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  1. S

    shorting coils on an alternator

    I guess in essence I am wondering in what situation it is "good practice" to short the coils on a generator? I seem to be thinking of it as short-circuiting a current source: one would never join together 2 of the three phases at a 400V mains supply just to get a higher current for a singlephase...
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    shorting coils on an alternator

    Pls excuse this posting which is somewhat off topic but purposeful to tap into a community without "accepted" bike-lore opinions. I am a stranger to the world of vintage bikes. An uncle who has become recently into nice old British bikes has asked me about wiring and converting alternators from...
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    single phase off a three phase genny

    what are the implications of using a 3 phase generator to deliver a single phase load? ie, just using one of the phases.
  4. S

    198 kHz qrt

    thought I ought to mark the occasion not that anyone cares
  5. S

    the thorny issue of lime

    internal pointing. purpose (as I see it) is two-fold: 1. to reduce the natural dusting effect that would otherwise occur from the traditional clay filler-mortar material and/or lime-plaster render. 2. to give an aesthetic effect If framing & lining an internal masonry wall, the goal is to...
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    the thorny issue of lime

    Quite so, but the stone can still spall in any orientation. is that bad? seems not as long as the layers cannot displace too far.
  7. S

    the thorny issue of lime

    I see what you mean. I was meaning that the olden days were just different in so many ways, chiefly to this argument the perceived lack of time, relatively higher cost of labour, and harsher precipitation in this region meaning that doing it "properly" is no longer as viable as it was. so I...
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    the thorny issue of lime

    why would the stones spall with evaporation?
  9. S

    the thorny issue of lime

    I have developed a theory on which I would welcome comments Specifically Northern Orkney Islands traditional building, where the main material is locally quarried "Caithness Flagstone". The actual stone used in any given building is somewhat variable in quality, with certain stones being soft...
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    practical interpretation of insulation readings

    small (so-called inspection class) ROV. testign for insulation on the umbilical connection to a manual umbilical reel via sliprings. 500V DC nominal down the line. protected from lethality by a patent LIM
  11. S

    practical interpretation of insulation readings

    in the field, at potentials < 1kV, with "any old megger" I contend that: Insulation readings of >= 1Megohm on the megger's 1kV setting, indicates "good to go". insulation readings between 250k-1M: "keep yer back to it and lets see what happens when energised" insulation readings below 250K...
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    messing around with ebikes

    OK so ericmarks experience indicates that their may be significant differences between machines. I can see that fundamentals like mid-engine vs rear hub motor may be different. my feeling (and I admit that this is based on very scanty practical) is still that this is one of those...
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    messing around with ebikes

    Good shout, simple coulomb-counter.
  14. S

    messing around with ebikes

    Anyone got any experience bodging up e-bikes with BLDC hub motor at subsystem level? I have developed some broad theories on the arrangements so far, based on my vast experience of : guessing a diagnosis of failed and unidentifiable controller on one problem bike, taking a punt on something...
  15. S

    outside pir lights that last longer than 10 months

    can anyone reccomend external PIR lights that will last some reasonable length of time? ideally >36 months
  16. S

    Buzz Wire game / Steady-Hand game

    gaaaah yeah true but wired wand detracts from dexterity with intelligent control you could get around the fingers-as-barrier thing also you could just lightly touch the things together and maybe the resistance too high to get a good ring on the bell? know whatcha mean though.
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    Buzz Wire game / Steady-Hand game

    skoool Xmas fares coming up in community centres in these parts. I have wanted to do a giant buzz wire game thing for ages. I remember back in the 80s a local electronic firm did one for the school, just a simple affair with a telephone bell & shiny brake-pipe "route" to trace the (wired) wand...
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    TDR with a VNA

    any RF bods done any practical TDR'ing with the latest budget VNA's that are now available? I have a miniVNA pro and a JNCRadio SV6301A, and I believe that both of these offer TDR functions.... was thinking of things like finding where the break in a cable that goes across the lawn to the garage...
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    Flue: to fill or not to fill

    I don't doubt that it (poured vermiculite filler) is frequently used, but I'm trying to work out if it's a good thing or not. you say "way before", what do you mean - do you mean to imply that you pour the verm then allow a period of time for drying, or you pour the verm, then allow a period of...
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    Flue: to fill or not to fill

    Old stone-built house, damp gable. ground floor + 1st floor, then small loft void. suspected primary cause of damp is chronically failed chimney/cap. I am in middle of replacing chimney/cap. Which is to say I've removed the failed chimney & concrete cap element as far as the top of the stone...
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