Bob
You might be interested to know that during WWII in West London we
regularly experienced a drop in frequency during the day. We were told
that this was a method of lowering power consumption. It was not much
and presumable within legal limits but by the evening synchronous
electric clocks could be up to 8 minutes slow. However by the morning
they would be correct so presumably the frequency would be above the
nominal 50Hz (or should I say 50 cps as they were then) during the
night.
We did not have a National Grid at that time but I believe that all
London power stations were linked together.
Regards
>Off topic, but .... I've never heard of the power frequency (60Hz)
>'sliding' off, at least not here in the States. The voltage can drop
>from an overload--i.e. a 'brownout'--but the only thing that could
>change the frequency is generator speed changing. Since all the power
>producers--hydro, wind, gas, coal, nuke--are tied together in a grid
>they are precisely synchronized.
>
>Frequency would only affect an electromechanical clock--one driven by
>an electric motor. The Barbie clock is solid state--AC is converted to
>DC for use by integrated circuits (like the LED display). A frequency
>change would have little to no effect. Most modern electronics have
>switching power supplies--they rectify the AC to DC then smooth the DC
>with capacitors and step it down--converting back to AC or pulsed DC
>then back to DC--as required (+/- 3V, 5V, 12V, etc.).
>
>bs
>
>
>
>
>Josef.Eckert@t-systems.com wrote:
>> The Barbie clock radio is frequency triggered. It works well with a constant
>> 60 Hertz frequency. In Europe with a 50 Hertz frequency or when the frequency
>> slides off because of overload in the power supply system the clock could not
>> keep the time anymore.
>>
>> Josef Eckert
>> Konigswinter/GERMANY
>>
>
>
--
John Harper
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