URGENT PLEASE HELP: FGD211 Parameters - Loud Humming!!

[dw89 8]

Hi All,

Can someone tell me what parameter changes I may need to make to stop AWFUL humming on my LED bulbs after connecting a FGD211 Dimmer?

I have three lights in series, each light has two 240v E27 6W LED Bulbs, so 6 in total at 36W. Wired directly from mains to Fibaro Dimmer and on to lights i.e. no Sx, S1, S2 used.

When hooked up normally they light fine without humming. When hooked up (singularly) to a Popp Dimmer module they faintly hum on 100% and are audible at full dim. When connected to this dimmer at 100% they hum as loud as in the Popp dimmer at FULL dim. Then when I try to dim these now at anything less than 100% it just gets to the point it's unusable.

So, I'm hoping it 'may' be something to do with the parameters. Can people tell me what to change or does this happen with LED's anyway with this DImmer? What are your experiences.

Quick replies very much appreciated as they're my main dining room lights and I'd like to get it sorted so I can wire the light back up to the ceiling!! (Just in test mode on bench at mo).

KR, Dave

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[Angelus728 0]

Hi Dave,

I had a very similar problem, except that mine was above my bed and was audible only when the dimmer was off. It drove me crazy and my electrician told me that it is common, due to 'high speed switching' (whatever that means). Unfortunately, he said it's not something that can be fixed by changing a parameter and advised to use a sponge or something to wrap up the module and the driver to minimize the noise. I put them into a small box and cut a hole for the wires and the problem went away.

Hope this helps a bit.

[Daniel.Knight 1]

Hi all,

This is a common problem with many LED lamps, but it varies wildly between manufacturers and lamp types.

Some background:

Essentially what a dimmer does is switch the lamps on and off very quickly, which causes them to output a variable amount of light based on how long they are on for on each cycle.

The Fibaro Dimmer is what's know as 'Leading Edge', which means it chops off the front half of the AC waveform. I would imagine that your Lamps have integrated Electronic Low Voltage Transformers, which can be ill suited for use with leading edge dimmers. This is because the fast switching on the 'leading' edge of the waveform causes a sharp increases in voltage, and in turn the lamps draw an inrush of current, in some cases above what they are rated for.

So, imagine this process happening 100+ times a second - that's where your noise is coming from. Unfortunately not something that be fixed in the software.

Why the noise level is different between the two products is hard to say - without seeing the Popp dimmer it's hard to comment on it.

There are a couple of things you can try:

1.) Connect a dimmer bypass (not guaranteed to help, but can improve things in certain situations)

2.) Ensure the dimmer has both a Live and Neutral Connection, as opposed to Live only (if possible)

3.) Get lamps that are specifically designed for use with leading edge dimmers (best option.) Talk to your supplier to get some advice on this.

Regarding putting some material around the dimmer - I would generally try and avoid this as you could cause the dimmer to overheat, and subsequently fail.

I hope this helps.

Daniel