In article ,
James Wilkinson Sword wrote:
On Fri, 09 Mar 2018 18:52:45 -0000, Dave Plowman (News) wrote:

In article ,
James Wilkinson Sword wrote:
I just don't worry about burglars. If you want to, then own two cars.
Always leave one in the driveway. Way too risky to burgle a house with
a car present.

They'd just nick the car instead...

Too traceable, and insured anyway.

And just watch your premium go up if you claim for a stolen car.

Two neighbours have had cars stolen which disappeared without trace.
Probably taken abroad.

--
*El nino made me do it

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
James Wilkinson Sword wrote:
On Sat, 10 Mar 2018 00:22:08 -0000, Dave Plowman (News) wrote:

In article ,
James Wilkinson Sword wrote:
On Fri, 09 Mar 2018 18:52:45 -0000, Dave Plowman (News) wrote:

In article ,
James Wilkinson Sword wrote:
I just don't worry about burglars. If you want to, then own two cars.
Always leave one in the driveway. Way too risky to burgle a house with
a car present.

They'd just nick the car instead...

Too traceable, and insured anyway.

And just watch your premium go up if you claim for a stolen car.

Two neighbours have had cars stolen which disappeared without trace.
Probably taken abroad.

I don't know anyone who has ever had a car stolen. Move.

I had a colleague who had a car stolen. When it was recovered it was found
that the thieves had dropped some ball bearings into the carburettor. So
new engine needed.

--
from KT24 in Surrey, England

On 10/03/18 08:53, charles wrote:
In article ,
James Wilkinson Sword wrote:
On Sat, 10 Mar 2018 00:22:08 -0000, Dave Plowman (News) wrote:

In article ,
James Wilkinson Sword wrote:
On Fri, 09 Mar 2018 18:52:45 -0000, Dave Plowman (News) wrote:

In article ,
James Wilkinson Sword wrote:
I just don't worry about burglars. If you want to, then own two cars.
Always leave one in the driveway. Way too risky to burgle a house with
a car present.

They'd just nick the car instead...

Too traceable, and insured anyway.

And just watch your premium go up if you claim for a stolen car.

Two neighbours have had cars stolen which disappeared without trace.
Probably taken abroad.

I don't know anyone who has ever had a car stolen. Move.

I had a colleague who had a car stolen. When it was recovered it was found
that the thieves had dropped some ball bearings into the carburettor. So
new engine needed.


I have had two cars stolen.
And one attempted to be stolen.

Two in London, One in Brussels.

Got them all back, in various states.



--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

The Natural Philosopher wrote:

I thought electric trains connect(ed) their motors in parallel mode to
start off, which is why they always (used to) start with a jerk.

Series, more like, to limit current.

That's right, start in series, then later switch to parallel.

Jerk is just the inability to reduce it ENOUGH.

Quite so. Until the advent of power electronics in rail traction,
then control was generally either by tapchanger, for ac supplies,
or series resistors for dc schemes. In both cases the steps (or
notches as they are known) are finite, not continuously variable,
and there will always be jerks. The art of the design engineer is
making them as smooth as practicable.

Somewhere in the loft I have the notching curves I drew for the
Class 313 rolling stock.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

charles wrote:


I had a colleague who had a car stolen. When it was recovered it was found
that the thieves had dropped some ball bearings into the carburettor. So
new engine needed.


Weird. What kind of car thief carries ball bearings with them? There seems
to be a more plausible explanation to me...

Tim

--
Please don't feed the trolls

Chris J Dixon wrote:

Until the advent of power electronics in rail traction, then control
was generally either by tapchanger, for ac supplies, or series
resistors for dc schemes. In both cases the steps (or notches as they
are known) are finite, not continuously variable, and there will
always be jerks.

On more recent trains, I seem to hear the electronics "whistling" a set
of steps as they depart, why not continuous?

Or are those just more noticeable and the latest ones /are/ continuous?

