Wasn’t sure where to put this… I’ve been reading for days trying to figure this out on my own and having no luck.
Here’s the deal:
I have a fixture that contains 12 - 28V 250W ACL globes. The traditional way to make this thing go is to chain 4 globes each in series and run each circuit a little short of line voltage on an AC dimmer.
What I’d like to do, is run them on DC power and use some large wireless DC dimmers that I have to have individual control.
The trouble I’m running into, is that I don’t know what an appropriate PSU is to drive the dimmers. The ones that I have are from LED projects and say specifiically, “for LED loads only”.
So, primary question is, What is the right PSU for this application? The dimmers I have are 4 channel, 15A per channel max/42A total, I’ll have 4 of them that run 3 globes each. In my mind, I doubted that I could find a PSU of a high enough wattage that wasn’t out of my budget, so I’ve been focused on finding either 2 - 2000-2500W PSUs to handle two dimmers each or possibly 4 - 1000W PSUs to each handle its own dimmer.
But it’s also spawned the question of what makes the PSUs I have only suitable for LED loads. Wondering if it’s related to the current-limiting? Is there a better type of PSU to drive DC Tungsten globes? Not having these answers is part of why I am struggling to make a decision between the limited PSU options I have at those high wattages.
Any help is appreciated.
Welcome to the forum.
LED power supplies are constant current because LEDs are current, not voltage, driven devices. Standard lamps are voltage, not current driven devices.
For this application, and vast majority of other applications, you want a constant voltage power supply that has a high enough current rating to accommodate your load. Electronic current limiting is not needed in your application, ordinary fuses will suffice.
Edited to add:
Running them with the normal AC method will be more efficient yielding a lower electric bill and will cost a lot less money for the installation. (AC to DC conversion wastes anywhere from 10% to 50% of the input power on the conversion and dissipates it as heat)
Thanks for the response and for the welcome, Paul.
Does using the constant current PSUs damage them or decrease output of the luminaire?
I’ve settled on this PSU for testing:
If I end up using it, I’d get two to drive two dimmers and 6 globes each. Do you foresee any problems? I wasn’t intending to parallel them, but I’m open to the idea if there’s a benefit or a safety issue.
Efficiency is not a concern. More important, for my purposes, to have the individual control of the globes and the wireless functionality of the dimmers. The application is build the PSUs and dimmers into a mobile pack with a feeder to setup and break down for use at multiple locations.
EDIT: Also, my intention is to use the voltage trim to increase the voltage to 28V. Will that affect the lifespan of the PSU? Should I find a PSU with a native 28V output?
Can’t answer either question because I have no specs for the LED power supply, dimmers, or bulbs. Although, even with full data sheets, the questions might not be answerable since it is an unintended application for an LED power supply and some needed specs might not be in the data sheet.
Operating a 24V supply at the maximum adjustment limit of 28V might shorten the life, I would try to find a supply with more head room.