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morayfirthaudio

Dimming a 750w Bulb

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morayfirthaudio

Aye Aye :) What a cracking forum :) I stumbled upon this by accident, but I wish I found it years ago :) 

OK I digress, This is out of my remit as Im all Pro sound with a little Electrical knowledge :) But I found in an old Cupboard 2 750w Bulbs LES, These are big, so I thought about putting them in the Living room (Not On the Ceiling :) ) but as a feature because the elements are long and large, but... I want to Dim them right down so they glow and not burn my retinas out :) So it looks like Ill need a Variac to do this, but can you think of any other way?

Thanks for any help

Kindest

Glen

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Tony S

You don’t mention the voltage so I’ll assume 240V. One my best photographs is of a 300W GES lamp (please note it’s a lamp, not a bulb). To take the shot took a lot of messing about with the voltage so I used a Variac.

 

For a decorative lamp about 40W should be a reasonable light but it will be very red/orange.

 

Lamps resistance = 77Ω.

 

For 2 x 40W, 56V is required but this wouldn’t a standard off the shelf 100VA transformer. I’ll leave to you to look for something within your budget.

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Tony S

Just had wavy brain moment.

 

Connect the two lamps in series you could use a standard 240/110V transformer.

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Geoff1946

Why not a good old fashioned triac based dimmer?

 

Cold resistance is quite misleading as it changes dramatically as the lamp heats up.

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morayfirthaudio

Thanks Guys :)  Sorry I should have said its 240v, I have 2 of these Bulbs so I can use them both if need be.

Ive had a hunt on ebay for a Variac and were looking at about £150, (Thump!) so I thought if they could be wired in Series and then pop a Dimmer in place? 

The Dimmer Racks we use have a pre heat on them with a variable voltage but we cant get it up high enough to make the bulbs glow, They will glow but it needs to be pitch black so we need a tiny bit more voltage. 

So you think that a Variac is the only answer?

Thanks for all your help so far :) 

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Ardet R

If you wire the lamps in series and just use a standard 400W dimmer switch you should be OK.

Wiring them in series will dim them quite a lot and then the dimmer could be used to get the intensity you want.

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Richard-the-ninth

Have you tried a 1000w dimmer? click here

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