On Friday, 9 March 2018 10:15:38 UTC, Andrew Gabriel wrote:
In article ,
Max Demian writes:
On 08/03/2018 23:14, Marland wrote:
Andrew Gabriel

Before the Berlin wall came down, there were two continental Europe
synchronisation zones, Western Europe run from Switzerland, and
Eastern Europe run from Moscow. The first was +/- 0.1Hz, the second
was +/- 1Hz, IIRC. The western side was actually very short on spare
capacity (particularly Germany), and the east had lots, but from
highly poluting sources. When the wall came down, Germany was in a
dilema at the time on using power from the east which Western German
industry desperately needed, but seriously pumping up the resulting

Germany and Austria also have a separate grid to distribute power for their
railways,due to the electrification commencing in the 1900s and the
characteristics of motors of the era a low frequency of 16 and two thirds
was adopted. This low frequency is also used in Switzerland and Scandinavia
but they tend to generate from nearby hydro or convert from the 50hz grid
where required.

They must have 'normous transformers.

3 times the size, and they have to be carried by the train.

However, they couldn't make large powerful motors which ran on 50Hz
at the time, because the winding inductance would be too high to
get the necessary power in without the windings having to operate
at voltages which winding insulation couldn't withstand.

Yes they could. Over a hundred years ago.
Just expensive.
https://www.youtube.com/watch?v=_Q0N6m55bHg

On Sat, 10 Mar 2018 00:22:08 +0000 (GMT), Dave Plowman (News) wrote:

And just watch your premium go up if you claim for a stolen car.

Two neighbours have had cars stolen which disappeared without trace.
Probably taken abroad.

Idiot!

On Sat, 10 Mar 2018 08:53:09 +0000 (GMT), charles wrote:

I had a colleague who had a car stolen.

YOU had your brain stolen, ****head!

In article
, Tim+
wrote:
charles wrote:


I had a colleague who had a car stolen. When it was recovered it was
found that the thieves had dropped some ball bearings into the
carburettor. So new engine needed.


Weird. What kind of car thief carries ball bearings with them? There
seems to be a more plausible explanation to me...


which is? BTW the owner of thatbcar died about 20 years ago.

--
from KT24 in Surrey, England

In article ,
James Wilkinson Sword wrote:
Two neighbours have had cars stolen which disappeared without trace.
Probably taken abroad.

I don't know anyone who has ever had a car stolen. Move.

Of course not. Who would steal the sort of cars found in your area. Apart
from a desperate joy rider.

--
*The modem is the message *

Dave Plowman London SW
To e-mail, change noise into sound.

charles wrote:
In article
, Tim+
wrote:
charles wrote:


I had a colleague who had a car stolen. When it was recovered it was
found that the thieves had dropped some ball bearings into the
carburettor. So new engine needed.


Weird. What kind of car thief carries ball bearings with them? There
seems to be a more plausible explanation to me...


which is? BTW the owner of thatbcar died about 20 years ago.


That the owner knew that the engine was already a bit shagged and dropped
them in himself...

Of course theres no way of knowing but it seems more plausible than car
thieving scrotes carrying ball bearings so that they can maliciously wreck
an engine of a vehicle that they plan to dump.

Tim

--
Please don't feed the trolls

On 10/03/2018 12:56, Tim+ wrote:
charles wrote:
In article
, Tim+
wrote:
charles wrote:


I had a colleague who had a car stolen. When it was recovered it was
found that the thieves had dropped some ball bearings into the
carburettor. So new engine needed.


Weird. What kind of car thief carries ball bearings with them? There
seems to be a more plausible explanation to me...


which is? BTW the owner of thatbcar died about 20 years ago.


That the owner knew that the engine was already a bit shagged and dropped
them in himself...

Of course theres no way of knowing but it seems more plausible than car
thieving scrotes carrying ball bearings so that they can maliciously wreck
an engine of a vehicle that they plan to dump.

That was my thought too. Why take the trouble to open a bonnet and
remove filter housing etc.

These days it would be torched to remove DNA evidence.

