Indeed.
It is.
I always thought that 230 - 10% was 207.
So what is the problem with a supply varying between 226V and 253V when the allowed range is 207-253?
Indeed - but the nominal hfe (if called 'nominal', rather than 'minimum') is, in the 'graded components' situation, nevertheless related to the average hfe of components with that 'nominal' value (the average being approximately the midpoint of values for that 'grade'). I'm actually not convinced that many manufacturers would call the minimum value the 'nominal' one.
This whole argument seems to exist because of the apparent obsession in some people with declaring the range of voltages as a simple range rather than "arbitrary nominal ± tolerances" - as if it actually matters.
Yes - but, by legislation (if e-marked), the declared 'nominal' weight is required to have a specified relationship to the average weight of actual bags of sugar.
It matters in the sense that the way in which is is done implies that 'nominal voltages' (without the tolerances, which turns them into a range) actually 'mean something' - which they don't (unless/until we eventually harmonise the actual supply voltages to correspond roughly with the arbitrary 'nominal' ones).
Not at all - what makes you think that?
Whoops - my arithmetic went a bit awry there. However, I'm sure you understand my point, and I will correct the original post.
[I presume you mean 216V] No problem, per se. Detlef is concerned that suppliers might take advantage of the additional ~9V wiggle room at the bottom and allow some supplies to fall to a level at which current equipment (designed to work above 216.2V) might not function satisfactorily.
IME, they all do.
Yes, that's what I said.
No, that witnesses to the fact that the UK was successful in arguing that the tolerances around the nominal value would encompass the actual values of our supply, so there was no need for it to change.
Yes, but, as I went on to say, in contrast, the declared 'nominal' electricity supply voltage has, and is not required to have, any relationship whatsoever to the average of actual supplied voltages.
I would have thought that the requirement for 95% of the 10-minute average values during a one-week period to remain within the specified tolerance is pretty fair evidence of a relationship.
Perhaps not at the moment. But if the DNO's are, in effect, given permission to operate to the lower limit by the new standard, don't you think it's likely they may well make use of that in the future? Imagine increasing demand at the end of a long rural stretch of 240/415/480V (oops, make that 230/400/460V) distribution. If they can get away with allowing the voltage at the last house on the run dropping to 207V instead of having to maintain it at 216V minimum, don't you think they may well do so? They may well even adjust the transformer taps to deliver over 250V at no load in order to satisfy the 207V minimum at full load at the distant end. That means that the delvered voltage to that last house could well vary between over 250V during times of negligible load to 207V at peak demand.
If there was no need for the actual parameters of the U.K. supply to change, then why was there any need to change the parameters on paper?
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