Any ideas anyone,
I bought a couple of Wickes dimmers a couple of years ago and both have failed.
The devices seem incapable of taking the surge when the filament pops. I would have thought that the brief overcurrent event would be something catered for with these things, but apparently not the wickes units.
Has anyone any suggestions as to a bomb proof two way 240V incandescent dimmer please?
Regards
H. Neary
Not really, I had several when i was partially sighted to keep the dazzle down, and even the MK one popped when the filament went. It was always the Triac that went, a new one restoring use, but my feeling is that the room in the dimmer and lack of heat sink means the devices are only just about within specs, and hence ping at the slightest maltreatment.
Brian
On Sunday 05 January 2014 08:15 nearyh wrote in uk.d-i-y:
GET dimmers?
These can take a remote input via a momentary push-to-make switch (they sell thoses - or use a "disabled alarm" pull cord with the string changed from red to white).
I cannot answer for the longevity but they seem generally good and can handle a certain range of dimmable CFLs and LEDs despite not being fully optimised for "low voltage dimming". GET is part of Schneider Electric who are a respectible company.
That's one thing I don't like about Wickes - you don't know what you are buying.
Some Megaman low-energy lamps and dimmable through conventional dimmers:
(click on a PDF next to the bulb of your choice - there's a table showing compatibility with common dimmer brands on the UK market)
Tim Watts wrote in news: snipped-for-privacy@squidward.local.dionic.net:
I have several Varilight Touch Dimmers. They always soft-start the GU10's I have and I have never had a dimmer failure.
The remote ones can be taught to respond to any old remote you might have.
I've had some "Home Automation" touch dimmers for over 20 years, fine with incandescents, no idea if they're still in existence.
In message , Brian Gaff writes
Trips on our lighting circuit breakers are invariably traced to failed filament bulbs in bedside or table lamps. My assumption is that a broken section of filament has dropped causing an arc where the conductive support wires enter the envelope.
open em up and put in a beefier triac
It is effectively a short-circuit. You can design cheap dimmers which handle this by using higher current triacs, but as a consequence, their minimum power loading raises too. If you are into electronics, a replacement triac will cost you around
50p.
Some of the more expensive hard firing triac dimmers will stand up to this better. MK used to do one which was around the £25 mark a few years ago. It's still no guarantee of survival with a lamp pops - if your supply impedance is very low, nothing much will save the triac.
What happens as the filamant breaks is that there's a tiny spark as the ends separate. This initiates an arc, which is much lower impedance than the filament, and so very rapidly grows back in both directions until it reaches the filament supports. The arc impedance reduces as the arc current increases, and within milliseconds, it's effectively a short circuit, with the current limited only by the supply impedance. No pieces of filament need to detach, although the explosive power of the arc will sometimes blow it to pieces.
In message , Andrew Gabriel writes
Excellent explanation but it doesn't cover why the bulb orientation has an effect. True to say our hanging bulbs are being displaced by low energy types but I came to my conclusion prior to this happening.
>
An arcing filament lamp can draw 60 or 150A, no triac type dimmer can withstand that. The modern halogen-in-A-line type lamps are much worse for this.
Possible solutions are: switchbank switchbank feeding your one light, using capacitors or transformers to dim it variac
NT
Why have I never had a dimmer fail in 20 odd years? Never gone out of my way to buy expensive ones or high wattage ones. Just lucky?
Tim
Thanks to all for the help. Sorry I seem to have replied to a few individuals rather than the group. I have not used Thunderbird for news before so I have gone back to Pan.
I am going to give Derbyborns dimmers a try, I think a slow ramp may solve the problem. An filament arc couldn't pass any great current through a hot filament and hopefully a slow ramp would either have insufficient Voltage to overcome the initial break, or if the filament had started to warm prior to breaking then the resistance would be high enough to prevent damage.
That's the thinking anyway, but I may of course be wrong :-(
H. Neary
As a further point, I tried to buy a 60W candle style ES lamp, only to be told that the opaque style I wanted to replace was not supplied anymore!
I ended up buying six clear lamps. Four for immediate use and two spares [Now down to one spare after trying a bounce test on the hearth].
Why only clear? Energy saving units are opaque but not dimmable! Is this another EU directive?
H. Neary
Same here - we've three in use for 12 years. Each driving 3 arm fittings so we get through plenty of bulbs. Never had a dimmer fail (he says, expecting a phonecall from the mrs saying the dimmer has failed).
One problem we had was when we tried dimmable CFL lamps - the dimmer couldn't drive them as the minumum wattage wasn't low enough. Given dimmable LED lamps are now affordable, I'd like to try those.
Any recommendation on dimmers with very low minimum load requirements? IIRC the ones we have are 50-400W load. 3 LED lamps doesn't get close...
Darren
Because clear bulbs are decorative and there is no substitute (apart from those one with a halogen bulb stuffed inside). Pearl bulbs all have alternatives AND YOU WILL USE THEM WHETHER YOU LIKE THEM OR NOT!!!
The fact that 90% of light fitting still seem to be designed for a bulb with exactly the same light distribution as they always were and look crap with a CFL in them is of no consequence. :-(
Tim
Yes, wrong. The arc quickly moves to the 240v supports
NT
I have found that almost all lamps are available from some of the web suppliers quite competitively. Some of our fittings use about 11mm screw fittings which are unavailable in the high street. I normally buy about a dozen and put the spares on the shelf in the room which uses them.
No, but I've got an anti-recomendation of the MK K1523WHILV LED dimmer, horrid flicker at all dimming levels, the more LEDs being driven the worse it is (spec claims up to 10 LEDs), horrid flashing while adjusting the dimming level, and maximum brightness nowhere near 100% of the LEDs capability.
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