In article ,
James Wilkinson Sword wrote:
Of course not. Who would steal the sort of cars found in your area.
Apart from a desperate joy rider.

Only old cars get stolen, stealing a new car is too problematic.

Shows how much you know. Both vehicles stolen and not recovered near here
were new and very expensive.

--
*Change is inevitable, except from a vending machine.

Dave Plowman London SW
To e-mail, change noise into sound.

On 10/03/2018 12:56, Tim+ wrote:
charles wrote:
In article
, Tim+
wrote:
charles wrote:


I had a colleague who had a car stolen. When it was recovered it was
found that the thieves had dropped some ball bearings into the
carburettor. So new engine needed.


Weird. What kind of car thief carries ball bearings with them? There
seems to be a more plausible explanation to me...


which is? BTW the owner of thatbcar died about 20 years ago.


That the owner knew that the engine was already a bit shagged and dropped
them in himself...

Of course theres no way of knowing but it seems more plausible than car
thieving scrotes carrying ball bearings so that they can maliciously wreck
an engine of a vehicle that they plan to dump.

Tim


And take the tools to get to the intake and past the filter.

On Sat, 10 Mar 2018 14:40:48 +0000 (GMT), Dave Lowman (News) wrote:

Only old cars get stolen, stealing a new car is too problematic.

Shows how much you know. Both vehicles stolen and not recovered near here
were new and very expensive.

Serves you right, you troll-feeding idiot!

James Wilkinson Sword wrote:

I wish someone would put soft start onto conveyor belts in supermarkets.
Actually it is kinda funny to put milk or bottles of vodka upright then
laugh when the supermarket has to replace them for free.

In France they actually have a little sign asking you to lay bottles
down on the belt.

--
Chris Green
·

James Wilkinson Sword wrote:

On Sat, 10 Mar 2018 09:36:36 -0000, Chris J Dixon wrote:

The Natural Philosopher wrote:

I thought electric trains connect(ed) their motors in parallel mode to
start off, which is why they always (used to) start with a jerk.

Series, more like, to limit current.

That's right, start in series, then later switch to parallel.

Jerk is just the inability to reduce it ENOUGH.

Quite so. Until the advent of power electronics in rail traction,
then control was generally either by tapchanger, for ac supplies,
or series resistors for dc schemes. In both cases the steps (or
notches as they are known) are finite, not continuously variable,
and there will always be jerks. The art of the design engineer is
making them as smooth as practicable.

Somewhere in the loft I have the notching curves I drew for the
Class 313 rolling stock.

I wish someone would put soft start onto conveyor belts in supermarkets.
Actually it is kinda funny to put milk or bottles of vodka upright then
laugh when the supermarket has to replace them for free.


I expect they sometimes wish the mentally subnormal had minders to tell
them to put glass bottles on their sides.

--

Roger Hayter

Chris Green wrote:

James Wilkinson Sword wrote:

I wish someone would put soft start onto conveyor belts in supermarkets.
Actually it is kinda funny to put milk or bottles of vodka upright then
laugh when the supermarket has to replace them for free.

In France they actually have a little sign asking you to lay bottles
down on the belt.

In the UK we don't generally need to point it out.

--

Roger Hayter

On Saturday, 10 March 2018 19:50:23 UTC, James Wilkinson Sword wrote:
On Sat, 10 Mar 2018 00:22:08 -0000, Dave Plowman (News) wrote:

And just watch your premium go up if you claim for a stolen car.

Your premium is supposed to be linked to accidents (or otherwise) that are YOUR fault. That's why when you take out insurance they ask how many accidents you've had in the last 5 years that YOU caused.

wrong again

On Sat, 10 Mar 2018 21:01:10 +0000, Roger Hayter wrote:

I wish someone would put soft start onto conveyor belts in supermarkets.
Actually it is kinda funny to put milk or bottles of vodka upright then
laugh when the supermarket has to replace them for free.

I expect they sometimes wish the mentally subnormal had minders to tell
them to put glass bottles on their sides.

Troll-feeding idiot!

