Mains power voltage drop to reduce usage?...

[Carlos E.R.]

On 2022-11-18 00:09, Bob F wrote:

On 11/17/2022 11:20 AM, Carlos E.R. wrote:
On 2022-11-17 20:03, Commander Kinsey wrote:
On Sun, 13 Nov 2022 10:48:31 -0000, The Natural Philosopher
tnp@invalid.invalid> wrote:

On 12/11/2022 21:22, Carlos E.R. wrote:
On 2022-11-12 15:17, Commander Kinsey wrote:
On Sat, 12 Nov 2022 13:39:00 -0000, Carlos E.R.
robin_listas@es.invalid> wrote:

On 2022-11-12 14:22, Commander Kinsey wrote:
On Fri, 11 Nov 2022 17:55:38 -0000, rick
rick_hughes@_remove_btconnect.com> wrote:

On 06/11/2022 14:23, Commander Kinsey wrote:
Instead of rolling blackouts when there\'s a power
shortage, why don\'t we just allow (or deliberately) the
voltage and frequency to drop? Wouldn\'t that make a lot
of devices use less?

It is a legal requirement to keep the frequency at 50Hz
over a set period. Therefore if it lags at any point they
have to increase to catch up.

This was a legal requirement due to mains clocks.

But you can drop it to 49 for a while then put it up to 51
when there\'s plenty power.

And do it in the entire Europe, simultaneously?

We\'re linked by DC, so no.

Wrong.

Yes, the European mainland grid whilst it is not all of Europe, is
synchronised. I believe Norway, the UK and Ireland, are definietly
totally  separate.

I thought there was a problem with capacitance sending AC a long
distance, hence DC to the UK?  Yet they\'re managing AC throughout
most of Europe?

There is a problem with capacitance and inductance sending high voltage
underground or undersea for significant distances, which DC doesn\'t have.


More power can be sent through above ground lines too with DC than with AC.

Yes, true. But in this case, the losses using AC per kilometre are much
lower, so the length at which DC becomes economical above ground is much
greater than under ground or under water.


It is simply a question of calculating all the costs and deciding which
one turns cheaper.


--
Cheers, Carlos.

 

[server]

On Thu, 17 Nov 2022 19:03:47 -0000, \"Commander Kinsey\"
<CK1@nospam.com> wrote:

On Sun, 13 Nov 2022 12:42:11 -0000, <upsidedown@downunder.com> wrote:

There us a good map of the various synchronous networks in Europe in
https://en.wikipedia.org/wiki/Synchronous_grid_of_Continental_Europe

It should be noted that some areas in North Africa is connected to
UCTE. Denmark is interesting, Jutland is in UCTE while the islands
are in the Nordic net.

The CIS (Russia etc) has an own synchronous network.
The situation in Ukraine is currently unclear.

That\'s just dust from the bombs, you\'ll get a good view tomorrow.

The network issue in Ukraine has been messy for years.

According to https://en.wikipedia.org/wiki/Ukrenergo
Ukraine was disconnected from the Russian/CIS net hours before the
Russian invasion.

In March, there is a limited connection to Central Europe.

 

[The Natural Philosopher]

On 18/11/2022 10:42, upsidedown@downunder.com wrote:

On Thu, 17 Nov 2022 19:03:47 -0000, \"Commander Kinsey\"
CK1@nospam.com> wrote:

On Sun, 13 Nov 2022 12:42:11 -0000, <upsidedown@downunder.com> wrote:

There us a good map of the various synchronous networks in Europe in
https://en.wikipedia.org/wiki/Synchronous_grid_of_Continental_Europe

It should be noted that some areas in North Africa is connected to
UCTE. Denmark is interesting, Jutland is in UCTE while the islands
are in the Nordic net.

The CIS (Russia etc) has an own synchronous network.
The situation in Ukraine is currently unclear.

That\'s just dust from the bombs, you\'ll get a good view tomorrow.

The network issue in Ukraine has been messy for years.

According to https://en.wikipedia.org/wiki/Ukrenergo
Ukraine was disconnected from the Russian/CIS net hours before the
Russian invasion.

In March, there is a limited connection to Central Europe.
I think there is in fact a connection now.

I read it somewhere - but lord knows where so call it \'unconfirmed\' for now.



--
To ban Christmas, simply give turkeys the vote.

