Posts by andrea.s

    OK


    Bye


    This is a pity. Ahlfors was not spamming. Just proposing evidence that was hidden in plain sight, for others to ponder on. This has been the style of other Rossi-addicted mathematician bloggers for years. Not that I share his/her views nor do I always understand what he/she hints at. But I don't see what was reproachable. If there is a public record of Fabiani having an office space in the same dept as Roland Petterson it is an interesting find.

    The job title is likely self edited thus not significant.


    It is a self-ban following the warnings if I am not mistaken. If Ahlfors has the same personality as the other mathematicians we will never see him again whatever apologies are made.

    [...]

    Perhaps there should be a rule that only people with a reading comprehension above a certain level can participate. I don't know how that would work in practice.

    [...]


    Eric I normally appreciate your posts. In this case sorry to say but I find it hard to believe you entertain such a thought. Holy cow - this is a thread about Rossi, not Shakespeare or Wordsworth.

    Alan, Thank's for this lesson about [...] the English language.[...]



    LDM may I ask where are you from? it intrigues me that you have this insider information about the Lugano authors.


    And did you take a look at the spreadsheet and resulting COP when increasing the power input by lowering the triac delay. if you do believe as you say that a clamp may have been misplaced you may want to verify your statement about COP underestimation. It is underestimated at low drives as in the plots but largely overestimated when driving at AC Power representative of the test phase.


    You sound honest and competent and I suppose you would admit it if your judgement were mistaken.

    @IH Fanboy


    I'm with you on this one. I would suggest Dott.Rossi (instead of Dr.Rossi) to make it clear that it is an Italian courtesy.

    You see, I don't share the resentment against the man who has perhaps not invented the new fire, but whose deeds have emotionally involved and entertained all of us for so many years. If he gets into real trouble I would support an appeal for grace, though I may feel differently were it my money.


    Edit: thinking it over, if it were my money, then it wouldn't be me.





    Of course M.A. not M.Sc. , my mistake.


    Yes it is common although old-styled to call Dottore, and address as Dr. Someone in writing, someone with whatever university degree.


    That may explain why PhDs aren't that popular here. All those years and your title doesn't show up visibly to your neighbors and relatives unless you brag for it.


    Italians are traditionally obsessed with titles, so we call people Avvocato (Lawyer) Ingegnere (Engineer) etc. which probably used to sound respectful a century ago.


    I think I already mentioned a while ago that it is typical of illegal parking valets to call you Dottore in mocking reverence without caring to check your references. This applies to native Italians, whereas immigrants (the majority nowadays) use "capo" I.e. "boss" which is also pretty good for the ego.


    With that I must disagree. The new university system is now similar to the US with a bachelor and a master's degree in sequence. By no means the old system was less rigorous or easier. Universities now classify the previous degrees as a bachelor's or a master's equivalent based on their length and content. So if Rossi is a Dottore Magistrale you may well consider him a M.Sc.


    Then in terms of quality and rigour one can have any opinion. When I studied engineering the American textbooks looked funny to me with lots of pictures and little theory. Italian texts in fundamental physics and maths were ugly and boring but much tougher. And when we wanted to challenge our skills with University colleagues we went to the Russian association library where books in physics and maths had the toughest exercises and problems ever...



    On another note, to add to your list of dittos, one that amuses me is use of the (?) acronym AEG when referring to Ampenergo, just in order to impress whoever pays little attention with the resounding name of a historical German company (Allgemeine Elektricitats Gesellschaft) that -among else- built nuclear plants in Germany.

    :/

    Is there any truth to this?


    As usual a half truth.

    Rossy has a degree in Phylosophy.

    Not sure whether it equates to a bachelor or a master, because at the time it was a 4 year course requiring a final thesis. edit: the attachment by Can shows it equates to a Master's degree.


    In Italy you are called Dottore with such a degree.


    To call it a Doctorate in the US is obviously misleading, as it is not a PhD. That would be a "Dottore di Ricerca" in Italy and require a couple years minimum research work plus a thesis after a Master's degree (with which you are a "Dottore Magistrale").


    Hi LDM


    First of all thanks for taking the time to comment on the spreadsheet.


