I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

Gary

On Tue, 13 Dec 2011 23:50:27 +0000, Gary
wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

All the smoke that is trapped in the wires would come out, there may
be extreme acoustic events, and photons would strike your eyes.

--

Gary wrote:
I was wondering what would happen if you connected a working generator
to the mains whilst power was on.


****ing big bang unless you are EXTREMELY lucky and the thing is in phase.

I am asuming it would not be a good thing?? anybody actually know what
happens?


See above..
Gary

The Other Mike wrote:
On Tue, 13 Dec 2011 23:50:27 +0000, Gary
wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

All the smoke that is trapped in the wires would come out, there may
be extreme acoustic events, and photons would strike your eyes.

= a ****ing big bang.

On 13 Dec,
Gary wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

Depends. If it's nearly in phase and roughly the right speed it will
synchronise. (I've done it many times). If out of phase BNAG!!!

In the late 70s we were no longer allowed to synchronise to the mains for two
reasons.

1, Someone had done it out of phase and BNAG!!!!.

2, It's not nice to have mains back fed onto an otherwise dead supply. You
then might get dead electricity board employees as well, and they don't like
it uppem! to use a Clive Dunn expression.

--
B Thumbs
Change lycos to yahoo to reply

Erm, if you don't synchonise the frequency, it would not be good, and
probably illegal.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Gary" wrote in message
...
I was wondering what would happen if you connected a working generator to
the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

Gary

So if you run a chip shop and use the old oil in a dc generator, and use the
dc to power one of the invertors that solar uses, then connected it to th4e
mains, could you get the money for the units?
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"The Natural Philosopher" wrote in message
...
The Other Mike wrote:
On Tue, 13 Dec 2011 23:50:27 +0000, Gary
wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

All the smoke that is trapped in the wires would come out, there may
be extreme acoustic events, and photons would strike your eyes.

= a ****ing big bang.

Brian Gaff wrote:
So if you run a chip shop and use the old oil in a dc generator, and use the
dc to power one of the invertors that solar uses, then connected it to th4e
mains, could you get the money for the units?
Brian

No

Brian Gaff wrote:
So if you run a chip shop and use the old oil in a dc generator, and use the
dc to power one of the invertors that solar uses, then connected it to th4e
mains, could you get the money for the units?

sure.


Brian

On Dec 14, 5:37*am, "Brian Gaff" wrote:
So if you run a chip shop and use the old oil in a dc generator, and use the
dc to power one of the invertors that solar uses, then connected it to th4e
mains, could you get the *money for the units?
*Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
*graphics are great, but the blind can't hear them
Email:
__________________________________________________ _________________________*________________________ ___________

"The Natural Philosopher" wrote in ...



The Other Mike wrote:
On Tue, 13 Dec 2011 23:50:27 +0000, Gary
wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

Not legally at the moment.
http://www.claverton-energy.com/the-...directive.html
However. technically feasible (but not with the generatoryou have) and
may be in the pipeline for domestic use.
Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

Regards,
Martin Brown

In article , scribeth
thus
On 13 Dec,
Gary wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

Depends. If it's nearly in phase and roughly the right speed it will
synchronise. (I've done it many times). If out of phase BNAG!!!

In the late 70s we were no longer allowed to synchronise to the mains for two
reasons.

1, Someone had done it out of phase and BNAG!!!!.

Umm ... don't they have fuses? .......


2, It's not nice to have mains back fed onto an otherwise dead supply. You
then might get dead electricity board employees as well, and they don't like
it uppem! to use a Clive Dunn expression.


--
Tony Sayer

On Dec 14, 10:28*am, tony sayer wrote:
In article , scribeth
thus





On 13 Dec,
* * Gary wrote:

I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

Depends. If it's nearly in phase and roughly the right speed it will
synchronise. (I've done it many times). If out of phase BNAG!!!

In the late 70s we were no longer allowed to synchronise to the mains for two
reasons.

1, Someone had done it out of phase and BNAG!!!!.

Umm ... don't they have fuses? .......



2, It's not nice to have mains back fed onto an otherwise dead supply. You
then might get dead electricity board employees as well, and they don't like
it uppem! *to use a Clive Dunn expression.

