can see a steady increase in gas demand happening over the next few years. I doubt it will be immediate but as people replace equipment such as heaters and cooking appliances then they will consider gas more and more as an option. Will the increased demand for gas result in it's price increasing? Probably, so the donkey may be the way to go ;-)

    Like you say, leaving you PQA equipment on site can be risky, at least with four grands worth of kit the insurance won't be so high and even if it's not insured it's not the end of the world if you loose one each year to theft. I wouldn't say the same for your Fluke PQA though. Also at 2-3 thousand Rands it's hardly worth sending them in for calibration every year, you might as well just buy a new one.
    Last edited by AndyD; 18-Feb-10 at 11:17 AM.

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