    The situation you describe is the one at low input drives that matches the pictures in the appendix. Triac delay is set to 143 deg, and indeed for these low powers (132W real, 168W when inverting I1) the COP is underestimated. The spreadsheet (mockingly) states "COP" 0.8.





    Now if you change cell A3 "triac delay" from 143 to 87 and change Rload to 34.77 ohm to increase the input power in order to match the Ferrara March test (device named "HT2"), you get 2344W real, and 810W when inverting I1. The apparent "COP" is now 2,9 .




    [ETA: replaced data of device "HT" with "HT2" as the Ferrara test was single phase for "HT2" only]


    Herebelow an extract of the Ferrara report aka TPR1.



    [...]


    @IH Fanboy


    Good catch, now that I've seen it I remember. Ok so there it is, very clear on a single screenshot and easier than a polar plot. So all we need is one of the Ferrara and Lugano testers to post a screenshot from each actual test. I have been asking for this since a few years. I received a private reply from Rossi, mostly based on arguments ad autoritatem, but nothing from the authors. Levi dismissed this idea on the blogs, which is understandable, but there are other five or six people who were there to review the work as peers.

    Energy values will not change, only power, but these should be instantly apparent as to what the problem is.

    Embedded in the meter firmware should be

    Power flow analysis including phaser diagrams, if a current transformer polarity is reversed, the voltage and current will show up in opposite quadrants.

    As the load is primarily a heater there should be little if any reactive load, (power factor), so the current AND voltage should be physically close and in the same


    Yes the load is a heater with negligible inductance, but the TRIAC control delays the turn-on of currents.


    Nevertheless, the sequence in the vector diagram has to be the same : if it is V1-V2-V3 clockwise, it ought to be I1-I2-I3 clockwise. This could be checked for the Lugano test if a polar diagram were available.


    In the TPR1 (black hotcat) where there is no I3 , it would be even easier: I1 and I2 must be in opposite quadrants. If they are overlapped it is proof of a reversed clamp.


    Did anyone look at the PCE830 polar diagram in Ferrara or Lugano? I doubt. If they did, well: speak up!

    No, there was zero current on the third clamp. And while a reversed clamp would alter the total power calculated by the PCE-830, the power for each individual clamp would be calculated correctly, just with a flipped sign for the reversed clamp. Do you mean to tell me that you don't think Levi checked the power for each clamp individually?


    A clamp measures current, not power. If the clamp is reversed, the instantaneous value of current is read as its opposite. This is why the plots in the appendix are alarming: I1 and I2 are in phase instead of being in antiphase.




    The reading on the PCE830 display will normally show rms voltages and currents (which are by definition positive figures), and the total power (which is instead the algebraic sum of instantaneous powers V1*I1+V2*I2+V3*I3 averaged over the period). I attach below a sample image (credits to the GSVIT guys).

    [ETA: second screenshot is with one clamp reversed.. note the power sum dropping]




    IH Fanboy, I am not saying any of this is proof. But it deserves a reply with facts and not a dismissal.


    Consider that a clamp may be reversed by mistake, but also tampered with (inverting wires within).

    LDM


    You are right on the absolute powers in the spreadsheet. At some point I reduced the step from 1 to 0.5 degrees to have a better resolution and forgot to correct the average formula (for twice the no. of samples). Thanks for spotting that.


    This however changes nothing about the key point the spreadsheet wants to make, which is: when inverting a clamp (I1 in my spreadsheet) the power reading is wrong and the apparent COP varies with the conduction interval.

    For low regimes it may go down to 1 or less, and when increasing the conduction time (thus average power) it increases arbitrarily. If the current weren't chopped at all, apparent power would be zero, i.e. infinite COP.

    I will upload the corrected spreadsheet shortly.


    [ETA: uploaded the corrected spreadsheet in .zip format as well hoping formulas are readable that way]

    (.ods) https://drive.google.com/open?…ubncFIhCFaNF83OUgzUDcwenM

    tpr1_opensource_rev2.zip


    @IH Fanboy


    I doubt you can compute mentally (let alone with a half brain) the power out of a chopped AC waveform. I propose you take a look at the spreadsheet. Then if something isn't right I will apologize and correct. LDM claims different results but it is hard to judge without a schematic diagram.