UK mains voltage

Scott wrote:

I thought synchronous clocks were pretty much a thing of the past.

No, though diminishing slightly. Our new microwave oven's clock is quartz
controlled, and it's a pain. The last one was mains synchronous, and as it was
positioned next to the conventional oven that also has a mains sync clock, I
had both set to within a faction of second of each other.

The new one as I soon discovered was quartz controlled, and gained about 10
seconds a day. I took it back, and exchanged it for another. That was even
worse, 15 seconds per day. At that point I threw the towel in, and simply
don't set the clock. It sits there in standby with its cursor flashing, and of
course now doesn't need to be on permanently, so good for the planet :-)

--
Mark
Please replace invalid and invalid with gmx and net to reply.

On Sun, 15 Jun 2008 18:17:00 +0100, Mark Carver
wrote:

Scott wrote:

I thought synchronous clocks were pretty much a thing of the past.

No, though diminishing slightly. Our new microwave oven's clock is quartz
controlled, and it's a pain. The last one was mains synchronous, and as it was
positioned next to the conventional oven that also has a mains sync clock, I
had both set to within a faction of second of each other.

The new one as I soon discovered was quartz controlled, and gained about 10
seconds a day. I took it back, and exchanged it for another. That was even
worse, 15 seconds per day. At that point I threw the towel in, and simply
don't set the clock. It sits there in standby with its cursor flashing, and of
course now doesn't need to be on permanently, so good for the planet :-)

Good point. I was thinking about clocks themselves and forgetting
about time displays on applicances. Radio and TV equipment I assume
always takes its time from the broadcaster so we are left with
microwaves, cookers etc.

I must say I have not noticed them losing 10% or whatever was being
suggested earlier.

In article , Scott wrote:
Good point. *I was thinking about clocks themselves and forgetting
about time displays on applicances. *Radio and TV equipment I assume
always takes its time from the broadcaster so we are left with
microwaves, cookers etc.

When you stop and think of the number of things about the house that
include clocks, there are quite a lot-

Quartz crystal clocks (5)
MSF clock
Mains driven clock
Video recorders (3)
Computers (3)
ADSL router
Portable radio
Internet radio
Central heating timer
Microwave cooker
Landline phone
Mobile phone
Car clock
Digital camera

Some of these things correct themselves automatically from external
references, some of them are supposed to but don't, some of them do but
the external reference can't always be trusted, some of them do but not
reliably, and some of them just don't because they're not meant to.
We've got more timepieces than ever before, but I wonder how many of us
are any more sure of the time?

Rod.

"Scott" wrote in message
...

I thought synchronous clocks were pretty much a thing of the past.

Well the timeswitch that changes my electricity from peak to off-peak is the
old synchronous type. Next to the crappy LCD meter that they gratuitously
changed from the nice, easy to read magnetic meter.

I'm surprised they don't incorporate the timeswitch into the meter box,
except I expect they haven't worked out a way of enabling it to cope with
power cuts like the old one.

--
Max Demian

In message , Max Demian
writes
"Scott" wrote in message
.. .

I thought synchronous clocks were pretty much a thing of the past.

Well the timeswitch that changes my electricity from peak to off-peak is the
old synchronous type. Next to the crappy LCD meter that they gratuitously
changed from the nice, easy to read magnetic meter.

I'm surprised they don't incorporate the timeswitch into the meter box,
except I expect they haven't worked out a way of enabling it to cope with
power cuts like the old one.

The clock in my central heating controller (installed about years ago)
seems to keep remarkably good time (seems spot-on at 7:30am, when the
boiler fires up), so I've always assumed that it is locked to the mains.
It doesn't lose time when the power is off, so there's obviously a
battery in there too (presumably rechargeable), and a free-running
oscillator. At least, that's what I'm guessing.
--
Ian

On Sun, 15 Jun 2008 16:05:43 +0100, charles
wrote:

it reads as though the demand for electricity was exceeding supply ;-(

that's precisely what happened
http://news.bbc.co.uk/1/hi/england/7423169.stm

--
http://www.kingqueen.org.uk
remove .lartsspammers to reply

"Ian Jackson" wrote in message
...
In message , Max Demian
writes
"Scott" wrote in message
. ..

