Hi,
Would it be possible to run the standard UK building site stepdown
transformers in revesrse to obtain 240vac from a 110vac supply. Do these
transformers have some protection circuitry to prevent overload that might
prevent this and could the transformer be used just on it's own to obtain
the stepup required.
Probably, but you shouldn't because the output on the site transformers is
a female socket - not a male plug. That means that you could have 110v
from your supply on bare male pins - not good and not considered safe.
Also, some site transformers are fitted with protection. It could be fuses
or a circuit breaker and could be on primary, secondary or both - in
different combinations! Normally this shouldn't cause a problem as it will
be rated for the appropriate winding. There is often a thermal cutout in
the 240v winding to disconnect supply on a sustained high load. This won't
work correctly with the transformer reversed, so you may wish to either
rewire it or look at other means of additional protection if required.
Just bear in mind that a 500VA transformer that would draw 2A or so from a
240v supply will draw over 4A at 110v. Watch the incoming cable length, as
the volt drop *may* cause a problem.
Just a point - if you are wanting to do this to run 240v drills or
something on a "110v site" you may be inviting all sorts of health &
safety regulation problems. They use 110v for a good reason and won't
usually allow 240v equipment no matter how it is powered!
