Bought a 1.6VA 22v toroidal transformer from Digikey some time back. Part
of an order where I made it up to free postage.

It's labelled Talema - but unlike UK ones has no diagram or other
information like spec etc printed on it. So downloaded the PDF from the
Digikey site - but was in a bit of a rush when looking at it. And the
diagram I saw suggested the primary would be the usual - blue and brown
for 230 volt with the other ends of the 115v windings just linked. But I
looked at the wrong diagram. Blue and brown was actually one of the
secondary windings...

--
*Drugs may lead to nowhere, but at least it's the scenic route *

Dave Plowman London SW
To e-mail, change noise into sound.

On Friday, November 29, 2013 6:14:47 PM UTC, Dave Plowman (News) wrote:
Blue and brown was actually one of the
secondary windings...

That would have been a bit tingly on the output!

Owain

BigBang then?

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Dave Plowman (News)" wrote in message
...
Bought a 1.6VA 22v toroidal transformer from Digikey some time back. Part
of an order where I made it up to free postage.

It's labelled Talema - but unlike UK ones has no diagram or other
information like spec etc printed on it. So downloaded the PDF from the
Digikey site - but was in a bit of a rush when looking at it. And the
diagram I saw suggested the primary would be the usual - blue and brown
for 230 volt with the other ends of the 115v windings just linked. But I
looked at the wrong diagram. Blue and brown was actually one of the
secondary windings...

--
*Drugs may lead to nowhere, but at least it's the scenic route *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
"Dave Plowman (News)" writes:
Bought a 1.6VA 22v toroidal transformer from Digikey some time back. Part
of an order where I made it up to free postage.

It's labelled Talema - but unlike UK ones has no diagram or other
information like spec etc printed on it. So downloaded the PDF from the
Digikey site - but was in a bit of a rush when looking at it. And the
diagram I saw suggested the primary would be the usual - blue and brown
for 230 volt with the other ends of the 115v windings just linked. But I
looked at the wrong diagram. Blue and brown was actually one of the
secondary windings...

You get quite an impressive bang when you connect a switched
mode PSU to the mains, which turns out to be 120V-only input...

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

On Tuesday, December 3, 2013 8:15:54 AM UTC+13, Andrew Gabriel wrote:

You get quite an impressive bang when you connect a switched
mode PSU to the mains, which turns out to be 120V-only input...

I'm told that you get an impressive bang if you leave the secondary open-circuit on a 5000 to 1 toroidal current transformer. I never dared try it.

In article ,
Matty F writes:
On Tuesday, December 3, 2013 8:15:54 AM UTC+13, Andrew Gabriel wrote:

You get quite an impressive bang when you connect a switched
mode PSU to the mains, which turns out to be 120V-only input...

I'm told that you get an impressive bang if you leave the secondary open-circuit on a 5000 to 1 toroidal current transformer. I never dared try it.

It generates a high voltage on the secondary, which comes as a
big surprise to people who handle them but don't understand the
principles, as the secondary voltage in proper use is extremely
low, and safe to touch. I imagine the secondary winding insulation
would break down eventually, and then it would get very hot if a
single turn shorted out. If it melted through the insulation of
the main pass-through conductor, you could get a big bang.

If there's no load for a current transformer (such as a moving
iron ammeter), then the secondary output should be shorted out
to prevent damage to the transformer and avoid the unexpected
high voltage on the terminals.

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

Andrew Gabriel wrote:

In article ,
Matty F writes:

I'm told that you get an impressive bang if you leave the secondary open-circuit on a 5000 to 1 toroidal current transformer. I never dared try it.

It generates a high voltage on the secondary, which comes as a
big surprise to people who handle them but don't understand the
principles, as the secondary voltage in proper use is extremely
low, and safe to touch. I imagine the secondary winding insulation
would break down eventually, and then it would get very hot if a
single turn shorted out. If it melted through the insulation of
the main pass-through conductor, you could get a big bang.

Somewhat different, I was once working on a prototype ac voltage
detection relay, with a laminated core. It buzzed unacceptably,
so someone suggested a shaded pole. I didn't have a suitable
piece of copper to hand, so brazed a short length into a loop,
and inserted it into a slot cut into the laminations. I have to
admit to being a little skeptical about the change of success.

Confounding my doubts, it worked a treat, but after a very short
time, the current flowing in the copper melted the brazing
material.

The production version had a section cut off a suitable copper
tube, and is still running round the railways.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.