Re: [CAD_CAM_EDM_DRO] Transformer question

JanRwl@... wrote:

> In a message dated 12-Jan-01 07:33:25 Central Standard Time,
> jvicars@... writes:
>
> > Do transformers work on a ratio of input to output, or are they strictly for
> > the rated voltages? In other words if I have a 240 to 120 step down and I
> > put 120 on the primaries will I get 60 V on the secondaries? What are the
> > practical limits to doing what I described? Thanks
> >
> Yes. However, you could NOT expect to get the full POWER through a
> transformer possible when using "rated voltage", as the CURRENT must be kept
> lower, too, as the current-handling is a function of wire-cross-section (how
> "fat" the copper is).
>
> Also, you can NOT try to put 240 V. into a winding rated for 120 V!!! That
> might work for five seconds- yes, you would expect to get twice the
> secondary voltage normal, but the NUMBER OF TURNS had been calculated for the
> design-voltage, so, doubling it would over-burden the primary, even if NO
> load, and it would likewise cook things, very-probably with undue danger to
> buildings, lungs, children, pets, and other living things!

Actually, what will happen is the magnetic circuit will saturate, and the primary
will stop being an inductor, and become a short piece of solid wire, in other
words, a short circuit. It will make loud buzzing noises and trip the circuit breaker
very quickly, in most cases. Very small transformers might cook, anything over
100 W or so will just pop a breaker.

Jon