On Sat, 10 Mar 2018 20:47:14 +0000, Chris Green wrote:

In France they actually have a little sign asking you to lay bottles
down on the belt.

Troll-feeding idiot!

Peeler wrote:

On Sat, 10 Mar 2018 20:47:14 +0000, Chris Green wrote:

In France they actually have a little sign asking you to lay bottles
down on the belt.

Troll-feeding idiot!

We're quite entitled to feed the trolls if we want to. This isn't a
zoo, you know!

--

Roger Hayter

On Sat, 10 Mar 2018 20:47:14 +0000, Chris Green wrote:

James Wilkinson Sword wrote:

I wish someone would put soft start onto conveyor belts in
supermarkets.
Actually it is kinda funny to put milk or bottles of vodka upright then
laugh when the supermarket has to replace them for free.

In France they actually have a little sign asking you to lay bottles
down on the belt.

And in the UK.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 10/03/2018 22:42, Bob Eager wrote:
On Sat, 10 Mar 2018 20:47:14 +0000, Chris Green wrote:

James Wilkinson Sword wrote:

I wish someone would put soft start onto conveyor belts in
supermarkets.
Actually it is kinda funny to put milk or bottles of vodka upright then
laugh when the supermarket has to replace them for free.

In France they actually have a little sign asking you to lay bottles
down on the belt.

And in the UK.

The trouble is that if you are shopping for a party and have a number of
bottles, plus food, laying the bottles down means that the belt ends up
full and you can't fit all of your shopping on, yet you need to be at
the other end packing things away!

SteveW

On Sat, 10 Mar 2018 22:03:02 +0000, Roger Hayter wrote:


In France they actually have a little sign asking you to lay bottles
down on the belt.

Troll-feeding idiot!

We're quite entitled to feed the trolls if we want to.

Idiots are ...by right of their idiocy.

In article ,
Steve Walker wrote:
The trouble is that if you are shopping for a party and have a number of
bottles, plus food, laying the bottles down means that the belt ends up
full and you can't fit all of your shopping on, yet you need to be at
the other end packing things away!

If you pack things tight on the belt, the bottles won't fall over.

--
*Women who seek to be equal to men lack ambition.

Dave Plowman London SW
To e-mail, change noise into sound.

On 11/03/2018 00:10, Dave Plowman (News) wrote:
In article ,
Steve Walker wrote:
The trouble is that if you are shopping for a party and have a number of
bottles, plus food, laying the bottles down means that the belt ends up
full and you can't fit all of your shopping on, yet you need to be at
the other end packing things away!

If you pack things tight on the belt, the bottles won't fall over.

I know. That's why I ignore the signs to lay the bottles flat

SteveW

Peeler wrote:

On Sat, 10 Mar 2018 22:03:02 +0000, Roger Hayter wrote:


In France they actually have a little sign asking you to lay bottles
down on the belt.

Troll-feeding idiot!

We're quite entitled to feed the trolls if we want to.

Idiots are ...by right of their idiocy.

I shall wear the badge with pride. Do you think you might be obsessed?

--

Roger Hayter

Andy Burns wrote:

Chris J Dixon wrote:

Until the advent of power electronics in rail traction, then control
was generally either by tapchanger, for ac supplies, or series
resistors for dc schemes. In both cases the steps (or notches as they
are known) are finite, not continuously variable, and there will
always be jerks.

On more recent trains, I seem to hear the electronics "whistling" a set
of steps as they depart, why not continuous?

Or are those just more noticeable and the latest ones /are/ continuous?

I can't give you chapter and verse, but I think you are about
right there.

If you want to delve a little deeper into the whole subject, this
can be a good starting point.

http://www.railway-technical.com/trains/rolling-stock-index-l/train-equipment/electric-traction-control-d.html

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On Fri, 09 Mar 2018 10:52:20 +0000, Dave Plowman (News) wrote:

In article ,
Johnny B Good wrote:
Presumably, this change was implemented early on in readiness for
colour transmissions, perhaps to ease the final transition to a system
that could no longer be locked to the mains frequency.

