Flashing downlighters

[davehurry]

I'm have a problem with my 4 kitchen downlighters, which have been in the house for at least 6 or 7 years (before we moved in).

In the last couple of months they have started to flash in a dim disco stylee before coming on properly after about 10 seconds. I believe the bulbs are 50 or 60W halogen.

They are controlled by two dimmer switches (one on each side of the room).

The dimmer switches are 400w and buzz until the lights come on properly. I did change one of the dimmer switches recently and this seemed to fix the problem for a while.

I always try to leave both dimmers on full as they really don't need to be dimmed very often in the kitchen.
Quite often one of the four lights will go out (same one) and come back on at some stage later.

Any ideas as to what is going on? It's a bit like the set of Most Haunted in my kitchen at the moment.

 

[ericmark]

Don't tell everyone they will all want this optional Christmas feature!
Quartz lamps should not be dimmed as it relies on hot quartz to reflect active material back onto element. Although dimmers will work with some inverters the whole idea of the inverter is to supply a consent power to the bulb what ever the supply voltage does. There are some old units which still use transformers but they are rare. For an inverter to work with a dimming switch the two need to be matched. Some control leading edge others control trailing edge so they must be same make.

Sometimes one is lucky and non matching units will work but even changing the bulb can upset things as the element inside the envelope of quartz is a coil so can affect the inverter.

I would suggest you change dimmer switch for standard switch.

 

[RF Lighting]

Do all the lights flash at the same time, or do they flash independantly of one another?

 

[electronicsuk]

Also worth noting that you can't have two standard dimmer switches on a two-way circuit, unless they are designed to be used this way, with one being a master and another a slave unit. Can you confirm this is the case?

 

[davehurry]

Ok thanks for the response. The lights seem to be flashing all together.
I'm not too sure about the master/slave set up - how would I know? I can switch on/off/dim from either switch but if one is turned down slightly the other won't override it and they would both need to be fully 'on' to get full brightness.

I'm tempted to ditch the dimmers altogether as I really don't need them. Would that just be a straight swap to standard switches?

ericmark: I have a feeling that these may well use transformers, could they be the wrong type - I could understand this if they went off after a long period but once 'warmed up' they all stay on except for the one which takes a breather every so often.

 

[electronicsuk]

Ok thanks for the response. The lights seem to be flashing all together.
I'm not too sure about the master/slave set up - how would I know? I can switch on/off/dim from either switch but if one is turned down slightly the other won't override it and they would both need to be fully 'on' to get full brightness.

Then it's definitely wrong. There should only be one dimmer, the other should be replaced by a two-way switch. It's also possible that both dimmers may now have been damaged.

 

[davehurry]

Thanks, that makes sense. I think the replacement dimmer is now playing up as it's buzzing when the lights are switched on and it was good as new when it was installed. The other side is not making any unusual noises. Is that just a straight swap out to a standard 2 way light switch?

 

[1john]

yep. change one dimmer to a two way switch, although you may have damaged both dimmers now

 

[davehurry]

Right. Switched noisy dimmer for a 2-way switch. Hardly a peep from the other dimmer and lights are brighter than before. One of the lights went off briefly but is working at the moment. I may even swap the other dimmer to a normal switch and see if that sorts it. but the most important thing - no more disco flashing!

Thanks for all the advice on this one, now it's off to the cellar to try and fix more dodgy lighting!