Replacement transformer
 

Phil Allison wrote:

"David Looser"

Snubbers are not necessarily "two components in one box". In many cases
*one* component supplied both the resistance and capacitance.

** Post a link that proves that.

I'd be interested to see that too.

Actually I have a feeling it would, in fact MUST, contravene IEC60065. The
capacitor would have to be X Class at least

Graham

Replacement transformer
 

"Dave Plowman (News)" wrote:

Phil Allison wrote:

I do wish you'd give up talking about your country like it is the world -
thought only the septics did that.

Australia uses essentially the same IEC standards as we do but by another
name.

Graham

Replacement transformer
 

David Looser wrote:

"Phil Allison" wrote
"David Looser"

Snubbers are not necessarily "two components in one box". In many cases
*one* component supplied both the resistance and capacitance.

** Post a link that proves that.

Start behaving like a human being, and I might.

By Phil's former standards, he's been very moderate so far.

Graham

Replacement transformer
 

"Eeyore" wrote in message
...


Phil Allison wrote:

"David Looser"

Snubbers are not necessarily "two components in one box". In many cases
*one* component supplied both the resistance and capacitance.

** Post a link that proves that.

I'd be interested to see that too.

Actually I have a feeling it would, in fact MUST, contravene IEC60065. The
capacitor would have to be X Class at least

That's as maybe. Snubbers pre-date IEC60065 by more than a century.

David.

Replacement transformer
 

David Looser wrote:

"Eeyore" wrote
Phil Allison wrote:
"David Looser"

Snubbers are not necessarily "two components in one box". In many cases
*one* component supplied both the resistance and capacitance.

** Post a link that proves that.

I'd be interested to see that too.

Actually I have a feeling it would, in fact MUST, contravene IEC60065. The
capacitor would have to be X Class at least

That's as maybe. Snubbers pre-date IEC60065 by more than a century.

IEC65 as it was then has been around for over 30 years.

Graham

Replacement transformer
 

"Dave Plowman (News)" wrote in message
...

The HMV had a mains energised speaker - the coil acting as a smoothing
choke,

Common practice in those days, power the speaker field coil *and* save on a
smoothing choke.

and yes there was audible hum. There was an extension speaker in
another room with a permanent magnet which was slightly cleaner.

Some time ago I adapted an HMV radiogram from that period to be a prop in an
amateur production of "Blithe Spirit" by Noel Coward. In that play the
"ghost", Elvira, plays a record of the song "Always" several times on an
on-set radiogram. In our production the recording was played in from a
back-stage tape machine (I said it was some time ago!, these days I'd use a
PC) but I wanted the sound to come from the radiogram. So I connected the
radiogram's own speaker to the output of the modern back-stage amplifier.
However as this was an enegised speaker I needed to power the field coil.
The radiogram's service sheet told me what voltage and current it required,
70V 35mA IIRC (2Kohm coil). So I made up a power supply using a 783
high-voltage regulator chip. It worked a treat, with no hum. Though I
suppose to be strictly authentic I should have provided some :-).

BTW the transformer I used was one of those encapsulated PCB mounting types.
I think it was class 2 though I can't be sure. In any case since this PSU
was housed inside the radiogram cabinet and was connected only to the
speaker field coil it didn't actually matter a ****.


David.

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In message , Eeyore
writes


Ian Jackson wrote:

So 240V is 'normal'.

Try telling Chinese manufacturers of cheap wall warts that ! I had one
that would
audibly buzz around 250V.

Graham

Oh yes! At work, I got involved in investigating why one simple type of
Far Eastern wall wart was failing with an O/C primary (thermal fuse
problem). It was because there was simply nowhere near enough iron in
the transformer. Even with no load, a plot of I/P current vs I/P volts
rapidly shot off into outer space at 230V. We concluded that it was
either really designed for 220V or for 60Hz.
--
Ian

Replacement transformer
 

"Don Pearce" wrote in message
et

Arny Krueger wrote:


Please refresh my memory Graham, but was there, or was
their not one or more world-class air forces that
operated bomber groups out of the UK during WW2? OK, so
we (the gold ole USA) came in at your request and helped
you. ;-)

Anyone who thinks the USA joined WWII to help us out is
seriously misreading history (and a well-developed sense
of USA self-interest).

Well, we did think of the UK as "The world's largest aircraft carrier", and
said so in those words.

However, if you backspace a few years, we've got the judgment of history
that says that after WW1 the allies set Germany up for bad times by
demanding and collecting ruinous reparation payments. History is often like
"Murder On The Orient Express": Everybody did it.

And of course you do get a rather
lop-sided view of warfare when you only ever experience
war in foreign countries.

That long, bloody period of aversion therapy we had in the 1860s seems to
have stuck with us, pretty well.

Replacement transformer
 

"Ian Jackson"

Oh yes! At work, I got involved in investigating why one simple type of
Far Eastern wall wart was failing with an O/C primary (thermal fuse
problem). It was because there was simply nowhere near enough iron in the
transformer. Even with no load, a plot of I/P current vs I/P volts rapidly
shot off into outer space at 230V.


** Nearly all compact transformer type AC adaptors operate the iron core
well into magnetic saturation making for a rather high Imag value at rated
AC voltage.

Often the off load VA consumption figure is the same as the on load one.

Nothing is wrong - by this simple means, the bests voltage regulation is
obtained with the least amount of iron and copper.


We concluded that it was either really designed for 220V or for 60Hz.


** One off freaks exist.

Many of them post here as wannabe experts.



......... Phil

Replacement transformer
 

"Eeyore" wrote in
message

American industry did wonderfully out of it, esp not
having to worry about air raids.

We did have problems with German submarines off the east coast and in the
Gulf of Mexico.

Despite all of which the
RAF dropped a far greater percentage of tonnage of bombs
in Europe than the USAAC/USAAF.

Yes, but we were basically fighting two wars against two different world
powers, in two different major oceans and on two different major continents,
all at the same time.