 

[Martin Brown]

On 17/11/2022 19:28, Carlos E.R. wrote:

On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

--
Regards,
Martin Brown

 

[Martin Brown]

On 17/11/2022 19:30, Carlos E.R. wrote:

On 2022-11-14 03:09, Commander Kinsey wrote:
On Sun, 13 Nov 2022 11:47:06 -0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 12/11/2022 14:18, Commander Kinsey wrote:
On Sat, 12 Nov 2022 13:37:24 -0000, Carlos E.R.
robin_listas@es.invalid> wrote:

On 2022-11-12 14:11, Commander Kinsey wrote:
On Sat, 12 Nov 2022 13:05:02 -0000, John Walliker
jrwalliker@gmail.com
wrote:

On Saturday, 12 November 2022 at 12:08:20 UTC, Commander Kinsey
wrote:

Why would an invertor disconnect at lower frequency? It should be
able to match any frequency.

Its a regulatory requirement.

That is not an explanation.  There\'s no reason to disconnect.

It is to me... If I am the engineer designing or installing an
inverter,
I have to follow the law and regulations.

No, you\'re *supposed* to.

And a puny domestic inverter will die horribly if it stays on too long.

Anyway, that doesn\'t explain why the regulation is there.  Surely an
invertor is capable of producing a sine wave at any frequency?

The semiconductor electronics are certainly capable of that but the
transformer will saturate and then get hot ultimately catching fire if
the frequency drops too low. Some US kit built for 60Hz only would get
awfully hot on UK 50Hz mains. A cheap and nasty US brand of shavers sold
mostly at Xmas relied on a 60Hz mechanical resonance for good measure.

Japanese kit can pretty much always be relied upon to work on either 50
or 60Hz since roughly half of their country is on each frequency.

Then it must be possible to let it go way below 50Hz.  The
regulation\'s a bit daft if some can do it.

No, because existing equipment can not handle it. The regulation simply
takes into account that equipment, those design constraints, and tells
you not to drop the frequency.

I think they probably could increase the low frequency bound for
domestic and modest sized solar or wind farms not to drop off grid. It
is preferable to stress a few motors and transformers for a few minutes
when compared to the major cost of dropping large segments of load.

Otherwise you get the cascade failure mode that afflicted the UK after a
freak lightning strike took out a fairly small electric plant and caused
a cascade of failures that took down mains for London and much of England.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/836626/20191003_E3C_Interim_Report_into_GB_Power_Disruption.pdf

It didn\'t help that electric trains required an engineering reset before
they could be moved from where they ground to a halt when the mains went
down.

Sure, go to your own island and put your own rules, from scratch, then
talk.

There is scope to modify the rules a bit so that losing 0.5Hz in grid
frequency doesn\'t cause all local generation to drop off grid. Even in
this rather bad case the generating companies got back to nominal
conditions within 5 minutes but by then they had shed a lot of load.

--
Regards,
Martin Brown

 

[Carlos E.R.]

On 2022-11-18 12:26, Martin Brown wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

WOW!

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

I had no idea.

--
Cheers, Carlos.

 

[Peeler]

On Fri, 18 Nov 2022 12:42:17 +0200, upsidedown@downunder.com, another
mentally deficient, troll-feeding senile ASSHOLE, blathered:

The network issue in Ukraine has been messy for years.

According to https://en.wikipedia.org/wiki/Ukrenergo
Ukraine was disconnected from the Russian/CIS net hours before the
Russian invasion.

In March, there is a limited connection to Central Europe.

WTF has this sick shit got to do with the 3 ngs you keep crossposting it to,
you brain dead, troll-feeding senile ASSHOLE?

 

[John Larkin]

On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

 

[Martin Brown]

On 18/11/2022 14:54, John Larkin wrote:

On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

All the big new ones are state of the art converters by Toshiba I think.
More info here:

https://www.global.toshiba/ww/news/energy/2021/04/news-20210401-01.html

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

But I wouldn\'t put it past them to still have running some arcane
elctromechanical kit lovingly maintained by a national living treasure.

It always used to amuse me going into one particular world class
semiconductor plant that at the right time of year there would be a rice
farmer ploughing an adjacent field with two oxen and a classic plough.

--
Regards,
Martin Brown

 

[John Larkin]

On Fri, 18 Nov 2022 15:43:18 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 18/11/2022 14:54, John Larkin wrote:
On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

All the big new ones are state of the art converters by Toshiba I think.
More info here:

https://www.global.toshiba/ww/news/energy/2021/04/news-20210401-01.html

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

But I wouldn\'t put it past them to still have running some arcane
elctromechanical kit lovingly maintained by a national living treasure.

It always used to amuse me going into one particular world class
semiconductor plant that at the right time of year there would be a rice
farmer ploughing an adjacent field with two oxen and a classic plough.