It may have been to do with the increasing use of outside broadcasts
and
so on as inserts to programmes. Think things like Nationwide. Where
those might use their own generator or battery supply. You could lock
the studio to a pulse generator anywhere, allowing pictures to be mixed
between the two. Terms like genlock and natlock were bandied about at
the time. And of course a VTR needs a stable 50 Hz reference too. Which
mains simply isn't.

If a VTR is locked to mains, its playing time will vary with that mains
frequency. Not exactly ideal.

Aha! An excellent reason to bow to the inevitable then. :-)


--
Johnny B Good

"Andrew Gabriel" wrote in message
news
In article ,
Max Demian writes:
On 08/03/2018 23:14, Marland wrote:
Andrew Gabriel

Before the Berlin wall came down, there were two continental Europe
synchronisation zones, Western Europe run from Switzerland, and
Eastern Europe run from Moscow. The first was +/- 0.1Hz, the second
was +/- 1Hz, IIRC. The western side was actually very short on spare
capacity (particularly Germany), and the east had lots, but from
highly poluting sources. When the wall came down, Germany was in a
dilema at the time on using power from the east which Western German
industry desperately needed, but seriously pumping up the resulting

What were the reasons for the UK having its own grid, with a *DC* connection
to mainland Europe? Was it just that the UK wasn't part of Europe at the
time, or was there another more technical, less political reason?

On Tuesday, 13 March 2018 12:13:53 UTC, NY wrote:
"Andrew Gabriel" wrote in message
news
In article ,
Max Demian writes:
On 08/03/2018 23:14, Marland wrote:
Andrew Gabriel

Before the Berlin wall came down, there were two continental Europe
synchronisation zones, Western Europe run from Switzerland, and
Eastern Europe run from Moscow. The first was +/- 0.1Hz, the second
was +/- 1Hz, IIRC. The western side was actually very short on spare
capacity (particularly Germany), and the east had lots, but from
highly poluting sources. When the wall came down, Germany was in a
dilema at the time on using power from the east which Western German
industry desperately needed, but seriously pumping up the resulting

What were the reasons for the UK having its own grid, with a *DC* connection
to mainland Europe? Was it just that the UK wasn't part of Europe at the
time, or was there another more technical, less political reason?

There is a maximum size for synchronised ac distribution areas.
There may also be security issues.


NT

On 13/03/18 12:13, NY wrote:
"Andrew Gabriel" wrote in message
news
In article ,
Max Demian writes:
On 08/03/2018 23:14, Marland wrote:
Andrew Gabriel

Before the Berlin wall came down, there were two continental Europe
synchronisation zones, Western Europe run from Switzerland, and
Eastern Europe run from Moscow. The first was +/- 0.1Hz, the second
was +/- 1Hz, IIRC. The western side was actually very short on spare
capacity (particularly Germany), and the east had lots, but from
highly poluting sources. When the wall came down, Germany was in a
dilema at the time on using power from the east which Western German
industry desperately needed, but seriously pumping up the resulting

What were the reasons for the UK having its own grid, with a *DC*
connection to mainland Europe? Was it just that the UK wasn't part of
Europe at the time, or was there another more technical, less political
reason?

Well you see its this odd and not very political thing called GEOGRAPHY.
You maye have heard of it although its not as fashoinable as gay
marriage, but what it means is that if you walked all round the COAST
like that ponce on TV you find that is water on every side!

And that means its a long way to string pylons in shipping lanes so teh
GB grid is naturally isolated and always was, since ints inception in
IIRC the 1930s


Really it wwsnt much point in building any undersea links until the 60s,
as AC links were too lossy and the electronics to do DC links was still
pretty impressively huge featuring mercury arc valves and the like.

Later on with silicon stuff it got a bit easier. And access to cheap
French nuclear power was an economic driver.


You see, I know its hard to understand, but EU treaties do not join
countries together. Bridges and roads and cables and tunnels and ferries
do, no matter what some **** in Brussels thinks or says.

