On 22/08/2019 08:14, Steve Walker wrote:
On 22/08/2019 07:26, The Natural Philosopher wrote:
On 21/08/2019 20:32, Steve Walker wrote:
On 21/08/2019 20:02, tony sayer wrote:
In article , Martin Brown
'''newspam'''@n
ezumi.demon.co.uk scribeth thus
On 20/08/2019 23:04, Max Demian wrote:
On 20/08/2019 19:21, Andy Burns wrote:
Max Demian wrote:

How do that with sodding great dynamos all round the country
that all
work in different ways?

By all running at 50Hz, and getting them into sync before joining
them
to the grid.

I heard on a radio programme recently that the generator people are
relaxed about the overall synchronisation and they don't have clocks
saying "electric time" and "actual time" in the power stations so
that
"cooker clocks" might not be reliable. Does anyone know if this is
true?
There must be loads of synchronous timeswitches about, and quite a
few
clocks - I think I saw one in a local hospital.

They are legally bound to keep the twenty four hour average extremely
close to 50Hz - ISTR the exact tolerance is still an official secret.

Excursions 0.1Hz either way are not uncommon at times of heavy or
light
loading. They play catchup in the night and run slow in daytime.

A synchronous motor mains clock could be running 0.2% slow for most of
the working day so in an 8 hour shift it could drift by about a minute
in the employers favour. These days most modern systems are crystal
controlled and drift around 15s a month or less if trimmed.

Cooking wouldn't notice a 0.2% error in timing. GPS would!


Do that many clocks use the mains these days?, went to the leccy
wholesalers the other month quite a good range, all battery Radio ones
and aren't they using much the same or quartzÂ* on cookers and the
like a
lot nowadays?..

Probably any mains powered clock. Why bother using the crystal, when
mains frequency (over time) is more accurate? The crystals are then
only used for battery back-up.

One very simple reason. Cost.

A synchronous motor and gearbox costs more than a quartz crystal and a
chip and a stepper motor. Or digital LCD display.

Most mains clocks are digital these days and do time themselves from the
mains. Built into ovens, cookers, boilers or just stand-alone bedside
alarms. Wall and mantlepiece clocks tend to be battery powered and so
are purely crystal based (although our wall clocks are good, old
clockwork).

I dont think most people undersatnd engineering cost, but them most
peole havent designed stuff to be mass produced and sold.

Most mains clocks are not run by synchronous motors now, they are LCD or
LED and controlled by a single chip. However, the mains is there and it
makes more sense to time from that (for the accuracy) and so they do.

A crystal costs next to nothing. Why would they use mains?It will end up
costing more


One of the big drivers for electric car windows is that a motor and
gearbox and switch is a little bit cheaper than a handle.

Is it? Fair enough, but why did we have many years with cars only having
electric windows as optional extras or only in the front?


Manufcturers stuck in teh age of te dinosaur/EU

Why do we have touch screens?Â* Menus? because they are cheaper than
proper controls.

Yes. Not just parts and production costs though. A big driver is that
software is easy and "cheap" to add new features to or to provide
different options for different trim levels of cars or levels of other
consumer goods.

Cost drives engineering development.

And in te comnsumert market, creeping featursim and novelty. Useless
features are added that dont cost anything more than a bit of
software, to make everything massively over complicated, which appeals
to low brow users.

I am perfectly happy to have lots of extra features, as long as they
don't get in the way of the basic, day-to-day operation - and too often
they do.

Exactly.

I simply cant be arsed to learn how to set a modern microwave fpr '3
mintes at half power please' when its all buttons and menus,

Its 1 second on two rotary dials here.

Commercial microwaves have knobs

The prize for the worst user interface in te workld gose to smart phones

I missed about 30 calls before I worked out how to answer it

What ever happened to 'lift handset and talk'


SteveW


--
Labour - a bunch of rich people convincing poor people to vote for rich
people
by telling poor people that "other" rich people are the reason they are
poor.

Peter Thompson