I visited the HP minicomputer operation in Cupertino CA, well, long
ago. The offices had big tinted windows and outside there were people
on ladders picking oranges.

We went to the old mill in Maynard MA too. We picked PDP-11 over the
klunky HP 16-bit thing.

 

[Fredxx]

On 18/11/2022 14:54, John Larkin wrote:

On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I would expect 5/6 gearing to spin the motor/generators are the correct rpm.

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

I was only aware of SCRs hitting power conversion, DC/AC in the 80s?

 

[Scott Lurndal]

John Larkin <jlarkin@highlandSNIPMEtechnology.com> writes:

On Fri, 18 Nov 2022 15:43:18 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

I visited the HP minicomputer operation in Cupertino CA, well, long
ago. The offices had big tinted windows and outside there were people
on ladders picking oranges.

Are you sure it was Oranges? Plums or Cherries would have been far
more likely. Oranges grow much better further south.

 

[John Larkin]

On Fri, 18 Nov 2022 16:08:54 GMT, scott@slp53.sl.home (Scott Lurndal)
wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> writes:
On Fri, 18 Nov 2022 15:43:18 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

I visited the HP minicomputer operation in Cupertino CA, well, long
ago. The offices had big tinted windows and outside there were people
on ladders picking oranges.

Are you sure it was Oranges? Plums or Cherries would have been far
more likely. Oranges grow much better further south.

They said they were oranges and they sure looked like oranges.

Some types of oranges and lemons grow well here, even in San
Francisco, which is a lot colder than Cupertino.

The HP machine was basically a 16-bit PDP-8, a page-addressing machine
with a couple of accumulators. HP also created a really slow, klunky
hyper-CISC machine that wasn\'t successful. HP was stunningly
not-creative when it came to computers.

None of the minicomputer companies survived, sort of like none of the
tube or early semiconductor companies are still around, or at least
still in the device business.

Intel is running on inertia now.

 

[John Larkin]

On Fri, 18 Nov 2022 16:07:47 +0000, Fredxx <fredxx@spam.uk> wrote:

On 18/11/2022 14:54, John Larkin wrote:
On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I would expect 5/6 gearing to spin the motor/generators are the correct rpm.

Or have a different number of poles. But the converters are mostly
electronic now.

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

I was only aware of SCRs hitting power conversion, DC/AC in the 80s?

SCR based dc/ac converters were fun, when one SCR forgot to commute.

 

[Martin Brown]

On 18/11/2022 16:07, Fredxx wrote:

On 18/11/2022 14:54, John Larkin wrote:
On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I would expect 5/6 gearing to spin the motor/generators are the correct
rpm.

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

I was only aware of SCRs hitting power conversion, DC/AC in the 80s?

In commercial use (just) in Norway for Gotland Island by 1970. Prior to
that they were using mercury arc converters. MOre detail here

https://www.nsenergybusiness.com/features/featuremaking-light-of-hvdc-transmission-in-gotland/

And even more here:
https://core.ac.uk/download/pdf/328720724.pdf

I can vaguely recall Ferranti having some R&D on it.

--
Regards,
Martin Brown

 

[Scott Lurndal]

John Larkin <jlarkin@highlandSNIPMEtechnology.com> writes:

On Fri, 18 Nov 2022 16:08:54 GMT, scott@slp53.sl.home (Scott Lurndal)
wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> writes:
On Fri, 18 Nov 2022 15:43:18 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

I visited the HP minicomputer operation in Cupertino CA, well, long
ago. The offices had big tinted windows and outside there were people
on ladders picking oranges.

Are you sure it was Oranges? Plums or Cherries would have been far
more likely. Oranges grow much better further south.

They said they were oranges and they sure looked like oranges.

Some types of oranges and lemons grow well here, even in San
Francisco, which is a lot colder than Cupertino.

Yes, I have an orange tree in my back yard in San Jose. But,
it\'s not optimal conditions as it does drop below freezing a
few times each winter. Perhaps less so up the peninsula.

When I moved to Sunnyvale, there were still cherry orchards
west of el camino.

 

[Martin Brown]

On 18/11/2022 17:05, John Larkin wrote:

On Fri, 18 Nov 2022 16:08:54 GMT, scott@slp53.sl.home (Scott Lurndal)
wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> writes:

The HP machine was basically a 16-bit PDP-8, a page-addressing machine
with a couple of accumulators. HP also created a really slow, klunky
hyper-CISC machine that wasn\'t successful. HP was stunningly
not-creative when it came to computers.