I thought synchronous clocks were pretty much a thing of the past.

Well the timeswitch that changes my electricity from peak to off-peak is
the
old synchronous type. Next to the crappy LCD meter that they gratuitously
changed from the nice, easy to read magnetic meter.

I'm surprised they don't incorporate the timeswitch into the meter box,
except I expect they haven't worked out a way of enabling it to cope with
power cuts like the old one.

The clock in my central heating controller (installed about years ago)
seems to keep remarkably good time (seems spot-on at 7:30am, when the
boiler fires up), so I've always assumed that it is locked to the mains.
It doesn't lose time when the power is off, so there's obviously a battery
in there too (presumably rechargeable), and a free-running oscillator. At
least, that's what I'm guessing.

The thing about electricity meters is they are expected to run for at least
ten years or so without any maintenance, and batteries, rechargeable or
otherwise, can't be relied on to last that long. And a purely quartz clock
would likely drift a significant amount in ten years. I suppose they could
use mains synchronisation with a quartz reserve powered by a capacitor. I
think they make special low leakage capacitors for the purpose.

--
Max Demian

Your UPS has picked up the low frequency event on 27th May when the grid
frrequency fell to around 48.7Hz and caused operation of the automatic
under-frequency load-shedding in parts of England. (Some set at 48.8Hz).
The electric clock correction is constantly applied by setting target
frequencies of 50Hz or 49.95Hz or 50.05Hz depending on whether the clock
error is almost zero, positive or negative respecively. The aim is to
keep it within +/- 10 seconds but it is not specifically 'correct' at
any particular time.

RodP (former engineer at a Grid Control Centre)

In message , Max Demian
writes
"Ian Jackson" wrote in message
...
In message , Max Demian
writes
"Scott" wrote in message
...

I thought synchronous clocks were pretty much a thing of the past.

Well the timeswitch that changes my electricity from peak to off-peak is
the
old synchronous type. Next to the crappy LCD meter that they gratuitously
changed from the nice, easy to read magnetic meter.

I'm surprised they don't incorporate the timeswitch into the meter box,
except I expect they haven't worked out a way of enabling it to cope with
power cuts like the old one.

The clock in my central heating controller (installed about years ago)
seems to keep remarkably good time (seems spot-on at 7:30am, when the
boiler fires up), so I've always assumed that it is locked to the mains.
It doesn't lose time when the power is off, so there's obviously a battery
in there too (presumably rechargeable), and a free-running oscillator. At
least, that's what I'm guessing.

The thing about electricity meters is they are expected to run for at least
ten years or so without any maintenance, and batteries, rechargeable or
otherwise, can't be relied on to last that long. And a purely quartz clock
would likely drift a significant amount in ten years. I suppose they could
use mains synchronisation with a quartz reserve powered by a capacitor. I
think they make special low leakage capacitors for the purpose.

The '15' (years) went missing in my previous post. I'm not sure whether
the backup storage device is battery or capacitor. 15 years is probably
pushing it for a Nicad (although I do have some RS C-size Nicads from
1982 which still appear to work). I can't remember whether the LCD
display still functions when the mains is off, but I suspect that it's
off. Must check sometime. Fairly recently, we had a power cut for about
10 hours. I was surprised when the time was correct when it can back
again.
--
Ian

Max Demian wrote:

The thing about electricity meters is they are expected to run for at least
ten years or so without any maintenance, and batteries, rechargeable or
otherwise, can't be relied on to last that long. And a purely quartz clock
would likely drift a significant amount in ten years. I suppose they could
use mains synchronisation with a quartz reserve powered by a capacitor. I
think they make special low leakage capacitors for the purpose.

The time switch at my parents' house for off peak/on peak switching had
a spring reserve. Their power was off for almost a week in October 1987,
the clock ran out of steam after about three days. When power was
restored there was a loud noise as the spring wound up again.

The SEB never bothered to come out to reset the clock, my folks weren't
too fussed because the new on/off times suited them better :-)