KITCHEN LIGHTS HAVE POPPED! - own terminology!

[Mr Dimmer]

Another point about GU10 Mains Halogen lamps is that when they "blow" a large plasma is created which, unfortunately, will destroy the triac of a leading edge dimmer. Better quality branded lamps are protected against this phenomenon. I would suggest that you replace the lamps with brand name ones before replacing the dimmer. As a rough guide, those with ceramic, rather than glass bases are better.

John

 

[helpagal]

very interesting stuff - have just unscrewed the dimmer and seen that the rating is 250w max and this has been in operation for about 6 months - bought this from Homebase!

 

[sparkybird]

Glad to hear you're getting somewhere with your lights - see, you DIDN'T need a man!

Keep at it and you'll learn lots - esp from this lot!

SB

 

[mapj1]

Haveing removed the 250W dimmer, replace it with one with a bigger rating. Although 6*50W suggests 300W would be enough, it leaves no margin for overloads or cold inrush. (ignore the waffle about inductive phase angles, mains halogens are not particularly inductive <1uH, more , only transformer fed ones (the coil in the transformer has a leakage inductance of millihenrys))
The suggestion of using perhaps a 600W is good, if you can track one down. It will cost a little more, but the mean time to failure will be longer.

PS the cold current in a filament lamp is about 10 times when it is hot - so running at low brightness is actually more stresfull for the dimmer than at full !

 

[ban-all-sheds]

Obviously being a DIY forum you would not know to account for leading or lagging power factor as a result of the inductance of the lamps

What was that about "misleading them with gumpf"? Do inductive loads cause leading PF?

Realistically, the dimmer on this circuit would need to be rated at some 600W in order to safely and effectively operate these downlighters. Anything less will likely die in a similar time frame to this unit.

I guess it should be checked with MK to be 100% sure, but I'm 99.9% sure that the quoted rating for their intelligent dimmers is for halogen lighting.

 

[Sparky Jim]

Ban-all-sheds, the lighting is rated at 300W, if you do the clculation for this, then you relaise you need a dimmer rated at at about 490W to ensure that it will not be damaged by the loading from the lamps. Now as far as I have ever seen, the rating of dimmers tends to be 250W, 300W, 350W, 400W, 600W, 800W,1000W. Consequently the dimmer will need to be rated at 600W to take the load required. As for the MK intelligent dimmers, they are rated for Capacitive loads and Inductive loads, but they do recommend that you still apply the usual safeguards when deciding on a rating to select.

 

[helpagal]

Glad to hear you're getting somewhere with your lights - see, you DIDN'T need a man!

Keep at it and you'll learn lots - esp from this lot!

SB

No, only the advice of about 10 of you!!

Think I might just stick to an ordinary rocker switch - never used the dimmer much anyway!

Thanks everyone, nice to know I can visit this site for advice and remain anonymous - feel like such a girly sometimes!

 

[Sparky Jim]

Haveing removed the 250W dimmer, replace it with one with a bigger rating. Although 6*50W suggests 300W would be enough, it leaves no margin for overloads or cold inrush. (ignore the waffle about inductive phase angles, mains halogens are not particularly inductive <1uH, more , only transformer fed ones (the coil in the transformer has a leakage inductance of millihenrys))
The suggestion of using perhaps a 600W is good, if you can track one down. It will cost a little more, but the mean time to failure will be longer.

PS the cold current in a filament lamp is about 10 times when it is hot - so running at low brightness is actually more stresfull for the dimmer than at full !

Mapj1, the comments that you call waffle should not be ignored, that is the whole point of them being there in the first place. With regards your comments about the currents etc involved, your comments are very misleading. Further, when was the last time you saw a Transformer fed 220V Halogen?

 

[ban-all-sheds]

Ban-all-sheds, the lighting is rated at 300W, if you do the clculation for this, then you relaise you need a dimmer rated at at about 490W to ensure that it will not be damaged by the loading from the lamps. Now as far as I have ever seen, the rating of dimmers tends to be 250W, 300W, 350W, 400W, 600W, 800W,1000W. Consequently the dimmer will need to be rated at 600W to take the load required. As for the MK intelligent dimmers, they are rated for Capacitive loads and Inductive loads, but they do recommend that you still apply the usual safeguards when deciding on a rating to select.

From the MK Technical Guide, for the K1501WHILV:

60-500W (LV and mains voltage halogen 60-400W/VA)

 

[felix]

One of my dimmer switches has its own 3 amp 20mm fuse in it. The fuse carrier is barely visible in the lower edge of the switch. Just thought I'd mention that. It would be a shame to chuck a working dimmer switch in the bin.

PS: Even if it is only a popped fuse your dimmer is still too small for the load you're putting on it.

 

[kavozzy]

see, you DIDN'T need a man!

Most of us are MEN Can't vouch for "ban-all-sheds" though

 

[ban-all-sheds]

Thank God you can't is all I can say....

 

[helpagal]

Hello boys - I'm back.
One more question!
Does a rocker switch have max wattage or does it not matter - in other words, I was thinking of changing the dimmer to a chrome rocker switch so can I just go and purchase any old one or do I need to take wattage into consideration?

 

[breezer]

most are rated for 5 or 6 amps. or as you would put it (juding from your first post)

any nice shiney one will do.

but do earth it. (connect earth wire from earth termial on metal plate to metal back box)

 

[Scoby_Beasley]

If you're using halogen, you need to knock a third off its rating (400w roughly 250), I've tried to avoid this, believe me, it don't work.