LEDs won't turn off - Would a 31LCDA help?

After success with Philips MR16 LED bulbs, I also bought 12 x GU10 LED's to replace another two channels of lights.

They work great with one major exception - one or two lights will appear dimly lit when powered the channel is powered off. I'm using an 8 channel LE dimmer.

I knew this may happen from reading other threads on the forum, so I've added a single halogen bulb into the circuit to stop it happening for the moment.

Ideally, I'd like to have all LED bulbs in place so the lighting/look is uniform. I saw this load correction device (32LCDA) available in the UK:

http://www.laser.com/product_info.php/item/S31LCDA-Load_Correction_Device/products_id/1601

Would this help at all?

 

That is what it is supposed to do.
http://updates.clipsal.com/ClipsalOnline/Files/Brochures/A0000268.pdf
http://www.google.com.au/url?sa=t&r...wB3QSIPCv4igmM8tBKkueA&bvm=bv.105841590,d.dGY

 

Thanks for the reply. I've had a read already, but wasn't entirely sure if this was what I was after. It sounds like it could be:

I also read something about if I used this then it may push me over the 300nF capacitance limit per channel?

 

The load correction device may well help to provide a positive off state.

The dimming performance will be down to the way the GU 10 manufacturer has designed their driver circuit. My experience has been that given the limited space inside the GU10 I have not seen any GU10 "dimmable" devices dim nicely.

Of course I have only test a few dimmable GU10 and that and that was a while back so I stand corrected if there are good performing GU10 now on the market.

I recently did a bunch of research on dimmable LED downlights on the LE C-Bus dimmers. Decent dimming performance is only possible with drivers that have high quality driver designs. Part of that design is allow the dimmer to go into a positive off state, negating the need for load correction devices external to the dimmable bulb.

Fleetz

 

Thanks fleetz. I've not purchased a load correction device yet (as I don't know how to fit it). But once I've done some more reading up on how to do so then I will give it a go .

 

Hello IanCun
As far as I know 31LCDA is not going to cause any capacitance problems for your dimmer.
Maybe you are confusing 31CAP.
Do you have a link?

You would have to purchase and install a 31LCDA for each affected dimmer channel.
It makes finding some more compatible LED's look like a reasonable option.
If it was a GU10 spot fitting and I couldn't find any suitable lamps I'd seriously consider using a relay channel.
For downlights I would just ditch the GU10's or keep doing what you are now.

I have correspondence from CIS that suggests sometimes 2 or 3 31LCDA in parallel might be necessary per channel.
They didn't say what scenario but the cost of that would be absurd.

I have several 31LCDA sitting on my bench.
I've not found them useful to reduce dimmed LED flickering in several applications.
I expect they might work OK for off state glowing or flickering.

 

Thank you for the reply and apologies that I'm so late in responding!

Yes, I think I must have been getting confused as now that I've googled the 31CAP the capacitance issues are mentioned there.

I'd like to switch some of my dimmers over to a relay in time, but that's a task for another day when I've got a bit more to spend .

How would I physically wire a S31LCDA in to the circuit? Do I just add this in parallel with the load, wiring it directly in to the dimmer unit (i.e. 2 live and 2 neutral wires for that channel, one pair for the LEDs and another pair for the 31LCDA)? I doubt I'd find an electrician familiar with CBUS near me, so I'm happy to tackle this myself if a bit of guidance is available .

 

Hello IanCun
Maybe I didn't make it clear.
I wouldn't consider them unless there was no other option.

31LCDA is supposed to help with certain problems.
It's not cheap if you need to do a lot of channels.
Mounting them in the switchboard is going to need a bit of consideration.
Then you are stuck with electronic devices behind the panel which may or may not cause other problems in the future.

I'm sure you could talk to local suppliers and find suitable replacement LED fittings just maybe not GU10.

If you go ahead with 31LCDA I suggest to have it installed by an electrician.
The installation instructions have a wiring diagram.

 

Sadly I don't think I've got any other options at the moment, as I can't afford to replace all of the dimmer units with relays and I've already got a large number of Philips dimmable bulbs in. However, it's only a few channels that have LEDs connected so the cost of the 31LCDA is a very cheap possible solution.

I've had a 31LCDA delivered in the past few days, but I'd ideally like to test it if it's not possible to fit myself. I had a look at the installation instructions that came with it and it says to add the device in parallel across the load.

I guess it isn't possible to fit the 31LCDA in to the existing consumer unit with the dimmer in it, but if I were to test it on the current setup would I be correct in thinking that I can add the 31LCD across the load by connecting one end to the Neutral Busbar at the top of the enclosure then use a chocbloc to combine the Live wire from the LEDs, C-Bus Channel and the 31LCDA?

Here's a photo of the setup, and a diagram to illustrate the way I was going to test to see if it works. Does the diagram look correct? I know that if I call a local electrician out, they'll be at a loss - as we've had the same problem before when discussing it (hence the reason I got stuck in).

 

How to go about getting my hands on the lcda

Hi There

i need to get my hands on one of these lcda units .

our local schneider branch here in cape town south africa does not seem to know anything about this product .

how can i go about getting them to bring in a couple of these units or should i just go ahead and attempt to order it online somewhere and dhl it ?


i have a few installations where i am stuck with the problem of led lamps staying dimly lit when the channel is turned off on the dimmer .

thanking you in advance

 

I can't help with how you can obtain one, however I have solved some LEDS not switching off by putting a capacitor in parallel with the LED load.

Clipsal make a part called a 31CAP which is just a 330 nano farad capacitor. I have found that a 100 nano farad capacitor is sufficient in my case.

IMPORTANT: make sure that you use capacitors that are designed and rated for your line voltage! If you are not sure then don't do this!