The nominal voltage did and has.
Age of meter
- Thread starter scantronic
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Pure meaningless paperwork exercise. The actual voltage has not changed which is what is important.
No need to, and it's better than the stuff they're installing new now anyway. No doubt it will be scrapped within a few years when the supplier has a changeout program, but if checked for calibration and re-installed that meter could still be going strong in another 40 years. Somehow I doubt the all-singing, all-dancing meters they're installing now will be around for a fraction of that time.
Grew up with 240/415 and now when folk talk about 230/400 the 400 part just doesn't seem right
There again I never managed to get my head around poundals and slugs. When doing mechanics at J1/J2 (pre ONC) if the answer seemed too low I multiplied by 32.2 and if too large divided by it
Was really glad we went to MKS, that at least seemed to make sense.
There again I never managed to get my head around poundals and slugs. When doing mechanics at J1/J2 (pre ONC) if the answer seemed too low I multiplied by 32.2 and if too large divided by it
Was really glad we went to MKS, that at least seemed to make sense.Sponsored Links
Would 398 sound better?
I grew up in the days of 210/365 V. IIRC it was about 1962 to 1964 that SWEB moved its customers in my area from 210/365 to 240/415. I remember we received new lamps (light bulbs) for free, and electric fires were taken away, and came back with new elements. Funny how this didn't happen when Europe standardised on 230/400!!!!!
Nor when HK went from 200v to 220v.
But 210v to 240v is a much larger change than 220v to 230v.
Much of southern California was originally 50Hz, with Los Angeles converting to 60Hz in the 1930's and many other areas in the late 1940's. The utility companies offered replacement/adjustment programs for synchronous clocks and similar devices.
When was that the voltage, I always thought it was 250volt originally.
i do see winstons point though the Actual voltage nowadays can be a bit erratic
It's not so much a question of when but of where. Different districts had different nominal voltages prior to the standardization nationwide at 240V. Some were as high as 250V, some were as low as 200V, and there were also a few places operating at 100/200 - 125/250V split-phase. Then there were d.c. districts with similar voltage variations.
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I suppose we look for rounded results so 220 volt single phase may mean 381.0512 volt three phase, but we call it 380 and going up by 10 volt we call it 380, 400, 415 and 440 the latter seems the odd one out as from single phase of 254 volt so quoting maximum voltage rather than mean voltage.
As to if important that depends on how the meter calculates watts. If it actually measures amps rather than watts then the voltage will make a difference. 13A can equate to between 2810.6 to 3289 watt according to if on top or bottom of the range. I remember having a loop impedance tester and 1.44 Ω would always when switched to prospective short circuit current would always show 166.7 amp what ever the voltage was, clearly it assumed 240 volt. I asked the question did it measure amps and convert to ohms or ohms and convert to amps? Likely measured amps.
I have never stripped a meter to find out if it actually measures amps, watts or VA would be interesting to know the answer.
As to if important that depends on how the meter calculates watts. If it actually measures amps rather than watts then the voltage will make a difference. 13A can equate to between 2810.6 to 3289 watt according to if on top or bottom of the range. I remember having a loop impedance tester and 1.44 Ω would always when switched to prospective short circuit current would always show 166.7 amp what ever the voltage was, clearly it assumed 240 volt. I asked the question did it measure amps and convert to ohms or ohms and convert to amps? Likely measured amps.
I have never stripped a meter to find out if it actually measures amps, watts or VA would be interesting to know the answer.
I can't speak for others, but Fluke MFTs certainly calculate PEFC and PSCC by dividing by the actual measured voltage by the loop resistance.
AFAIAA, unless one uses something like a Wheatstone Bridge, there is no direct way of measuring resistance - so it nearly always has to be calculated from voltage and current.
Kind Regards, John
The 440 figure is from a nominal 250V supply, which comes out as 433V phase to phase, so round up to 440V.
Physically your correct in that the measured line voltage for most people did not change and still measures around 240V today, what did change was the official nominal voltage what was changed from 240V +6% -6% to 230V +10% -6%, thus giving a new acceptable voltage range of 216.2V-253V.
So in essence all that changed was the official specification. Many sub transformers still put out 240V as they did back decades ago. Now for new sub transformers, I would guess they are designed to put out the more recent nominal 230v; although In reality they could put out anything between 216.2v and 253v.
I'd be interested to know whether that is the case. If I were them, I think I might be tempted to (still) stick closer to 240V (if not higher - see below), thereby giving more scope for VD before the voltage supplied to consumers becoming less than the 'permitted minimum'.
In fact, I would have thought that the voltage output from the tranny (and, indeed, supplied to the closest consumers) would already be a fair bit above 240V, so as to keep the most distant consumers above the minimum at times of high load, wouldn't it?
Kind Regards, John
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