I know its hard stuff, this 'thinking' but if you do a bit more of it
you will realise that life goes on without any politics at all.

Out in my garden Pigeons are having sex and building nests *without any
legal status or rights as couples or as parents*.

WOW!

Similarly electrons are flowing dutifully down wires everywhere
irrespective of any human prescribed laws or statutes.

Apparently - I watched the documentary - the ancient Olmecs and Toltecs
and Mayans of Mexico all thought they could control the climate by
worshipping the right gods and sacrificing the odd victim.

They all died, because they couldn't.

Are you listening Mr. Attenborough?

--
Climate Change: Socialism wearing a lab coat.

On 13/03/18 12:26, wrote:
There is a maximum size for synchronised ac distribution areas.

No, there is a size beyond which efficiency drops. Due to propagation delay.

There may also be security issues.

There are not.

But as usual you have missed the real poinst. Ther is no reason to sunch
the GB grid with Europe because its NOT CONNECTED. Except by DC links.
Its a different marter where Germany and te former Eastern Bloc are
concerned - stringing some AC pylons over a border is easy...until
politics rears its head.




--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

"The Natural Philosopher" wrote in message
news
On 13/03/18 12:13, NY wrote:
What were the reasons for the UK having its own grid, with a *DC*
connection to mainland Europe? Was it just that the UK wasn't part of
Europe at the time, or was there another more technical, less political
reason?

Well you see its this odd and not very political thing called GEOGRAPHY.
You maye have heard of it although its not as fashoinable as gay marriage,
but what it means is that if you walked all round the COAST like that
ponce on TV you find that is water on every side!

And that means its a long way to string pylons in shipping lanes so teh GB
grid is naturally isolated and always was, since ints inception in IIRC
the 1930s

Yes, that's a very good reason for not having *any* connection between UK
and mainland Europe. But given that there *is* a connection, is there a
reason why it is DC rather than AC? People have mentioned propagation delay?
How does the north-south length of the UK compare with the length and width
of the linked parts of mainland Europe?

Presumably if power is to be exported/imported over the DC link, there needs
to be a means of converting the DC back to AC at the correct frequency and
phase - probably at one time this would have involved rotary converters (DC
motor driving AC generator). Wouldn't this cause greater losses than in
transformers of an AC link? And the system needs to be reversible so energy
can be sent in either direction according to who has a surplus at any
instant.

"Tim Streater" wrote in message
.. .
In article , NY
wrote:

"The Natural Philosopher" wrote in message
news
On 13/03/18 12:13, NY wrote:
What were the reasons for the UK having its own grid, with a *DC*
connection to mainland Europe? Was it just that the UK wasn't part of
Europe at the time, or was there another more technical, less political
reason?

Well you see its this odd and not very political thing called GEOGRAPHY.
You maye have heard of it although its not as fashoinable as gay
marriage, but what it means is that if you walked all round the COAST
like that ponce on TV you find that is water on every side!

And that means its a long way to string pylons in shipping lanes so teh
GB grid is naturally isolated and always was, since ints inception in
IIRC the 1930s

Yes, that's a very good reason for not having *any* connection between UK
and mainland Europe.

No, you run it on the seabed, or perhaps through the tunnel.

But given that there *is* a connection, is there a reason why it is DC
rather than AC?

Capacitance losses.

Ah. Yes that makes sense. 20 miles of overhead line would be fine (*) but 20
miles of coaxial cable will have significant capacitance.

As a matter of interest, how do they avoid the problem when overhead lines
are converted to run underground, eg when passing through an area of
outstanding natural beauty?

Do underground lines run as a single cable with three conductors (for three
phases) surrounded by a common earth, or are they three separate lines, each
with its own earth screen? Indeed is it necessary to have an earth screen as
long as the wires are suitably insulated?



(*) Apart from the "little" matter of suspending the wires across the
Channel :-)

On Tuesday, 13 March 2018 13:01:41 UTC, The Natural Philosopher wrote:
On 13/03/18 12:26, tabbypurr wrote:

There is a maximum size for synchronised ac distribution areas.

