Converting my Omega D-2 enlarger to LED illumination

[ASA1000]

Here's where I'm at.
Any comments or suggestions would be greatly appreciated

[Tin Can]

I like

Good work and very clean

Thanks for posting

[sharktooth]

Very cool!

A couple of thoughts come to mind. If there are 12 units at 1 amp each, then I'm assuming this setup will be drawing 12 amps. It might cause a circuit breaker to trip if you have anything else hooked up to that circuit at the same time.

I also wonder how the fans will affect enlarger vibration. Do you turn the fans off for exposure, or leave them on? If you turn them off for exposure, how hot do things get, and how fast? I guess you'll find that out when you make some test prints. Looking forward to your results.

[ASA1000]

Very cool!

A couple of thoughts come to mind. If there are 12 units at 1 amp each, then I'm assuming this setup will be drawing 12 amps. It might cause a circuit breaker to trip if you have anything else hooked up to that circuit at the same time.

I also wonder how the fans will affect enlarger vibration. Do you turn the fans off for exposure, or leave them on? If you turn them off for exposure, how hot do things get, and how fast? I guess you'll find that out when you make some test prints. Looking forward to your results.

2.8 volts each, on a 20 amp circuit. There is no discernable vibration. I thought about plugging the fan into the satellite outlet on the timer so it goes off when the lights are on, but for now I'm going to monitor it manually.
thx!

[sharktooth]

2.8 volts each, on a 20 amp circuit.

Thanks for reminding me "gently" why I never became an electrical engineer.

[koraks]

A couple of thoughts come to mind. If there are 12 units at 1 amp each, then I'm assuming this setup will be drawing 12 amps.
12 units

It might cause a circuit breaker to trip if you have anything else hooked up to that circuit at the same time.

White LEDs, so forward voltage around 3V. At 1A that's 3W each, 12 units makes 36W. From a 110V socket that's roughly 3A without any losses; let's assume 90% efficiency in the driver (which would be abysmal), makes 3.3A. No problem at all.

No doubt the setup will work just fine. At 36W it'll take that aluminum chuck a minute or two to warm up to any appreciable temperature even without a fan. As said in the video the fan is plenty effective.

@ASA1000 if I were you I'd look into the airflow around that fan to make sure it doesn't blow any dust onto the negative stage. I'm not too concerned about vibrations; I'm running an even more challenging setup with two fairly powerful fans at pretty high speed and it doesn't cause any issues whatsoever.

This video nicely shows that a LED conversion can be easy as pie. Personally I'd have gone for a blue/green combination so there's no more need for filters, but it's more work and white LEDs and old-style filters will work fine just as well.

[sharktooth]

White LEDs, so forward voltage around 3V. At 1A that's 3W each, 12 units makes 36W. From a 110V socket that's roughly 3A without any losses; let's assume 90% efficiency in the driver (which would be abysmal), makes 3.3A. No problem at all.

No doubt the setup will work just fine. At 36W it'll take that aluminum chuck a minute or two to warm up to any appreciable temperature even without a fan. As said in the video the fan is plenty effective.

@ASA1000 if I were you I'd look into the airflow around that fan to make sure it doesn't blow any dust onto the negative stage. I'm not too concerned about vibrations; I'm running an even more challenging setup with two fairly powerful fans at pretty high speed and it doesn't cause any issues whatsoever.

This video nicely shows that a LED conversion can be easy as pie. Personally I'd have gone for a blue/green combination so there's no more need for filters, but it's more work and white LEDs and old-style filters will work fine just as well.

At least ASA1000 did it "gently". Koraks gets a 15 yard penalty for "piling on".

[ASA1000]

[QUOTE=koraks;1666064]@ASA1000 if I were you I'd look into the airflow around that fan to make sure it doesn't blow any dust onto the negative stage. I'm not too concerned about vibrations; I'm running an even more challenging setup with two fairly powerful fans at pretty high speed and it doesn't cause any issues whatsoever.

I'll have to see what happens. The enlarger is grounded, the HIVAC is humidified and I exchange the air in the room every 15 minutes...... plus I have a 25 year old Staticmaster Brush!!

[stevea]

Since everyone is piling on, I'll just note that 36W at 110V is actually 300mA, not 3A, and Ohm's law doesn't really apply since this is a non-linear circuit.

But my real question is: do you notice a delay between turning the light source on and the LEDs actually lighting? LED drivers usually use switching regulators (for efficiency) and can have a delay before the output goes live - you often see this in LED downlights, incandescent replacements, etc. I'm interested in whether this happens with these special-purpose LED drivers.

thanks

[ASA1000]

Since everyone is piling on, I'll just note that 36W at 110V is actually 300mA, not 3A, and Ohm's law doesn't really apply since this is a non-linear circuit.

But my real question is: do you notice a delay between turning the light source on and the LEDs actually lighting? LED drivers usually use switching regulators (for efficiency) and can have a delay before the output goes live - you often see this in LED downlights, incandescent replacements, etc. I'm interested in whether this happens with these special-purpose LED drivers.

thanks

It seems to be instant on, but until I have some developer and run some consistency tests, I really can't say for sure. What I do know is, after the exposure, if I touch the aluminum heat sink, the leds will glow! Understand. I'm making this up as I go along. ;-)