Latest horror...

[echoes]

850 VA auto transformer - nice; Unless it was massively oversized, that would have lit something up well. Get it on eBay - might be worth a few quid to someone!

 

[Roger465]

850 VA auto transformer - nice; Unless it was massively oversized, that would have lit something up well. Get it on eBay - might be worth a few quid to someone!

They don't seem to fetch a lot, so doorstop it is.

PS what dos the "auto" refer to?

 

[mwatsonxx]

PS what dos the "auto" refer to?

It means the output voltage is infinitely variable, rather than fixed or a selection of voltage outputs that have to be individually hard wired. For for this reason they are considered unsafe.

 

[bernardgreen]

It means the output voltage is infinitely variable,

That is a Variable Ratio Transformer. often called a Variac, the name of a company that specialised in building veriable transformers

Not infinite, limited by the maximum and minimum of the device.

Auto transformers do not provide isolation between input and output. With careful selection and installation they are safe

 

[Roger465]

It means the output voltage is infinitely variable, rather than fixed or a selection of voltage outputs that have to be individually hard wired. For for this reason they are considered unsafe.

Wow... just read up on these things.

Scary. Recycling centre...

 

[Roger465]

With careful selection and installation they are safe

Yes... look at my original picture, and you can draw your own conclusions as to the safety of the installation

 

[mwatsonxx]

Not infinite, limited by the maximum and minimum of the device

Really, thanks for the advice.

 

[echoes]

PS what dos the "auto" refer to?

It means there is just the one winding with several (or in this case, just the one) taps.
Therefore they can be used to step-up or step-down the voltage, but they do not provide electrical isolation like a regular transformer with primary and secondary windings.

 

[Roger465]

Ummm… not strictly relevant, but as it’s my thread… could somebody please explain something to me which has always baffled me, ie what’s the difference between live and neutral? May sound stupid, but as it’s AC, surely the wires are the same, swapping roles, if you like, 50 times a second?



Discuss…

 

[Nozzle]

Last time I traded in copper, it ws £3500 per tonne. Making that tranny worth about 3k.....

 

[DetlefSchmitz]

The neutral is connected to earth at the substation. So it stays more or less at earth potential, while the live goes more positive and more negative than earth.

 

[Roger465]

The neutral is connected to earth at the substation. So it stays more or less at earth potential, while the live goes more positive and more negative than earth.

Thanks! At last I know.

 

[mwatsonxx]

I'll have a go. Think of the LIVE as a pipe connected to a generator full of ball bearings ( one behind the other) at a pressure of 240volts that are waiting to be released one at a time, or 50 per second. The NEUTRAL pipe is full of balls whose energy has already been released. With no connection between the two ( switched OFF) nothing moves.

When you switch ON, you release one ball at a time onto a "water wheel", the wheel moves one revolution in a 50th of a sec, after the balls power has been used it must now return via the neutral to the generator to be recharged and to fill the gap left by the LIVE ball.

 

[echoes]

I'll have a go. Think of the LIVE as a pipe connected to a generator full of ball bearings ( one behind the other) at a pressure of 240volts that are waiting to be released one at a time, or 50 per second. The NEUTRAL pipe is full of balls whose energy has already been released. With no connection between the two ( switched OFF) nothing moves.

When you switch ON, you release one ball at a time onto a "water wheel", the wheel moves one revolution in a 50th of a sec, after the balls power has been used it must now return via the neutral to the generator to be recharged and to fill the gap left by the LIVE ball.

I don't think that's a good explanation.

 

[mattylad]

I agree, it sounds like he was talking balls.