Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?

micky forklarede den 16-12-2013:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?

In civilized countries with a modern electric system, we have 230v,
allowing for using less copper/alu in the cables.

When we get equipment from backward countries with only 110v, we use an
autotransformer to step down the voltage.

An autotransformer use less wire than a "normal" transformer, but does
not give isolation between primary and secondary.

Leif

.... with 230 and 400v in the house.


--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

On 12/16/2013 07:01 AM, Leif Neland wrote:
micky forklarede den 16-12-2013:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)
What are they used for?

In civilized countries with a modern electric system, we have 230v,
allowing for using less copper/alu in the cables.

When we get equipment from backward countries with only 110v, we use an
autotransformer to step down the voltage.

An autotransformer use less wire than a "normal" transformer, but does
not give isolation between primary and secondary.

Leif

... with 230 and 400v in the house.



Pretty useless in the shop here. Trade it for a dim bulb tester.

On 12/16/2013 06:15 AM, micky wrote:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?




I think the description is faulty an autoformer with 240Vac winding and
120Vac winding doesn't make any sense. It would go from zero to 250 or
so or zero to 140 or so. are you sure it only has one winding?

On Mon, 16 Dec 2013 08:01:01 -0700, Leif Neland wrote:

...snip....
In civilized countries with a modern electric system, we have 230v,
allowing for using less copper/alu in the cables.

When we get equipment from backward countries with only 110v, we use an
autotransformer to step down the voltage.

An autotransformer use less wire than a "normal" transformer, but does
not give isolation between primary and secondary.

Leif

... with 230 and 400v in the house.



LOL! Thanks, I needed that today.

Of course, here in the US we should be happy that Edison LOST out
regarding his DC distribution system. Wasn't Edison the one who invented
the Electric Chair just to discredit his competitor [Tesla, Westinghouse]?
He wanted to show how lethal these high voltages were, but alas, his first
three testers died rather badly, inhumanely.

On 12/16/2013 07:18 AM, dave wrote:
On 12/16/2013 06:15 AM, micky wrote:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?




I think the description is faulty an autoformer with 240Vac winding and
120Vac winding doesn't make any sense. It would go from zero to 250 or
so or zero to 140 or so. are you sure it only has one winding?

If it's an isolation transformer the numbers make more sense and it is
very valuable on a bench.

On 12/16/2013 07:32 AM, RobertMacy wrote:
On Mon, 16 Dec 2013 08:01:01 -0700, Leif Neland wrote:

...snip....
In civilized countries with a modern electric system, we have 230v,
allowing for using less copper/alu in the cables.

When we get equipment from backward countries with only 110v, we use
an autotransformer to step down the voltage.

An autotransformer use less wire than a "normal" transformer, but does
not give isolation between primary and secondary.

Leif

... with 230 and 400v in the house.



LOL! Thanks, I needed that today.

Of course, here in the US we should be happy that Edison LOST out
regarding his DC distribution system. Wasn't Edison the one who invented
the Electric Chair just to discredit his competitor [Tesla,
Westinghouse]? He wanted to show how lethal these high voltages were,
but alas, his first three testers died rather badly, inhumanely.

We may end up with DC wiring after all. It is much easier to implement
PV in a pure DC environment. Maybe 240Vac from the grid for the major
appliances and locally generated 14/24VDC for lights and doodads.

On Mon, 16 Dec 2013, micky wrote:

Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?

Check whatever else is being offered by the guy.

I found a nice 120 to 220 transformer in a pile of garbage earlier this
year, thought about, and couldn't think of a reason to bring it home,
especially with that weight.

I dig a bit more in the pile, and find a sander, one of those ones with a
sort of shovel part at the front for the sandpaper. So i bring that home,
not really paying attention to it.

I get home, and I then notice the plug is wrong, and the label says it's
for 220v.

There was a reason that transformer was there, it was for the sander.

Michael

dave submitted this idea :
On 12/16/2013 06:15 AM, micky wrote:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?




I think the description is faulty an autoformer with 240Vac winding and
120Vac winding doesn't make any sense. It would go from zero to 250 or so or
zero to 140 or so. are you sure it only has one winding?

A 240/120 Auto transformer is just a 240 volt winding with a tap
halfway up. Very dangerous if you take your 120 off the top half
instead of 5the bottom.

--
John G

John G sendte dette med sin computer:


A 240/120 Auto transformer is just a 240 volt winding with a tap halfway up.
Very dangerous if you take your 120 off the top half instead of 5the bottom.

Why should that be dangerous?

Surely you do not rely on the which wire is live and which is neutral,
and have the neutral connected to the cabinet or something?

Or are your insulation so bad it cannot withstand 240 volt to ground?

Leif

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

Leif Neland wrote :
John G sendte dette med sin computer:


A 240/120 Auto transformer is just a 240 volt winding with a tap halfway
up. Very dangerous if you take your 120 off the top half instead of 5the
bottom.

Why should that be dangerous?

Surely you do not rely on the which wire is live and which is neutral, and
have the neutral connected to the cabinet or something?

Or are your insulation so bad it cannot withstand 240 volt to ground?

Leif

All you say is correct BUT
If you assume the 120 volts is just like the normalUS supply rhen you
could get into trouble because connected to the top you now have 240
volts on one line and 120 on the other instead of Ground or near enough
on one and 120 on the other.

--
John G

"Leif Neland"


A 240/120 Auto transformer is just a 240 volt winding with a tap halfway
up. Very dangerous if you take your 120 off the top half instead of 5the
bottom.

