On 03/30/2010 01:53 PM, Jones Beene wrote: > Stephen, > >> "Unfortunately he never showed actual real time volts and amps going in, > so it's anybody's guess how "true" the RMS numbers from the Fluke 123 > really are (unless you've run your own tests on that particular meter). > Sticking the label "true RMS" on something is a lot easier than making > it really produce a true RMS reading, particularly when it's generating > a real time trace rather than a single number." > > Yes, I think you answered you own question...
No, I didn't. Guessing that the Fluke might be wildly inaccurate on asymmetric square wave input is a working hypothesis, something to be checked, but it's also akin to condemning a CF experiment because there might be an "undiscovered error" in it. Without evidence to support it, it's just a guess. (Raw V and I curves would constitute such "evidence", to either confirm or refute the guess.) > but there is/was a dedicated > Y!Group for the MAHG at one time, and all of this should be in those > archives - if the group did not die off. Do you by any chance have a URL? > As I recall, Naudin simply took an amp reading and in some kind of mental > lapse, divided it by twenty, supposedly to account for the 5% duty; and > labeled it "true RMS". He's using the Fluke 123 "true RMS" digital scope, with graphical output, to measure amps and volts. If there's any division by twenty going on it's not documented on that page. Current measurements are shown as graphs, not single numbers, which also militates against the claim that he did a simple division by 20 after taking a reading with an ordinary ammeter. > Terry might remember it better, but it is my > recollection that a number of EEs who were on the forum at the time agreed > it was a stupid error. No problem there - we all make them; but the failure > to correct the problem is my issue with both Naudin and Moller - who > continued to use the results for years to raise money for his GIF.net (which > hired Naudin) despite being warned many times of the error. > > Jones > > >