--
Tony Sayer- Hide quoted text -

- Show quoted text -

Can be taken care of.
http://en.wikipedia.org/wiki/Anti-islanding

On Dec 14, 9:59*am, Martin Brown
wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run *in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

As were PV panels at one time.
I often wonder if thermopiles might be a better alternative to PV
panels.

In message , Gary
writes
I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

I have actually done this (at university, in 1963). It was a pretty
large three-phase generator (the size of a small car), and the object of
the exercise was to connect it to the three-phase mains. The generator
was driven by a DC motor.

Before connecting the generator to the mains, I had to adjust the speed
of the DC motor so that the generator was driven up to synchronous speed
and the correct phase angle (ie each phase of the generator was looking
at the correct phase of the mains). The generator DC field current was
then adjusted to that there was minimal voltage difference between the
generator and the mains.

When I was satisfied, and making sure that my fingers were well and
truly crossed, I then threw a big knife switch which connected the
generator to the mains.

I then increased the field current so that the generator started
generating (ie current started to flow into the mains). At the same
time, I had to adjust the field current of the DC motor so that its
power output to the drive shaft of the generator also increased
(otherwise the generator would have started to lack power, and become a
motor).

The experiment then continued with me monitoring and plotting on graphs
all the relevant currents and voltages while the generator was behaving
as both a generator and a synchronous motor. I recall that, in one
condition, the generator can be made to behave as a capacitor to the
mains feed, and this used to be one method of providing variable amounts
power factor correction.

BTW, don't try this at home! ;o))
--
Ian

--- Posted via news://freenews.netfront.net/ - Complaints to ---

On Dec 14, 11:02*am, harry wrote:
I often wonder if thermopiles might be a better alternative to PV
panels.

Geothermal all over wales, mendips etc, would be fine in the UK.

On 14/12/2011 11:02, harry wrote:
On Dec 14, 9:59 am, Martin
wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

As were PV panels at one time.
I often wonder if thermopiles might be a better alternative to PV
panels.

You have to be kidding. You can have affordable or efficient thermopiles
but not both at the same time. It is very niche market.

I tried to put together a candle powered demo for an Xmas lecture using
them (fairly high grade units). I was intending to drive one puny LED
from the waste heat of a candle flame (about 100W).

I had a high temperature TEC module and a boring one stacked and even
operating it between 250C hot side to a large deep frozen heatsink -18C
on the cold side I could barely get enough juice out to do anything
useful. I decided that at these temperatures it was too hazardous for a
childrens' Xmas science lecture and scrapped the idea.

The same TEC units can move 50W or so from the hot plate to the cold
plate when suitably powered. But try to generate power with them with a
temperature difference applied and it is a lot less efficient. I would
be interested to know if anyone has found a setup that works - ideally
enough to power a 1W led (but I'd settle for 10mA and 4v).

Previous toys have included candle powered nodding heat engine and a
heat engine that on a good day will run off a cup of fresh coffee.

Regards,
Martin Brown

On Wed, 14 Dec 2011 11:25:36 +0000, Ian Jackson
wrote:

In message , Gary
writes
I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

I have actually done this (at university, in 1963). It was a pretty
large three-phase generator (the size of a small car), and the object of
the exercise was to connect it to the three-phase mains. The generator
was driven by a DC motor.

Before connecting the generator to the mains, I had to adjust the speed
of the DC motor so that the generator was driven up to synchronous speed
and the correct phase angle (ie each phase of the generator was looking
at the correct phase of the mains). The generator DC field current was
then adjusted to that there was minimal voltage difference between the
generator and the mains.

When I was satisfied, and making sure that my fingers were well and
truly crossed, I then threw a big knife switch which connected the
generator to the mains.

I then increased the field current so that the generator started
generating (ie current started to flow into the mains). At the same
time, I had to adjust the field current of the DC motor so that its
power output to the drive shaft of the generator also increased
(otherwise the generator would have started to lack power, and become a
motor).

The experiment then continued with me monitoring and plotting on graphs
all the relevant currents and voltages while the generator was behaving
as both a generator and a synchronous motor. I recall that, in one
condition, the generator can be made to behave as a capacitor to the
mains feed, and this used to be one method of providing variable amounts
power factor correction.

BTW, don't try this at home! ;o))

Fifty years on you've been replaced with a box of tricks costing a few
thousand quid that does it all for you and gets the breaker operation
point spot, including allowance for the mechanical operation of the
contacts, to ensure no damage to the circuit breaker or the generator.

In years gone by - well until the early 80's in the UK on small
generators they used an incandescent lamp connected between the
voltage transformers situated either side of the circuit breaker and
tweaked the generator excitation to produce minimum brightness in the
lamp to ensure the generator was in phase with the grid system before
breaker closure.

They also, and more commonly, used a lamp as above and a synchroscope.

http://en.wikipedia.org/wiki/Synchroscope


--

In message , The Other Mike
writes



In years gone by - well until the early 80's in the UK on small
generators they used an incandescent lamp connected between the
voltage transformers situated either side of the circuit breaker and
tweaked the generator excitation to produce minimum brightness in the
lamp to ensure the generator was in phase with the grid system before
breaker closure.

Surely you tuned the generator for a steady MINIMUM (ideally zero)
brightness?

They also, and more commonly, used a lamp as above and a synchroscope.

http://en.wikipedia.org/wiki/Synchroscope

Such sophistication! When I were I lad, we did it the 'ard way. The
university lecturers were 'ard - 'ard, but fair.
--
Ian

--- Posted via news://freenews.netfront.net/ - Complaints to ---

In article ,
harry writes:
On Dec 14, 9:59*am, Martin Brown
wrote:

Thermopiles are only really cost effective for space flight.
As were PV panels at one time.
I often wonder if thermopiles might be a better alternative to PV
panels.

They're even less efficient, but on a spacecraft, they are usually
driven by a nuclear reactor, which might present a few problems for
home generation. You can pick up many abandoned ones from around
the northern coasts of the former USSR, where they were used as
things like lighthouse power generators. Most of the people who
have tried recovering one of these, enticed by the idea of 1-2kW
of free power for years, have died very shortly afterwards though.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Wed, 14 Dec 2011 13:06:37 +0000, Ian Jackson
wrote:

In message , The Other Mike
writes



In years gone by - well until the early 80's in the UK on small
generators they used an incandescent lamp connected between the
voltage transformers situated either side of the circuit breaker and
tweaked the generator excitation to produce minimum brightness in the
lamp to ensure the generator was in phase with the grid system before
breaker closure.

Surely you tuned the generator for a steady MINIMUM (ideally zero)
brightness?

Somehow I wrote generator excitation instead of governor valve - I was
to bed late and up early!


They also, and more commonly, used a lamp as above and a synchroscope.

http://en.wikipedia.org/wiki/Synchroscope

Such sophistication! When I were I lad, we did it the 'ard way. The
university lecturers were 'ard - 'ard, but fair.

They've been around almost forever. Google images pictures some real
antiques.,


--

In article ,
Martin Brown writes:

You have to be kidding. You can have affordable or efficient thermopiles
but not both at the same time. It is very niche market.

I tried to put together a candle powered demo for an Xmas lecture using
them (fairly high grade units). I was intending to drive one puny LED
from the waste heat of a candle flame (about 100W).

I had a high temperature TEC module and a boring one stacked and even
operating it between 250C hot side to a large deep frozen heatsink -18C
on the cold side I could barely get enough juice out to do anything
useful. I decided that at these temperatures it was too hazardous for a
childrens' Xmas science lecture and scrapped the idea.

The same TEC units can move 50W or so from the hot plate to the cold
plate when suitably powered. But try to generate power with them with a
temperature difference applied and it is a lot less efficient. I would
be interested to know if anyone has found a setup that works - ideally
enough to power a 1W led (but I'd settle for 10mA and 4v).

I've used the 50W peltier devices. I found they generated power after
you've powered them off and there's still a temperature difference of
~40C across them - enough to continue self-powering their cooling fan
and a power-on LED for half a minute. I think these ones were rated
up to 250C, but I never ran them over 40-50C differential.

Even as heat pumps, they aren't efficient - it consumes 50W to pump
50W, but as a tiny heat pump, they can be very handy.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

js.b1 wrote:
On Dec 14, 11:02 am, harry wrote:
I often wonder if thermopiles might be a better alternative to PV
panels.

Geothermal all over wales, mendips etc, would be fine in the UK.

until that heat source was exhausted..

In article ,
Ian Jackson writes:
In message , Gary
writes
I was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

I have actually done this (at university, in 1963). It was a pretty
large three-phase generator (the size of a small car), and the object of
the exercise was to connect it to the three-phase mains. The generator
was driven by a DC motor.

Before connecting the generator to the mains, I had to adjust the speed
of the DC motor so that the generator was driven up to synchronous speed
and the correct phase angle (ie each phase of the generator was looking
at the correct phase of the mains). The generator DC field current was
then adjusted to that there was minimal voltage difference between the
generator and the mains.

When I was satisfied, and making sure that my fingers were well and
truly crossed, I then threw a big knife switch which connected the
generator to the mains.

I used to know one of the engineers who worked on Earley Power Station
(in Reading). They had a phase meter which showed how far out of phase
the generator was from the grid. When the needle was moving very slowly,
and coming up to zero, that was the point where it was connected in.
On the first runup of one of the generators, they were watcing a
duplicate phase meter, waiting for the control room to engage with the
grid. They watched it go slowly past zero without being switched in,
and relaxed as it would be another couple of minutes before it got
back into phase. Then there was an almighty bang or earthquake or
something, they didn't quite know for a moment. Anyway, turns out the
generator was put onto the grid completely out of phase. The control
room's phase meter was incorrectly connected up. His wife was shopping
in Heelas (now John Lewis) in the middle of Reading, and apparently
all the lights browned out. The generator had to be stripped down and
checked before it could be used again.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Martin Brown wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

I think you are failing to understand CHP. The point of CHP is to raise the
overall efficiency of the system by compromising on the efficiency of
components in the system. Slightly less efficient electricity generation
and comparatively inefficient heat great ion add to total thermal
efficiency higher than a good generator or a good boiler working alone.

For this sort of use a Stirling engine generator is good. There's (some)
mechanical output to generate electricity and a fair amount of waste heat
that can be used for space heating. It has the advantage that it provides
electricity when photovoltaic cannot - winter evenings. It's a great idea
for a sensibly managed energy economy.

On Dec 14, 12:07*pm, Martin Brown
wrote:
On 14/12/2011 11:02, harry wrote:





On Dec 14, 9:59 am, Martin
wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run *in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

As were PV panels at one time.
I often wonder if thermopiles might be a better alternative to PV
panels.

You have to be kidding. You can have affordable or efficient thermopiles
but not both at the same time. It is very niche market.

I tried to put together a candle powered demo for an Xmas lecture using
them (fairly high grade units). I was intending to drive one puny LED
from the waste heat of a candle flame (about 100W).

I had a high temperature TEC module and a boring one stacked and even
operating it between 250C hot side to a large deep frozen heatsink -18C
on the cold side I could barely get enough juice out to do anything
useful. I decided that at these temperatures it was too hazardous for a
childrens' Xmas science lecture and scrapped the idea.

The same TEC units can move 50W or so from the hot plate to the cold
plate when suitably powered. But try to generate power with them with a
temperature difference applied and it is a lot less efficient. I would
be interested to know if anyone has found a setup that works - ideally
enough to power a 1W led (but I'd settle for 10mA and 4v).

Previous toys have included candle powered nodding heat engine and a
heat engine that on a good day will run off a cup of fresh coffee.

Regards,
Martin Brown- Hide quoted text -

- Show quoted text -

In days of yore, every gas boiler was fitted with a thermocouple
safety device that held the gas valve open.
You should have nipped down to your local heating engineer/supplier.
For a few pounds you could have had one that worked.

On 14/12/2011 16:23, harry wrote:
On Dec 14, 12:07 pm, Martin
wrote:
On 14/12/2011 11:02, harry wrote:

On Dec 14, 9:59 am, Martin
wrote:
On 14/12/2011 09:48, harry wrote:

I had a high temperature TEC module and a boring one stacked and even
operating it between 250C hot side to a large deep frozen heatsink -18C
on the cold side I could barely get enough juice out to do anything
useful. I decided that at these temperatures it was too hazardous for a
childrens' Xmas science lecture and scrapped the idea.

In days of yore, every gas boiler was fitted with a thermocouple
safety device that held the gas valve open.
You should have nipped down to your local heating engineer/supplier.
For a few pounds you could have had one that worked.

Yes. They are good individually for 25mV open circuit or 10mV @ 0.2A.

But do you have any idea how many of them I would have needed to
generate 1W of electricity at 4v?

A back of the envelope calculation suggests about 400 or so thermocouple
junctions to provide the target 1W of output power at 4v and perhaps
half that number to get an LED glowing at low current.

The TEC modules at least have a decent number of junctions in series and
can source a voltage high enough to use semiconductors.

Regards,
Martin Brown

snip

*It might not be a mechanical rotating device, it could be, for
*example, a thermopile.

Thought that was somewhere in Greece?

--
No plan survives contact with the enemy.
[Not even bunny]

Helmuth von Moltke the Elder

(\__/)
(='.'=)
(")_(")

On Wed, 14 Dec 2011 14:18:08 +0000 (UTC),
(Andrew Gabriel) wrote:

I've used the 50W peltier devices. I found they generated power after
you've powered them off and there's still a temperature difference of
~40C across them - enough to continue self-powering their cooling fan
and a power-on LED for half a minute. I think these ones were rated
up to 250C, but I never ran them over 40-50C differential.

Even as heat pumps, they aren't efficient - it consumes 50W to pump
50W, but as a tiny heat pump, they can be very handy.

A friend had one of those in his narrowboat, powering a fan on the
stove top. In such a small space it was very effective.

On 14/12/2011 09:59, Martin Brown wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

Regards,
Martin Brown

Especially if you have a nice lump of fissionable material to keep it hot.

--

Graham.

%Profound_observation%

"Graham." wrote in message
...
On 14/12/2011 09:59, Martin Brown wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

Regards,
Martin Brown

Especially if you have a nice lump of fissionable material to keep it hot.

AFAIK there are no space craft (from Earth) that use fission (as in nuclear
reactors).
They just use the heat from decay.

On Dec 14, 10:51*pm, "dennis@home"
wrote:
"Graham." wrote in message

...





On 14/12/2011 09:59, Martin Brown wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

Regards,
Martin Brown

Especially if you have a nice lump of fissionable material to keep it hot.

AFAIK there are no space craft (from Earth) that use fission (as in nuclear
reactors).
They just use the heat from decay.- Hide quoted text -

- Show quoted text -


What was that Russian thing that came down in Australia years ago
that was radioactive?

On 14/12/2011 22:38, Graham. wrote:
On 14/12/2011 09:59, Martin Brown wrote:

Thermopiles are only really cost effective for space flight.

Especially if you have a nice lump of fissionable material to keep it hot.

It isn't fission powered. It is from short half life radioactive decay.

A concentrated solution of plutonium will boil under its own steam!
And they are running out of the favoured isotope PU238

http://www.space.com/5054-plutonium-...r-planets.html

Regards,
Martin Brown

Martin Brown wrote:

A concentrated solution of plutonium will boil under its own steam!
And they are running out of the favoured isotope PU238

And a chunk of plutonium oxide will glow cherry red

http://en.wikipedia.org/wiki/File:Radioisotope_thermoelectric_generator_plutoni um_pellet.jpg

"harry" wrote in message
...

What was that Russian thing that came down in Australia years ago
that was radioactive?

The Russians and the yanks have satellites powered by radioactive piles in
orbit.
They are spy stuff and they don't want to use solar panels as they would be
big, and make the satellite an easy target.
They are supposed to be boosted out of orbit at EOL but that one didn't go.

In article , Martin Brown wrote:
On 14/12/2011 11:02, harry wrote:
On Dec 14, 9:59 am, Martin
wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

https://en.wikipedia.org/wiki/Micro_...tec hnologies


Thermopiles are only really cost effective for space flight.

As were PV panels at one time.
I often wonder if thermopiles might be a better alternative to PV
panels.

You have to be kidding. You can have affordable or efficient thermopiles
but not both at the same time. It is very niche market.

There's research aimed at changing that:
http://www.newscientist.com/article/...-of-solar.html
But don't hold your breath.

(PV panels that are also solar thermal panels are another matter:
https://en.wikipedia.org/wiki/Photov...olar_collector
But no-one's suggesting they'll get hot enough to be worth using the heat
for additional electricity generation.)

dennis@home wrote:


"Graham." wrote in message
...
On 14/12/2011 09:59, Martin Brown wrote:
On 14/12/2011 09:48, harry wrote:

Insead of a boiler you would have a small electricity generator. The
heat from it would go to your house and it would be run in parallel
with the mains as with PV.
So there would be day time Summer electricity from PV and night time/
Winter electricity from co-generation, possibly DC via the same
inverter to get over synchronisation problems.

It might not be a mechanical rotating device, it could be, for
example, a thermopile.

ITYM a fuel cell using the waste heat to warm water.
The Japanese Prime Ministers residence has one such installation -
although they have gone very quiet about how well it is working.

Thermopiles are only really cost effective for space flight.

Regards,
Martin Brown

Especially if you have a nice lump of fissionable material to keep it
hot.

AFAIK there are no space craft (from Earth) that use fission (as in
nuclear reactors).
They just use the heat from decay.

decay comes from fission

On Wed, 14 Dec 2011 14:27:08 +0000, The Natural Philosopher wrote:

js.b1 wrote:
On Dec 14, 11:02 am, harry wrote:
I often wonder if thermopiles might be a better alternative to PV
panels.

Geothermal all over wales, mendips etc, would be fine in the UK.

until that heat source was exhausted..

But doesn't some geothermal energy come from the expansion/compression of
the earth due to solar gravity ?

I was amazed, watching Prof. Cox "Wonders of the Solar System" to learn
that one of the moons of Saturn has a molten core due to this effect.

Jethro wrote:

On Wed, 14 Dec 2011 14:27:08 +0000, The Natural Philosopher wrote:

js.b1 wrote:
On Dec 14, 11:02 am, harry wrote:
I often wonder if thermopiles might be a better alternative to PV
panels.

Geothermal all over wales, mendips etc, would be fine in the UK.

until that heat source was exhausted..

But doesn't some geothermal energy come from the expansion/compression of
the earth due to solar gravity ?

I was amazed, watching Prof. Cox "Wonders of the Solar System" to learn
that one of the moons of Saturn has a molten core due to this effect.

Isn't there some idea that nuclear reactions are also happening in the
earth's core?



--
Tim Watts

On Dec 14, 11:25*am, Ian Jackson
wrote:
In message , Gary
writesI was wondering what would happen if you connected a working generator
to the mains whilst power was on.

I am asuming it would not be a good thing?? anybody actually know what
happens?

I have actually done this (at university, in 1963). It was a pretty
large three-phase generator (the size of a small car), and the object of
the exercise was to connect it to the three-phase mains. The generator
was driven by a DC motor.

Before connecting the generator to the mains, I had to adjust the speed
of the DC motor so that the generator was driven up to synchronous speed
and the correct phase angle (ie each phase of the generator was looking
at the correct phase of the mains). The generator DC field current was
then adjusted to that there was minimal voltage difference between the
generator and the mains.

When I was satisfied, and making sure that my fingers were well and
truly crossed, I then threw a big knife switch which connected the
generator to the mains.

I then increased the field current so that the generator started
generating (ie current started to flow into the mains). At the same
time, I had to adjust the field current of the DC motor so that its
power output to the drive shaft of the generator also increased
(otherwise the generator would have started to lack power, and become a
motor).

The experiment then continued with me monitoring and plotting on graphs
all the relevant currents and voltages while the generator was behaving
as both a generator and a synchronous motor. I recall that, in one
condition, the generator can be made to behave as a capacitor to the
mains feed, and this used to be one method of providing variable amounts
power factor correction.

BTW, don't try this at home! ;o))
--
Ian
I remember doing this experiment about ten years later - if you
included the time to write it up it made the best part of half a day's
work.
I remember the lab also had a kit for doing measurments on a DC motor
using another DC motor, used as a generator, to provide the load to be
driven. Once it was up and running the external DC supply would only
be supplying power to make up for the losses in the system; the
generator would be supplying most of the current to drive the motor.
Sadly I never saw it run up - it must have been pretty impressive;
they were motors out of a German WW1 submarine, as I recall, and
something over a metre diameter and a metre long.
Mike