HPIB interface was pretty good for scientific and engineering and their
HP200 computers using 68k were OK. IBM PC\'s were very rough by
comparison and their graphics truly abominable.

https://www.hpmuseum.net/exhibit.php?class=1&cat=1

NEC9801 was pretty cool! HPIB and up to 1120 × 750 graphics in up to 16
colours (or 256 if you had wads of cash). Monitors with that resolution
were ludicrously expensive back then. Our ARGS On the VAX was 512x512.

It was a long while before the 7220 was surpassed. I quite liked TI\'s
9918 video chip with support for hardware sprites also ahead of its time.

None of the minicomputer companies survived, sort of like none of the
tube or early semiconductor companies are still around, or at least
still in the device business.

Intel is running on inertia now.

Their latest chips are still pretty good given the architecture.
Pipeline stalls are much less frequent than they used to be.

sqrt on the i5-12600 somehow benchmarks faster than divide on mine!
(it must be a quirk of how the thing pipelines instructions)


--
Regards,
Martin Brown

 

[Fredxx]

On 18/11/2022 17:10, John Larkin wrote:

On Fri, 18 Nov 2022 16:07:47 +0000, Fredxx <fredxx@spam.uk> wrote:

On 18/11/2022 14:54, John Larkin wrote:
On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I would expect 5/6 gearing to spin the motor/generators are the correct rpm.

Or have a different number of poles. But the converters are mostly
electronic now.

The smallest number is counted in pole pairs. 1 pole-pair is 3,000rpm. 5
pole-pairs is 600rpm, for the other side to have 6 pole-pairs for
60/50Hz conversion.

The motor will be 5 times larger than a 50Hz single pole-pair running at
3,000 rpm. 6 times larger than one running at 3,600 rpm. I can\'t see the
economics working for using larger, less efficient and more expensive
low-speed machines.

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

I was only aware of SCRs hitting power conversion, DC/AC in the 80s?


SCR based dc/ac converters were fun, when one SCR forgot to commute.

When they worked they were very good. I recall a small self-commutating
converter in a TV. It was quite reliable.

 

[Fredxx]

On 18/11/2022 17:16, Martin Brown wrote:

On 18/11/2022 16:07, Fredxx wrote:
On 18/11/2022 14:54, John Larkin wrote:
On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I would expect 5/6 gearing to spin the motor/generators are the
correct rpm.

I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

I was only aware of SCRs hitting power conversion, DC/AC in the 80s?

In commercial use (just) in Norway for Gotland Island by 1970. Prior to
that they were using mercury arc converters. MOre detail here

https://www.nsenergybusiness.com/features/featuremaking-light-of-hvdc-transmission-in-gotland/

The article mentions IGBT, an entirely different beast, and far better
behaved than a SCR.

And even more here:
https://core.ac.uk/download/pdf/328720724.pdf

I can vaguely recall Ferranti having some R&D on it.

A better article for the case in point, it goes to show the differences
between SCRs and IGBTs.

 

[Jeroen Belleman]

On 2022-11-18 18:10, John Larkin wrote:

On Fri, 18 Nov 2022 16:07:47 +0000, Fredxx <fredxx@spam.uk> wrote:

On 18/11/2022 14:54, John Larkin wrote:
On Fri, 18 Nov 2022 11:26:01 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:28, Carlos E.R. wrote:
On 2022-11-13 12:47, Martin Brown wrote:

...

Japanese kit can pretty much always be relied upon to work on either
50 or 60Hz since roughly half of their country is on each frequency.

Oh? I had no idea of that. Different islands, perhaps?

No a split along the middle of the main island and a DC interlink
between them (which turned out not to be high enough capacity after the
Fukushima disaster took out so much plant on the NE Pacific coast).

www.kepco.co.jp/english/home/denki/01.html

The map of Japan is a bit erm.. schematic.

Kyoto went with Westinghouse US electric kit and Tokyo went with German
generating kit so that both were present. This schism persisted after
WWII when the country was occupied by (mostly) US and British forces.

More of the story here:
https://www.japanfs.org/en/news/archives/news_id030904.html

Yikes. I wonder if any of the converters are motor-generators.

I would expect 5/6 gearing to spin the motor/generators are the correct rpm.

Or have a different number of poles. But the converters are mostly
electronic now.


I have an ancient (1967) GE SCR manual, which is full of
still-interesting circuits, like a frequency changing cycloconverter.

I was only aware of SCRs hitting power conversion, DC/AC in the 80s?


SCR based dc/ac converters were fun, when one SCR forgot to commute.

I suppose its friends would remind it very quickly, probably in a
spectacular fashion. Peer pressure.

Jeroen Belleman