RE: C-Bus and Wire-wound transformers - HELP

["Keith Doxey" <ukha@xxxxxxx>]

> -----Original Message-----
> From: Neil Ball [mailto:neilball@xxxxxxx]
>
> The LV transformer issue is a bit of a problem for dimmer
> manufacturers, in
> fact Lutron sell there own rebranded transformers which they
> guarantee won't
> buzz with their dimmers to make sure the transformer is a
> known variable in
> the problem. Even then you can get the lamp filament buzzing
> as well which
> can be just as bad!

Lutron also sell trailing edge dimmers.

In a trailing edge dimmer the power is applied at the start of the mains
cycle then removed halfway through the cycle for 50% dimming unlike a
traditional leading edge dimmer where power would be applied halfway
through
the cycle and removed at the end of the cycle.

As power is supplied with the voltage at almost zero there is no surge to
cause the buzz.

With leading edge dimmers, the suppression choke also limits the rise time
of the current, the larger the choke the slower the rise time, the less the
filaments and transformers will buzz. Unfortunately, chokes are bulky and
expensive and can also buzz themselves but normally they are located away
>from

Keith

www.diyha.co.uk
www.kat5.tv