RE: STEP DOWN

[Martin Greenwood <martin@xxxxxxx>]

At 14:11 29/07/2003 +0100, Kevin Hawkins wrote:
>John - you need to couple the primary and secondary with a suitable
>capacitor such that the X10 signals can get from one side of the
transformer
>to the other. I can't remember off hand the value of the capacitor I
used
>but I could probably find out. It was just as stated on the 240V/110V
>conversion site that everyone use. (Dr Bennotto or something).  The
>capacitors must be suitably voltage rated and of course this involves
>actually tapping across the 240V/110V windings so you need to be very
>careful. In fact I think I used two capacitors in series as an added
safety
>step when I did it just in case one went short circuit. (double value).
The
>devices must be deriving their timing from the mains cycles too (most
do as
>they usually get this from zero crossing points) or you get a 50Hz / 60
Hz
>incompatibility. This is a bit of a kludge but it does work.

Maybe in theory, but I found it works fine without any coupling!!
I have various US 110V lights that run on an unmodified step-down
transformer using a 110V X10 dimmer. (The X10 transmitter is on the 240V
side)

This is the transformer I used, (there is a family of 100-600W versions)

Autotransformer, SAT 300
RS Stock No.   310-1162
Manufacturer   BLOCK

Hope this helps,

Martin