Rob Kimberley wrote:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Rob Kimberley
The electricity bill always states the times are approximately 0030 to 0730 GMT.
Therefore, there is no change for daylight saving.
Dave
-----Original Message-----
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dr. David Kirkby
Sent: 28 December 2009 23:22
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Can a quartz crystal go off by 2% ?
I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to
get
cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity
demand
is low. I'm no longer heating by electric, but do run some computers 24/7.
It's
not totally clear whether this saves me money or costs me money, as I pay a
higher price per unit during the expensive period, to compensate for the
fact I
get it cheap for 7 hours. But I run some computers 24/7. I guess I should do
the
maths and work it out. Apart from some heaters in the garage, which are very
rarely used, I no longer heat with it.
The time when the electric is cheap is set by a clock, which rotates
once/day.
It says on it "quartz" somewhere, so it must be regulated by a crystal and
not
from the 50 Hz supply, which would be pretty useless, as the clock would go
wrong if there was ever a power failure. The clock has not been changed in
the
17 years I've lived at my house, though the meter has on a couple of
occasions.
The clock used to keep accurate, but now it looses time about 30
minutes/day. I
wrote a computer program to predict when the electric is cheap, so we can
schedule when things like the washing machine, dishwasher, Hoover etc are
used.
Even cooking to a certain extent, if it's convenient, though our life does
not
revolve around the cheap electric.
I'm wondering if this is a mechanical fault in the clock, or whether the
crystal
has developed a fault. It's clearly well outside any tolerance or aging
process
of any crystal - even the cheapest ones.
I've not done any very extensive tests, but the error does not appear to be
constant. Hence every month or so I need to produce a new table, as my
predictions get less accurate with time. Since one can only read the clock
to an
accuracy of about 15 minutes, it's not easy to know how far it is out.
Sometimes
we hear the contactor go over, as this is supposed to then power the storage
heaters, which we no long use.
Dave
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
