electrical question...

[Aesgarth]

My dad has some LightwaveRF switches in his house, the specific one in question is this:
http://www.megamanuk.com/lightwaverf/products/dimmers/jsjslw440wh/
3 of the switches are used for ordinary downlighters and work fine, however he wants the one of them to activate some RGB LED lights. This is a problem because the switch requires a trickle current in order to activate itself, the LED driver does not allow this.

None of that is the problem, I've got around that by using an AC/AC relay to switch another supply for the driver, that works, but by itself the trickle current from the switch is enough to activate the relay. I've got around that by wiring a bulb in parallel with the relay and the switching side works fine but he doesn't want a light on in the cupboard where the relay and the LED driver live all the time the LEDs are on. So, how do i replace the bulb? can i just use a 230v resistor across the relay contacts? if so what size and spec do i need?

 

[Aesgarth]

Additional info... the switch require a trickle of around 10mA to function.

 

[the snooper]

use a more powerful driver that will pull the required 10ma

 

[Aesgarth]

use a more powerful driver that will pull the required 10ma

I'm pretty sure the driver will pull more than 10ma when on, it's powering a wifi controller and 19m of led strip lights. Wiring the driver direct to the switch doesn't work though, the switch will not power on.

 

[Aesgarth]

Just to be clear, the switch requires 10ma while off to operate the switch electronics.

 

[the snooper]

I'm pretty sure the driver will pull more than 10ma when on, it's powering a wifi controller and 19m of led strip lights. Wiring the driver direct to the switch doesn't work though, the switch will not power on.

most dimmers ive seen have seem to say 40w minimum which is going to be more near 17ma

 

[Aesgarth]

But I'd still need it to pull that much while keeping the LEDs off for it to be any use that way...

 

[the snooper]

chances are the dimmer needs a resistive load

 

[the snooper]

according to the link you put up it says its ok for LED so why isn't it workling

 

[Aesgarth]

Definitely possible. It didn't work with the driver in parallel with a normal bulb either - though i forget if that just wouldnt power up the switch or wouldn't turn on when pressed

 

[Aesgarth]

according to the link you put up it says its ok for LED so why isn't it workling

Everything ive read so far says it will work with LED bulbs - in fact it is on the other 3 buttons, but not with low voltage RGB

 

[the snooper]

Everything ive read so far says it will work with LED bulbs - in fact it is on the other 3 buttons, but not with low voltage RGB

do you have it dimming the leds now

 

[the snooper]

chances are the Led's came with a switch mode power supply if that's the case replace it with transformer based and it should be fine

 

[Aesgarth]

do you have it dimming the leds now

No. The LEDs have a wifi controller that does all the dimming and colour changing. All the wall switch has to do is switch them on.

Edit: it dims the LED gu10 downlights fine.

 

[Aesgarth]

chances are the Led's came with a switch mode power supply if that's the case replace it with transformer based and it should be fine

Looks to have a transformer in it.. not sure if that helps any though. Can't find the documentation

 

[the snooper]

View attachment 81116
Looks to have a transformer in it.. not sure if that helps any though. Can't find the documentation

yeah I would try a transformer based on it, use any that you have to hand to give it a try

 

[Aesgarth]

Sorry for the misunderstanding - that's the one currently in use. I did have a regulated 5v supply and a 5v dc relay wired up when i was testing the relay plan, that allowed the switch to power up but wouldn't reliably switch on. Also when on there was a 10 second delay between switching off at the switch and the lights going out as the power drained from the psu.

 

[the snooper]

Sorry for the misunderstanding - that's the one currently in use. I did have a regulated 5v supply and a 5v dc relay wired up when i was testing the relay plan, that allowed the switch to power up but wouldn't reliably switch on. Also when on there was a 10 second delay between switching off at the switch and the lights going out as the power drained from the psu.

yeah I guessed that was the one you are using the 10 sec delay is due to capacitors and if using to simply power the relay you don't need them just rectified, I think a transformer based system is the only way I can see it being able to switch

 

[Aesgarth]

yeah I guessed that was the one you are using the 10 sec delay is due to capacitors and if using to simply power the relay you don't need them just rectified, I think a transformer based system is the only way I can see it being able to switch

Using the AC/AC relay works, but with the relay alone the residual current for the switch is enough to switch the relay. Running a conventional bulb in parallel with the relay solves that but creates a heat and light problem. The relay is switching an additional power supply to the driver and i can get the lights on this way, but i can't have the bulb running alongside the relay in the long term.

 

[tflnemesis]

You should be able to drop a resistor in the low draw side and it shouldn't need to have a very high value but its gonna get hot! So it will need ventilation and/or a heatsink.