Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Replies 25 replies
  • Subscribers 38 subscribers
  • Views 1468 views
  • Users 0 members are here
Options
You may also be interested in

Why is the accuracy of multifunction testers so low

Alan B

I am working on a scenario at the moment where my customer has an EV charger cutting out due to low and also possibly high voltage.
My KT65DL is indicating voltage as low as 214V and seeing swigs from 214 to 246 in a 1 hour period. The DNO are saying they don't trust the values being given and are declining to put a voltage logger in, asking for data from the EVCP manufacturer, which is unlikely to be available as it's Tesla and probably no more accurate.

But it's accuracy is +/- 2% plus 4 digits, so effectively +/-5V, which means it has very little value for checking the supply voltage is in range, also doesn't help that the sampling is quite slow and I assume minimums are being missed.

To my knowledge it's not that expensive to build reasonably accurate voltage meters, maybe AC meters cost more? But given multifunction testers cost £500 or more why is the accuracy so low?

Parents
  • 0

    Could you argue that typically a meter will read either high or low?  After all if it is say 5 volts - or more - out, then it will likely be in the same direction for the low and high voltages; it is not going to be reading low at the lower limit and high at the upper limit so as to give the DNO grounds to ignore it. Is it?

    Clive

  • 0 in reply to AncientMariner

    true - most of the error of any given meter and set up will be 'systematic', - by which I mean a feature of the system, like a gun that always shoots low, plus a much smaller random element that varies over time . There may also be trends, like the error changes in a repeatable way as the battery droops or the heating comes on .
    Mike

Reply
  • 0 in reply to AncientMariner

    true - most of the error of any given meter and set up will be 'systematic', - by which I mean a feature of the system, like a gun that always shoots low, plus a much smaller random element that varies over time . There may also be trends, like the error changes in a repeatable way as the battery droops or the heating comes on .
    Mike

Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines