In article ,
Tim Streater wrote:
In article , Roger Hayter
wrote:

Tim Streater wrote:

In article , Roger Hayter
wrote:

it's ferrite rod

its

(Before the evil EU made us change to 198kHz.)

Nothing to do with the EU, of course, else the Yanks would still be
using c/s.

It has that in common with 95% of what the EU is blamed for in the
popular imagination, and much of the remaining 5% was a British
initiative anyway. And the channelisation of LW must have been
someone's fault, I liked the nice round number.

You mean we were running the EU? Gosh - who knew? They certainly kept
*that* quiet.

The frequency changes were under the auspices of a UN agency - not an EU
one.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 04/12/2018 16:23, Roger Hayter wrote:
And second because
of increasing capacitative losses.
But capacitors dont have losses.


--
Climate Change: Socialism wearing a lab coat.

On 04/12/2018 16:23, Roger Hayter wrote:
It has that in common with 95% of what the EU is blamed for in the
popular imagination, and much of the remaining 5% was a British
initiative anyway.

The renewable obligation which costs this country far more than its net
payments to the EU, is entirely an EU initiative.

We could not scrap it if we wanted to.


--
Climate Change: Socialism wearing a lab coat.

On 04/12/2018 16:52, charles wrote:
In article ,
Tim Streater wrote:
In article , Roger Hayter
wrote:

Tim Streater wrote:

In article , Roger Hayter
wrote:

it's ferrite rod

its

(Before the evil EU made us change to 198kHz.)

Nothing to do with the EU, of course, else the Yanks would still be
using c/s.

It has that in common with 95% of what the EU is blamed for in the
popular imagination, and much of the remaining 5% was a British
initiative anyway. And the channelisation of LW must have been
someone's fault, I liked the nice round number.

You mean we were running the EU? Gosh - who knew? They certainly kept
*that* quiet.

The frequency changes were under the auspices of a UN agency - not an EU
one.

sssh. don't confuse with facts



--
Climate Change: Socialism wearing a lab coat.

In article ,
says...

Thicker wire has more surface area, ****, do you need everything spelled
out?

And the wire may be thick, but is has way more self-awareness than you.

Interesting because, although the skin effect increases with
frequency, much thinner solid wire was used in all the Band
I/III VHF tuners covering up to 220MHz (260MHz for the
oscillator coil).

The lengths, of course, were much shorter.
--

Terry

---
This email has been checked for viruses by AVG.
https://www.avg.com

On Tuesday, 4 December 2018 10:50:35 UTC, The Natural Philosopher wrote:


And 'elecronic transformers' are in any case rectified and smoothed..
...the interference of 50watts of 50KHz RF would be massive.

Some may be, but not the ones I bought from TLC around 7 years ago. The
output was a bipolar square wave at around 25kHz 100% modulated by 50 Hz.

John

In article ,
says...


Every transistor radio had a long wave coil on
it's ferrite rod wound in Litz wire to mitigate skin effect at 200kc/s.
(Before the evil EU made us change to 198kHz.)

We changed frpm c/s tp Hz years before we joined what was then
the EEC.

--

Terry

---
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https://www.avg.com

"Harry Bloomfield" wrote in message
news
FMurtz was thinking very hard :
This was not said by F Murtz (me ) it was Paul Saccani

There was no post I was able to find, from a Paul Saccani and you didn't
directly quote one.

He quoted it in his original post.

The Natural Philosopher wrote:

On 04/12/2018 16:23, Roger Hayter wrote:
And second because
of increasing capacitative losses.
But capacitors dont have losses.

Parasitic ones with random stuff as dielectric certainly do. In any
case, the problem with parasitic capacitance is having to have more wire
to achieve the same L:C ratio which is needed for other reasons. This
is a bit off-topic, but excessive parasitic capacitance is definitely a
bad thing.


--

Roger Hayter

The Natural Philosopher wrote:

On 04/12/2018 16:23, Roger Hayter wrote:
It has that in common with 95% of what the EU is blamed for in the
popular imagination, and much of the remaining 5% was a British
initiative anyway.

The renewable obligation which costs this country far more than its net
payments to the EU, is entirely an EU initiative.

And the UK government was one of the prime movers in it becoming EU
policy. Not the only one, obviously.


We could not scrap it if we wanted to.


--

Roger Hayter

Roger Hayter a écrit :

That's simply not true. Every transistor radio had a long wave coil on
it's ferrite rod wound in Litz wire to mitigate skin effect at 200kc/s.
(Before the evil EU made us change to 198kHz.)

+1
Many coils on toroid cores use parallel wires.
Also horizontal deflecting coils for CRT.

On Tuesday, 4 December 2018 20:09:05 UTC, Roger Hayter wrote:
The Natural Philosopher wrote:
On 04/12/2018 16:23, Roger Hayter wrote:

And second because
of increasing capacitative losses.
But capacitors dont have losses.

Parasitic ones with random stuff as dielectric certainly do. In any
case, the problem with parasitic capacitance is having to have more wire
to achieve the same L:C ratio which is needed for other reasons. This
is a bit off-topic, but excessive parasitic capacitance is definitely a
bad thing.

FR4 capacitance tempco is about 800ppm/C.


NT

On 04/12/2018 10:27, Andy Burns wrote:
FMurtz wrote:

This was not said by F Murtz (me ) it was Paul Saccani

IME you didn't make it very clear you were quoting someone else

http://al.howardknight.net/msgid.cgi?ID=154391911200

Life's too short guys

Bill

Bill Wright wrote:
On 04/12/2018 10:27, Andy Burns wrote:
FMurtz wrote:

This was not said by F Murtz (me ) it was Paul Saccani

IME you didn't make it very clear you were quoting someone else

http://al.howardknight.net/msgid.cgi?ID=154391911200

Life's too short guys

Bill
It started out in aus.cars and this Paul Saccani often chimes in with
highly technical and sometimes wrong but often right stuff that is not
always needed in simple conversations.

FMurtz wrote:
Bill Wright wrote:
On 04/12/2018 10:27, Andy Burns wrote:
FMurtz wrote:

This was not said by F Murtz (me ) it was Paul Saccani

IME you didn't make it very clear you were quoting someone else

http://al.howardknight.net/msgid.cgi?ID=154391911200

Life's too short guys

Bill
It started out in aus.cars and this Paul Saccani often chimes in with
highly technical and sometimes wrong but often right stuff that is not
always needed in simple conversations.

This is paul's latest contribution which started out as a simple question,
The question,
I want to run a 12v 20 watt LED light. For arguments sake, it's approx a
20 metres away from a 12v battery bank that consists of 4 x 12v truck
batteries, which are fed by a 200w solar panel.

I was going to buy a roll of this: 4mm
https://www.ebay.com.au/itm/Twin-Cor...U Q:rk:7:pf:0

Says it's SAA approved, good for 22 amps, but unable to be delivered
until perhaps 24th december, but maybe earlier...!!

Or should I go for 6mm
https://www.ebay.com.au/itm/Twin-Cor...U!-1:rk:8:pf:0

Paul's latest,

What it doesn't say is 4mm^2, but if that is what it is, then it
should *not* be used to deliver 22 amps over 20m at 12V. The voltage
drop is 3.74V, a whopping 31% loss used to heat the wire, 82 W worth
of wasted power.

Believe it or not, what you would want for 22 A, 12V over 20m is a
65mm^2 cable. Distance matters. You get the same voltage drop if you
use 24V, but you have much less waste heat.

That same cable could transmit 60A over 200 km with less than 3%
losses, at 220 kV.....


Usually the first question is, is it an aerial, is it in conduit, is
it on a surface with clips, is it under insulation? But this load is
so trivial. Forget about setting things on fire with anything over
1mm^2.

If you go with 1mm^2, voltage drop is 1.16V, therefore the wire
generates less than 2 W of heat. Sure, you've wasted about 10% of
your power, but it isn't catching fire any time soon.

Normal practice is to limit voltage drop to 3%, so a maximum of 0.36 V
is acceptable at 12V. Therefore, by calculation you want a conductor
of 3.2mm^2 or more, which if your first option is 4mm^2 and not "4mm
Industry", is ample for.

Having said that, I don't think 2.5 mm^2 TPS 2C&E is out of the
question if you have it lying around, but you'll be wasting 3.8% of
the power you deliver.

However, there is an issue as to the nature of the LED. Good ones
have a current limiting circuit and tolerate a wide range of voltages,
typically 10-30 V AC/DC. Many cheap ones just have a volt drop
resistor, designed to prevent excess current at 14.5-15 VDC -
sometimes these will stop working at 11.5 V or thereabouts. So
dependant on what kind of LED you are using, the voltage drop could be
quite critical as to whether or not and for how long (battery state of
charge) the light would work.

You could use diodes to provide a modest supply at 24V from the
existing battery configuration and use easily available (or
convertible) 24 V LED fittings.

For under $10, you could get a buck converter with a 250W rating to
take the "12V" up to 28V (nominal 24V) with a current limiting
fitting. This will also make sure your lighting works the same over a
much wider state of charge of the batteries. You save on copper and
get a better end result. You could also use a buck converter to 60V
and another at the other end to take it down to 12V. Whether this is
worthwhile depends on the cost of the wire.

With 1mm^2 at 28V, you then get a voltage drop of 0.49V, 1.75% for a
20W light. 0.35W wasted instead of 2W.

Personally, I use 48V lighting to make life easy on the lighting
front, but 28V (nominally 24V) makes a huge difference and is much
easier to source lighting for..

I can't remember if I stressed this before, but with regard to your
inverter, it is unlikely to be an isolated type. If you allow
"neutral" to be earthed, the case become live at 110-120 V WRT earth.
Also be aware that conventional switching is only on the active, so if
you poke around in equipment connected to such an inverter, it is
still might be live if the equipment switch is off. It is OK to earth
the case.

As the output is not referenced to earth, this is safer in some ways
compared with normal domestic power.

6 mm is good for about 63 A, too generous for sure.
--
Cheers,
Paul Saccani
Perth, Western Australia.

On 06/12/2018 09:12, FMurtz wrote:
FMurtz wrote:
Bill Wright wrote:
On 04/12/2018 10:27, Andy Burns wrote:
FMurtz wrote:

This was not said by F Murtz (me ) it was Paul Saccani

IME you didn't make it very clear you were quoting someone else

http://al.howardknight.net/msgid.cgi?ID=154391911200

Life's too short guys

Bill
It started out in aus.cars and this Paul Saccani often chimes in with
highly technical and sometimes wrong but often right stuff that is not
always needed in simple conversations.

This is paul's latest contribution which started out as a simple question,
The question,
I want to run a 12v 20 watt LED light. For arguments sake, it's approx a
20 metres away from a 12v battery bank that consists of 4 x 12v truck
batteries, which are fed by a 200w solar panel.

I was going to buy a roll of this: 4mm
https://www.ebay.com.au/itm/Twin-Cor...U Q:rk:7:pf:0


Says it's SAA approved, good for 22 amps, but unable to be delivered
until perhaps 24th december, but maybe earlier...!!

Or should I go for 6mm
https://www.ebay.com.au/itm/Twin-Cor...U!-1:rk:8:pf:0


Paul's latest,

What it doesn't say is 4mm^2, but if that is what it is, then it
should *not* be used to deliver 22 amps over 20m at 12V.* The voltage

Perhaps you should school him in power = voltage x current, and
therefore 20 / 12 22


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thursday, 6 December 2018 09:12:46 UTC, FMurtz wrote:

I want to run a 12v 20 watt LED light. For arguments sake, it's approx a
20 metres away from a 12v battery bank that consists of 4 x 12v truck
batteries, which are fed by a 200w solar panel.

big snip

2x12v leds in series on 24v certainly makes life easier, if the batteries aren't already set up as 12v for some other purpose.

And don't forget T&E has 3 conductors, 2 of which can be parallelled to reduce V drop a little. Or if you have 1mm^2 lying around you could use 2 lengths of that, all 3 conductors parallelled. Etc.


NT

In article ,
writes:
On Tuesday, 4 December 2018 10:50:35 UTC, The Natural Philosopher wrote:


And 'elecronic transformers' are in any case rectified and smoothed..
...the interference of 50watts of 50KHz RF would be massive.

Some may be, but not the ones I bought from TLC around 7 years ago. The
output was a bipolar square wave at around 25kHz 100% modulated by 50 Hz.

None are rectified - the loss in a rectifier at 50kHz would just be a
pointless waste and well exceed all the existing losses in an electronic
transformer. The transformer secondary is connected directly to the
output terminals with no other circuitry on the secondary side.

It's modulated at 100Hz (not 50Hz) because there's no mains input
smoothing capacitor, so it works on a mains phase angle dimmer.

(LED transformers are rectified.)

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