Dimmer Buzz

I have a 8 channel 1A dimmer unit, and have some 240V Halogens and some regular 240V light Bulbs connected to it

when dimmin lights the Dimmer unit buzzes constantly, just wondering if that was normal ?

thanks

 

Yes this is very normal.

Just make sure that you use an enclosure with a door, install the enclosure in a room as far away from the living areas as possible, make sure this room has a door (keep it shut), make the room well insulated AND just as a precaution - leave the radio ON

If you follow these simple steps you will never hear a dimmer buzz again.

 

SELV Transformers

What transformer are you using for the SELV lighting?

 

Not sure why this is, while I have heard dimmers that buz (sometimes on incandescent loads, sometimes on iron core LV transformers and sometimes on electronic transformers) it is not consistant - it will happen on some channels on some dimmers on some sites. I have heard it on C-bus dimmers and wall plate mounted 'stand alone' dimmers (not all of them Clipsal either) So a couple of questions:

1. is it the same on all channels?

2. what is the max load (and how many bulbs on those channels are 240V halogen and how many standard 240V incandescents) on the channels that do buzz compared to the channels (if any) that don't?

3.What is the actual measured line voltage (I have a theory that the higher the line voltage the more likely dimmer buzzing will be) at the installation?

A couple of other factors may be:

the length and cross section of cable run between the dimmer and the load and the tightness of the windings on the small inductor toroid that each dimmer channel has as part of the EMC limiting circuit around the TRIAC.

 

Load size

I have struck this with LV lights on a 2A dimmer channel, I only connected 1 lamp just to test the operation and as it was dimmed the buzzing progressively got worse. Once I connected all 5 lamps on that channel the buzzing disapeared. Transformers were Atco Possums and the lamps were 50W LV Halogens.