Lamp similar to ENX

[headcrab]

Are there any MR16 lamps like the ENX, but that operate at 120V? Or is there a way to supply 82V to an ENX without a transformer?

[derekleffew]

JDR is a series (note: not a true ANSI code) of MR16, 120V lamps, available in many wattages and beam spreads.

JDR, MR16, Halogen, Light Bulbs, Lamps, E26, E17, Halopika, Display Lighting

[Les]

... is there a way to supply 82V to an ENX without a transformer?

I was about to say "no" but then I realized that I have an overhead projector that definitely has no transformer. I know there must be some component that takes its place, but it must be small and lightweight because I can't see it in there, and overhead projectors weigh nothing at all.

Maybe this will help the OP so I will ask:
What is this component called, and why don't they put them in ENX-powered followspots?

Out of curiosity, what are you working on, headcrab? I recommend using a cooling fan if you plan on using an ENX lamp.

[Lotos]

I was about to say "no" but then I realized that I have an overhead projector that definitely has no transformer. I know there must be some component that takes its place, but it must be small and lightweight because I can't see it in there, and overhead projectors weigh nothing at all.

Maybe this will help the OP so I will ask:
What is this component called, and why don't they put them in ENX-powered followspots?

Out of curiosity, what are you working on, headcrab? I recommend using a cooling fan if you plan on using an ENX lamp.

Why are projector/ spotlight bulbs 82 Volts? | Sci.Electronics.Design | Electronics-Related.com

Something about a diode inline (series, I assume) with the lamp... From what I gather.

[Lightguy5]

I have in my shop's LampLand, a couple of old Sylvania ELH 120v 300w.

[headcrab]

I'm retrofitting a projector to use a lamp other than a metal-halide source. The ballast failed, and I can't find a new one. I don't want to spend the money on either discharge or LED lamps, so I want to find a halogen lamp. I'm aware that I'll need to address cooling it.

It's my projector; I can do what I want to it.

[Les]

That's cool. Have you considered buying a used overhead on eBay and using its parts? Make sure you get one that actually uses an ENX lamp. I know that some Dukane models used a funky quartz lamp without a reflector.

[FMEng]

It isn't a ballast, it is a buck transformer. A buck transformer has only one winding, which is tapped. It's the same principal as an autoformer. The transformer's VA rating only needs to be the current times the voltage drop, not the wattage of the lamp. The overhead projectors tap the fan motor winding for their lamp, which works the same as the buck transformer. The small "device" in the projector is nothing but a thermostat to prevent overheating if the air flow is restricted.

There is nothing physically smaller that will do the job. A diode would drop the voltage to 60V and cause flicker because half the AC waveform is gone.

Since the quality of the kludge may not be important, the poor man's way to feed one of these lamps is to use a simple, residential lamp dimmer, and adjust it so that the voltage measures as ~82V with a TRUE RMS voltmeter. Whether or not it would be stable enough for the task at hand is the question.

[headcrab]

I don't have a true RMS meter. A an off-the-shelf dimmer is too big to make me happy, but I can easily make one that fits where the ballast used to be.

[headcrab]

At present I think I would need at least a 100W LED array in this projector.

[DELO72]

The lamps you are looking for (closest to an ENX-- but at 120V) are the ELH (300W, 120V GY5.3 base), or ENH (250W, 120V, GY5.3 base). BUT-- that said, I didn't check the working distance (the distance away from the reflector that the lamp comes to a focal point) on them to see if they compare. You will want to do that. If the Working distance is different, you will have focusing issues.

JDR lamps use an E17 base (intermediate Screw base) and are not an option in the same socket.