Flickering dimmers

I use 3 dimmer modules and sometimes (+/-25% of the time) when dimmed between 1 and 99% the dimmed lamps start flickering, the strange thing is they all flicker at the same frequency. The lamps are regular 220v lightbulbs and 220v halogens.
I presume it’s a problem with my mains power but is there a way to filter the flickering? I was planning to test with a UPS unit to cut the mains power and see if they keep flickering when on battery but its a bit of a job to set this up so i wanted to know if you guys had any ideas.

Thanks in advance.

Aha, and I thought I was the only one with such a problem. I’ve only one dimmer with that phenonemem. After a while when dimmed it starts to flicker, when dimming to full and back it stops but will start all over again. Didn’t had the time to have a look at it but I think it’s a software bug or maybe a hardware fault ie. the clock frequencie that isn’t stable enough.

The frequency of the oscillator of the dimmer can be changed a little by temperature.
Maybe the dimmers becomes too hot. Try to get some space around the dimmers for better air flow.

I’ll try and see if i got some extra space in my cabinet but the strange thing is, it’s worse when the front of the cabinet is removed.
If it’s a heat problem it seems the hotter the modules (i presume cooling is worse when the cabinet is fully closed) the less flicker…

I’m not sure about this but a couple of months ago i closed the cabinet and haven’t noticed the flickering since (or at least it wasn’t that bad it made me switch the lights off and on). But since I opened it back up to do some rewiring the flicker is noticeable again.

Could it be the frequency gets screwed up at let’s call it “medium hot”?

It’s most likely that it has nothing to do with temperature. For now I’ve monitored the dimmers (7 for now). Hot or cold they all do the same. What’s more remarkable is that I think when there 's a little frequencie change on the net, they start to flikker. Why do I assume that … Yesterday, preciesely at 23 o’clock it begans, now working at a power plant, I know that that the time when mostely a reasonable change happen (switching the lines in Europe in another configuration can do this, we’re talkeing about a change of some millihertz).
I don’t have a frequenciemeter to monitor this at home, but is it possible the u use a 50 Hz as a reference somewhere in the software?

I hope there will be a solution soon because whith 7 dimmers this is starting to be a problem.

Maybe Velleman tests their modules in USA : 60 Hz :question:

At this time, we do not have any experience with this problem.
Dimmers in our building do not suffer from this problem, which makes it difficult to test/simulate.
We’ll keep you informed.

One of my dimmers is on the way, I’m more and more suspecting frequencie variations, thus not just a smal drop, but real fluctuations of a few millihertz. When I got the chance, I’ll note down when one of my dimmers starts to flicker, have a look at the others and maybe have a look at the data logger at work to see what the net frequencie was doing at that time.


I have a frequency meter, I’ll try to do some logging this weekend and get back to you.


I’ve done an export of the frequency logger at work at the time hat I knew I had problems with the dimmers.
The times the the dimmers where flickering are 22, 23 and 23u45. As you can see, at those times the frequency does a relevant fast change, so I think this could be the problem causing it (btw you can all say, get a stabler frequency, but that’s an European problem and not us causing it 8) )


If you want a longer logging, mail me, I’ve got a sample every 10sec

It is normal that the frequency of the grid changes continuously between certain limits.
This is caused by the load that changes continuously, hence the generators slow down or accelerate.
(See: dynamicdemand.co.uk/grid.htm#)

In this case, we think the problem is caused by CAB signals.
(trains of bits that are transmitted by the power companies, usually at around 1KHz, for a couple of minutes)
At this time, we are experimenting with filters.
We’ll keep you informed.

The more I read about CAB (or “mains ripple injection”) signals the more I’m convinced that’s indeed the problem in my case.
Where I live (Antwerp) the CAB signals are sent at 1347Hz, this is not a multiple of 50Hz so mains zero crossing detection gets screwed up.
Most modern dimmers should have ripple control or some kind of filter to get rid of the CAB signals, Niko dimmers have them according their documentation.

Is it possible to build our own filter, because I couldn’t find designs online. We could use a power factor correction unit with capacitors but that’s going to be way to expensive…

I have exactly the same problem … I’m living in 2016 Antwerp.
Any hints are welcome, as it is anoying :frowning:

I’m starting to see a pattern here, the 3’rd who has problems lives also in Antwerp …

Same problem with me (Schilde near Antwerp)… any updates yet??

Does anybody have an idea on how to solve this issue?

At this time we do not have a solution yet.
It is difficult to test as we do not experience the problem here, there is little info available regarding the signals and it appears only a couple of minutes per day.

It seems information is scarce on this one.
I found some forumposts regarding ceiling fans that resonate due to the CAB signals. It looks like filters do exist but they are pricy and I couldn’t find any.
On the CBUS forum there where some old posts about the same problem we are having but the dimmer mentioned there is a model from before the year 2000, solution was to swap the dimmer for a newer model. So it seems most dimmer manufacturers solved the problem by using a more sofisticated zero crossing detection.
I think it is time for Velleman to take a long hard look at their dimmer design. At this time they are at least 10 years behind on the competition…
Also found this post: johnarthur.wordpress.com/2008/01/23/ripple-control-noise-suppressor/
I might give this a try using a UPS to provide clean power the moment the signals kick in.
I know it’s far fetched and overly complicated but althou Velleman is right it’s only a couple of minutes a day, it’s an extremely annoying couple of minutes.

By the way, if you guys want to test a filter design I would be happy to build and test it if you could deliver the schematics and the parts aren’t overly expensive.

I have 10 dimmers al with the Same problem lives also in antwerp
my familie lives in Turnhout 3 dimmers no problem
I dit the intstallation in turnhout and in antwerp
Any hints are welcome

Let’s kick an old topic.
Is there any progress? I’m still suffering with my “dancing” lights (and not very happy with them).
It is most likely that the cab signals are the reason of those problems. Is it possible to do some tests with filters (for Antwerp at +/- 1350Hz)? I know that Niko has placed filters inside there dimmers, but since I’m using the vmb1dm’s …

some more info about the cab signals:
frequencies (from page 22): leachy.homeip.net/velbus/lastenboek.pdf

A solution would be VERY nice!