Halogen downlighters - low voltage or mains?

[boyesey]

Which shall I get?
With low voltage can the transformer go in the cieling void? Will it conk out and require me to lift carpets/boards to replace it? Will it make a constant annoying huummmmmm noise?

Can any one point out the relative benefits please?

 

[ban-all-sheds]

Which shall I get?

Big debate - pros'n'cons to both - ultimately personal opinion - do a search, it's been argued over before...

With low voltage can the transformer go in the cieling void?

Yup.

Will it conk out and require me to lift carpets/boards to replace it?

Yup.

But not very frequently if you toss away the C&N one that comes with the lights and buy a decent one.

Will it make a constant annoying huummmmmm noise?

Cheap and/or inappropriately dimmed ones will. Avoid both those problems and you should be fine.

Can any one point out the relative benefits please?

Big debate - pros'n'cons to both - ultimately personal opinion - do a search, it's been argued over before...

 

[basic]

the transformer can be put into the ceiling void, if it conks out you can just replace it by pulling it out via the light fitting after taking the appropiatte safety steps.
The transformer won't buzz unless its broken, even then unlikely to buzz more likely to simply not work.

When putting it into the ceiling void leave a little slack so as to replace if necessary.

Remember Part P

 

[Big_Spark]

Which shall I get?
With low voltage can the transformer go in the cieling void? Will it conk out and require me to lift carpets/boards to replace it? Will it make a constant annoying huummmmmm noise?

Can any one point out the relative benefits please?

As has been said above, these lights are designed to fit in the cieling void so the answer is Yes to that.

Each light is usually put on it's own Tx, most people use the cheapest and thus electronic type and these do not Buzz, however a lamp failure can take them out in pretty short order unless you plumb for the more costly varients from Aurora or Illuma, however you would be better off with 60va Wound core transformers, these may cost a little more, but will last decades (not an exageration). These small indiviual ones do not produce any hum as they are sealed units in epoxy with PVC casings.

The most likely cause of hum is going to be cheap dimmer switches if installed. Should you decide to go the dimmer option, then buy a good quality dimmer rated correctly for this type of load, MK make a fine range.

The Pro's and Con's of 230V GU10 lamps against 12V GU5.3 units is largely subjective, the performance of the lamps is almost identical across all manufacturers, and in practise both perform equally, although the GU10 lamps do produce a slightly different light from 12V versions so they appear slightly dimmer to the human eye.

For dimming, GU10's (230V) do have the advantage over 12V lamps and there is no problem of compatability between the dimmer and the Tx, but other than that they are generally equal, although my personal fav is the 230V GU10's except on tracks where I think think the 12V's both perform better and are inherently safer.

 

[ban-all-sheds]

Another point in favour of GU10s is that you can get LED lamps, and they are getting better all the time.

Even if you don't use them normally, you can go mad at Christmas with colour changing ones....

 

[securespark]

Osram Halotronic trannies (I've got that b****y Osram hat on again!) are very good. I've never had one fail, and have so far installed in excess of 100, some being in use for 2+ years now.

 

[Big_Spark]

Simon, the key to their success lies in the fact that like the better Aurora and lluma units they are hybrids. The voltage is actually reduced using a coil rather than pure electronic means, however they then utilise some clever electronic circuitry to stabilise the output so it remains constant at 12V even though the mains fluctuates, they also prevent surges from lamp failures that trip breakers and destroy lesser units.

Clever bits of kit, but I still personally prefer the coild of wire on their own..spose I'm getting a bit old fashioned

 

[ban-all-sheds]

Somwhere I've got a monster of a wirewound lighting transformer. I liberated it during an office refurb - from memory it has 6 or 8 individually fused outlets, it's the size of a large shoebox, and there is no way you could have it in a ceiling void (unless you fixed it to the joists).

 

[breezer]

dont tell me it sits there collecting dust "just in case you need one" tlc supply one with 6 fused ourputs

 

[plugwash]

afaict lighting "transformers" provide isolation which means that there must be some form of transformer in the design somewhere.

I think the way they get away with very tiny actual transformers is to keep the switching frequency high.

 

[delmel]

FWL you must be old school tp prefer the wire wound toroidal transformers. They are very good but not more expensive if you are comparing it to a decent electronic transformer like Mode or IBL which in my opinion are amongst the best without doubt.

GU10 do appear different than low voltage. This is because they are, infact lumen for lumen output they are around 3 times less output at worktop level from a standard height celing.

Low volt every time.

Buzzing can come from many souces. These can be dimmers, all transformers do buzz but good ones you do not hear. also cheap lamps and fittings being loose cause a buzz to. Everything gives of a resignance even if the human ear does not always hear it.

 

[felix]

Since nobody seems to have picked this up yet ---

Halogen bulbs do not take kindly to being dimmed. If you do a search you'll find long running arguments over this. The gist of it all is that the halogen is put in there for a reason, namely to pick up tungsten from the envelope, which is b****y hot, and return it to the filament, which is many times hotter. If you dim the bulb too much this won't work.

FWL_Engineer isn't the only one who prefers 'real' transformers. The modern toroidal core transformer is much smaller than its rectangular predecessor but works just as well. The external magnetic field is less and so is the noise.

Plugwash, you are correct. They rectify the incoming 50Hz supply then chop it up again at a high frequency. This allows the use of a very small isolating transformer. Another advantage is that the things will run on a wide range of voltages and frequencies - including DC. The drawback is that there are many more bits inside to go wrong and, unlike simple coils on an iron core, these bits are susceptible to damage from high voltage spikes - the kind you get from cable inductance and exploding halogen bulb filaments!

 

[oldfart]

boyesey,
If you,ve got rooms above, you may want to consider fitting "top hats" over your light fitting, these are designed to allow the heat from the halogen (which gets very hot) to escape, but also in the event of fire will close down over the aperture you,ve made in the plasterboard thus restoring your half hour fire check rating.
screwfix do them