Why should that be dangerous?

Surely you do not rely on the which wire is live and which is neutral, and
have the neutral connected to the cabinet or something?

Or are your insulation so bad it cannot withstand 240 volt to ground?


** Old US made items ( audio, radio TV etc ) have no connection to ground so
the chassis floats at some mid voltage OR is linked to one side of the
incoming AC line with a capacitor. The cap is usually either 0.1uF or 0.05
uF @ 400V DC.

The plug can be reversed so the user is supposed to find the way that links
that cap to neutral and so brings the chassis down to a low voltage. This
will result is less hum and noise in the sound.

If used with a auto tranny from a 240V supply, the cap ( aka " death cap" )
can bring the chassis to 240V or itself experience 240 VAC if the chassis is
grounded by another item. 240VAC is more than such caps can stand and they
often fail short.

With guitar amps, this situation is particularly lethal - hence the title
"death cap"'.

FYI:

An auto tranny will deliver full AC line voltage on BOTH output wires
simply if the neutral is not connected at the supply end.



.... Phil

John G har bragt dette til verden:
Leif Neland wrote :
John G sendte dette med sin computer:


A 240/120 Auto transformer is just a 240 volt winding with a tap halfway
up. Very dangerous if you take your 120 off the top half instead of 5the
bottom.

Why should that be dangerous?

Surely you do not rely on the which wire is live and which is neutral, and
have the neutral connected to the cabinet or something?

Or are your insulation so bad it cannot withstand 240 volt to ground?

Leif

All you say is correct BUT
If you assume the 120 volts is just like the normalUS supply rhen you could
get into trouble because connected to the top you now have 240 volts on one
line and 120 on the other instead of Ground or near enough on one and 120 on
the other.

Yeah, but do you say "This is the neutral connection, I can touch this
safely"?

Assume everything is "hot". Just like my father taught me: Check it is
unloaded, and then treat it as if it was loaded.

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

Leif Neland laid this down on his screen :
John G har bragt dette til verden:
Leif Neland wrote :
John G sendte dette med sin computer:


A 240/120 Auto transformer is just a 240 volt winding with a tap halfway
up. Very dangerous if you take your 120 off the top half instead of 5the
bottom.

Why should that be dangerous?

Surely you do not rely on the which wire is live and which is neutral, and
have the neutral connected to the cabinet or something?

Or are your insulation so bad it cannot withstand 240 volt to ground?

Leif

All you say is correct BUT
If you assume the 120 volts is just like the normalUS supply rhen you could
get into trouble because connected to the top you now have 240 volts on one
line and 120 on the other instead of Ground or near enough on one and 120
on the other.

Yeah, but do you say "This is the neutral connection, I can touch this
safely"?

Assume everything is "hot". Just like my father taught me: Check it is
unloaded, and then treat it as if it was loaded.

Yeah! But stop arguing. the facts are there.
Some people don't know as much as you, you smart a..

There is too much "I did it it must be right" in this forum

When you are only guessing about the whole picture

--
John G

Phil Allison formulerede spørgsmålet:

FYI:

An auto tranny will deliver full AC line voltage on BOTH output wires simply
if the neutral is not connected at the supply end.

So no voltage across the device connected.

Just as any device will have full AC line voltage on both inputs if the
neutral is not connected in the wall socket. But no power.

Heck, if you have two/three-phase supply, and the ground is
disconnected, you can get double or 1.7*line voltage. WITH power.



--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

Leif Neland wrote:
micky forklarede den 16-12-2013:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?

In civilized countries with a modern electric system, we have 230v,
allowing for using less copper/alu in the cables.

don't forget you waste more iron in magnetics with that 50Hz stuff.

On Mon, 16 Dec 2013 07:35:44 -0800, dave
wrote:

On 12/16/2013 07:18 AM, dave wrote:
On 12/16/2013 06:15 AM, micky wrote:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?




I think the description is faulty an autoformer with 240Vac winding and
120Vac winding doesn't make any sense. It would go from zero to 250 or
so or zero to 140 or so. are you sure it only has one winding?

There was a picture and it clearly said autotransformer, no capital a,
in big letters.

I'm in the US btw, if anyone thought otherwise.

If it's an isolation transformer the numbers make more sense and it is
very valuable on a bench.

Yeah, I've wanted one of those for a long time. I'm still alive so
no harm done. ;-)

dave skrev den 16-12-2013:
On 12/16/2013 06:15 AM, micky wrote:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?




I think the description is faulty an autoformer with 240Vac winding and
120Vac winding doesn't make any sense. It would go from zero to 250 or so or
zero to 140 or so. are you sure it only has one winding?

You are confusing autotransformers with variotransformers.

Actually, most variotransformers are also autotransformers, a subset
with a movable tap.

Some variotransformers come with an isolation transformer, so you are
relative safe as long as you only touch the hot circuit with one hand.

Leif

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

dave wrote:

On 12/16/2013 06:15 AM, micky wrote:
Someone on Freecycle is giving away an autotransformer. with
220/240-volt input and single 110-120-volt output. 1-Amp fuse. Made in
England.

Do I have any use for that for repair work or anything? Since there
is already 120 in the house, I don't think so, but in the picture it
looks like new. ;-)

What are they used for?




I think the description is faulty an autoformer with 240Vac winding and
120Vac winding doesn't make any sense. It would go from zero to 250 or
so or zero to 140 or so. are you sure it only has one winding?


It is a 240 volt transformer with a center tap. An autotransformer
provides no isolation.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.