>From the National Grid (Who supply/transmit our electricity) "System frequency will therefore vary around the 50 Hz target and National Grid has statutory obligations to maintain the frequency within +/- 0.5Hz around this level. However, National Grid normally operates within more stringent 'operational limits' which are set at +/- 0.2Hz. " The figure of 50Hz is derived from the alternators rotational speed of 3000rpm, 3200rpm/60Hz for the US. Most government institutions from the Post Office to the Railways used to use mains driven clocks and it was made statutory that the frequency would always average out at 50Hz. Whilst trying to find WHY we chose 3000 and the US 3200 (Which I didn't find) I did come across some interesting sites one being the National Grid themselves with a 'live' frequency graph here: http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm and a snazzy live meter here: http://www.dynamicdemand.co.uk/grid.htm#
Even better, who says Nixie clocks are not accurate? See: http://www.leapsecond.com/pages/atomic-nixie/ including one of David Forbes Scopeclocks both "accurate to a few nanoseconds a day"! On 18 Jan, 20:00, Dutchgray <[email protected]> wrote: > > I guess that the additional question would be: How stable is the mains > > frequency in the UK? > > Its supposed to be stable and analogue clocks driven from the mains > were once the norm in public buildings. I would use it as a time base. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
