I've never been fond of the GU-10 230v Halogen fitting standard, but now there are compatible LED spots on the market, I love it: No more messing around with transformers, not always compatible with dimmers and sometimes requiring a minimum load. And if it's not the transformer, it's the 12v LED spot that may not always appreciate being dimmed down.
The GU-10 fitting compatible 230v LED spots eliminated the transformer and the difficulties those bring along. On top of that, the fixtures are a little bit cheaper too. So yesterday I fitted two fixtures. They both came with three halogen spots of 50Watt each. That seemed a bit excessive, so I bought three Calex branded LED spots.
All worked fine, until this morning: The lights no longer switched off. Or it switched off 30 seconds(!) later, or it switched off an on a couple of times, stopping randomly on or off. Now I'm not new to X10 interference, but I was pretty sure I have repaired all of my Xanura module's internal power supplies. So I was postponing this elimination diagnostics for later, until I realised it may be the new LED spots themselves causing the problem. Especially because the lamp had no problems switching on, only switching off. Removing the lamps from the fixture immediately cured the problem. Putting in the three standard 50Watt halogen spots that came with the fixture did not reintroduce the problem, so the LED spots are the cause.
These LED spots too have internal switch mode power supplies. And to keep coils small, they often operate at high frequencies. So I decided to dig a little deeper and measure the radiation they produce. I was flabbergasted:
- Calex LED spot emission
- Calex - Wide spectrum.png (45.95 KiB) Viewed 21848 times
The green line indicates background noise levels with the LED spot switched off. The yellow ling indicates measured noise with the LED spot switched on, hence the difference between both lines shows the noise introduces by the LED spot.
Almost anywhere below 100MHz, it emitted well over 10dBm!
And below 10MHz it's even worse:
- Calex LED spot low emission
- Calex - Low spectrum.png (43.4 KiB) Viewed 21848 times
Under 10MHz, emission above 30dBm are no exceptions. And my measurements have very poor coupling; I'm just using an antenna to pick up the emission. If I would use conductive coupling - which I won't, because connecting my spectrum analyser to mains makes me nervous - figures would be MUCH worse.
I wonder if these lamps were ever tested for EMC requirements by CE. And I wonder if there are any less-poluting LED spots in the market. I will try to bring these back to the shop tomorrow: €15,95 is a bit too much for lamps I cannot use.
The lesson learned is: If you have an X10 installation, order your LED lamps online, so you can return them if they interfere with X10.
