RE: Inductive Load Dimming

["Mark Boyce" <mark@xxxxxxx>]

From: Dr John Tankard on 14 February 2001 15:32
>
> >As mentioned above I avoided the switched mode ps for lighting,
> > main question is do the din rail modules (LD10/11) handle
> >inductive loads?  I have three transformers on lights
100/200/300VA
> > Torodial type.
>
> Torodial transformers do not like dimming using TRIAC's
> see reply below
>
> "No, the normal torroidal transformers should not be used for
> dimming with standard dimmers. The reason is that most dimmers
> chop up the normal waveform using a triac or diac and they do
> not provide symmetrical outputs on the +ve and -ve half cycles,
> this saturates the transformer core. This could result in either
> the destruction of the transformer or a fuse.
>
> You need to check with the manufacturer to see if the output
> is symmetrical, most using microcrontrolers _should_ be ok,
> if the code is correct.


Hi all,

Ok now I am confused (Easily done :) ...

At the moment I am using an appliance module to control my
Low Voltage lighting.

I would like to be able to dim this and looking at changing the
AppModule for a LD10(11).

My question is ; what transformer should I be using ?

http://www.letsautomate.com/lvlights.htm
makes it clear
that switch mode PSUs are a no-no.  Dr John's email (above)
says that Torodials may also not be suitable.

Can anyone cast any light on this for me ? (No pun intended :)

Cheers,

Mark.
--
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It is by the beans of Java that thoughts acquire speed,
The hands acquire shakes, the shaking becomes a warning,
It is by caffeine alone I set my mind in motion.
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