No, there is a size beyond which efficiency drops. Due to propagation delay.

there are both

There may also be security issues.

There are not.

But as usual you have missed the real poinst. Ther is no reason to sunch
the GB grid with Europe because its NOT CONNECTED. Except by DC links.

No I haven't missed that point. Any more junk you'd like to make up?

Its a different marter where Germany and te former Eastern Bloc are
concerned - stringing some AC pylons over a border is easy...until
politics rears its head.

so you admit politics is an issue after all. Well done.


NT

On 13/03/18 15:26, NY wrote:
"The Natural Philosopher" wrote in message
news
On 13/03/18 12:13, NY wrote:
What were the reasons for the UK having its own grid, with a *DC*
connection to mainland Europe? Was it just that the UK wasn't part of
Europe at the time, or was there another more technical, less
political reason?

Well you see its this odd and not very political thing called
GEOGRAPHY. You maye have heard of it although its not as fashoinable
as gay marriage, but what it means is that if you walked all round the
COAST like that ponce on TV you find that is water on every side!

And that means its a long way to string pylons in shipping lanes so
teh GB grid is naturally isolated and always was, since ints inception
in IIRC the 1930s

Yes, that's a very good reason for not having *any* connection between
UK and mainland Europe. But given that there *is* a connection, is there
a reason why it is DC rather than AC?

Efficiency.



People have mentioned propagation
delay? How does the north-south length of the UK compare with the length
and width of the linked parts of mainland Europe?

small. Its about 600 miles tip to tip. USA is split into 1000 mile sizes



Presumably if power is to be exported/imported over the DC link, there
needs to be a means of converting the DC back to AC at the correct
frequency and phase - probably at one time this would have involved
rotary converters (DC motor driving AC generator).

No. It never did.

Always done with choppers.

Originally mercury arc

https://en.wikipedia.org/wiki/Mercury-arc_valve

I visted te first cross cvhannel link in the mid 1960s.

https://en.wikipedia.org/wiki/HVDC_C...W_system_(1961)

The valbesd were impressibe BUT the most ompressive thing was the acre
or so of hsehd sized chokes and capacitors smoothing out the chop!

The whole site sounded like a digeridoo, and since we wher scvhoolbotys,
'Sun arise, come with de morning' was soon echoing around..

https://www.youtube.com/watch?v=0XOO0I8ZsIk


Wouldn't this cause
greater losses than in transformers of an AC link?

Yes, but that is completely dwarfed by the savinhgs in losses in the
cable itself.

And the system needs
to be reversible so energy can be sent in either direction according to
who has a surplus at any instant.

Yes, sometimes that breaks and it's one way only :-)


--
€œBut what a weak barrier is truth when it stands in the way of an
hypothesis!€�

Mary Wollstonecraft

On 13/03/18 15:39, Tim Streater wrote:
In article , NY
wrote:

"The Natural Philosopher" wrote in message
news
On 13/03/18 12:13, NY wrote:
What were the reasons for the UK having its own grid, with a *DC*
connection to mainland Europe? Was it just that the UK wasn't part
of Europe at the time, or was there another more technical, less
political reason?

Well you see its this odd and not very political thing called
GEOGRAPHY. You maye have heard of it although its not as fashoinable
as gay marriage, but what it means is that if you walked all round
the COAST like that ponce on TV you find that is water on every side!

And that means its a long way to string pylons in shipping lanes so
teh GB grid is naturally isolated and always was, since ints
inception in IIRC the 1930s

Yes, that's a very good reason for not having *any* connection between
UK and mainland Europe.

No, you run it on the seabed, or perhaps through the tunnel.

But given that there *is* a connection, is there a reason why it is DC
rather than AC?

Capacitance losses.

Strictly the losses are resistive, caused by capacitance.



--
€œit should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalins Communist era, nor in the Orwellian
utopia of 1984.€�

Vaclav Klaus