Let me tell ya; when ya don’t know what yer doing ya can spend a lot of $$ and get no where
I can't figure what 0 - 10 volt dimmer to use

I purchased
CREE LED module LMH020-3000-30G9-00001TW
Forward Current:

900 mA
Forward Voltage:

34.4 V


Driven by a dimmable
CREE LMD800-0120-C2A0-7030000
Which puts out a pretty steady 56.4 VDC At 2000 mA
It calls for a 01 -10 volt dimmer

At 2000 mA I figured it could drive two of the LED modules

I figured maybe I didn’t need the dimmer
But already I see a problem 54 Volts is probably over powering the LED. But It’s the dimmer Cree recommended.

When I hook the driver up to the LED module without a dimmer It produces a lot of light and then dims to very low light. I’m wondering if this is an over voltage protection feature in the LED module

So I purchased a $67 Leutron 0 – 10 low voltage Dimmer but it seems to be the wrong thing.
It has a way more sophisticated connection format there are the two leads that ostensibly go to the PSU and then a line for the ballast and another that from the documentation appears to be connected to the mains at 120 VAC. No matter how I hook it up it does nothing to regulate the voltage of the PSU by CREE

I’ve written to CREE to ask what Dimmer to use. Nowhere in their documentations is there any such information. It's a tad frustrating. I suppose I could build a resister circuit for each LED module that drops the voltage to 34 VDC, but that's the whole reason I paid $71.00 for the bleedin stinkin PSU.

 

I'll be that going in you thought it would be the easiest thing in the world -- heel, anybody can do this stuff -- am I right?
Tell us what your original purpose was and maybe we can offer some helpful suggestions. I have to say your story is more than a bit confusing as a verbal description of what you did.

You do know that you need a control voltage (in the range [0-10] VDC) to effect the dimming operation. How were you doing that in your experiments?

 

I'll be that going in you thought it would be the easiest thing in the world -- heel, anybody can do this stuff -- am I right?
Tell us what your original purpose was and maybe we can offer some helpful suggestions. I have to say your story is more than a bit confusing as a verbal description of what you did.

You do know that you need a control voltage (in the range [0-10] VDC) to effect the dimming operation. How were you doing that in your experiments?

Well instead of designing and constructing the circuit starting with a cheap 25 dollar switching PSU and building a resistor circuit to get the voltage I needed ( something I've done before), I just bought what I imagined would be the right stuff from the manufacturer. So yah in a way, I did think it'd be almost Plug 'n Play.
What the original purpose was and remains; is to get the LED modules operating.
I didn't care about dimming. I'm planning on running the LED modules full tilt.
I'm willing to try a different Low voltage dimmer, but I don't know anything about them and don't know what sort I need.
The schematic that came with the PSU shows the putative dimmer connected to two wires (Lavender and Gray) from the PSU, and that's it for the dimmer.
On the PSU There's black and red for the power coming in. Red is neutral. I should have imagined they'd have used White or Blue&Green but I can't complain because the diagram is clear.
Then there are the color coded leads for the LED module, and happily, the conductors from the LED module are corresponding colors so I don't have to guess which is positive.
I suppose I could toss it all and go find a MEANWELL PSU that produces the voltage I need with a 2 amp capacity. They are down rated at 20% But I spent a lot for that CREE power supply and, Gosh darn it, I want to use it.

 

I'm with PappaBravo; I really don't know what you have or what your goal is. Can we start over maybe?

My confusion is in what you're referring to as a CREE (brand) LED module. Is this a light or is this a power supply, which you also called it? Why isn't this working on 120 VAC? Where's the 54 volts coming from? Are you using the power supply OUT OF an LED bulb? I don't know, but I'd imagine they're pretty "Purpose Specific" beasts. If you want to use one as a power supply for some other project, it'd be helpful to know that part of it too. My thinking is that you want a variable power supply that runs from some few low volts up to maybe 54 volts DC. Using a dimmer designed for the INPUT of this LED bulb (again I'm making some assumptions) it might not achieve your purpose. Like I said, I don't know; but perhaps dimmable LED's are dimmable because the current may be the control mechanism by which they dim it.

Clarity on what you have and what you're goal is will help us help you.

 

You have two pieces: the LED module, and the dimmer, but I think you need three. The third piece you need provides a 0-10VDC voltage to the dimmer so it can perform it's function. Seems pretty clear from the device datasheets I was able to find at Mouser.

 

You have two pieces: the LED module, and the dimmer, but I think you need three. The third piece you need provides a 0-10VDC voltage to the dimmer so it can perform it's function. Seems pretty clear from the device datasheets I was able to find at Mouser.

Yah the driver and the module Seems pretty clear to me too
The 0 -10 dimmer is the mystery. The datasheets just toss in the idea of the dimmer with no information on what sort of dimmer ya need.

The dimmer I ended up with doesn't do anything in this application.
Its a Leutron and requires two additional connections ( Probably a power source ). Of those two extra conductors The Leutron data sheet has One goes to the mains and one goes to a ballast. and there is No information on how it attaches to the "ballast."
The diagrams for the CREE driver show just two leads going to a dimmer but nowhere is any information given on what sort of dimmer they want. A simple potentiometer? A digital dimmer? Nuthin~!

 

You just don't know how LEDs work..
Back to the basics for you ..
They are not resistors or like other resistive loads..

You have an LED with a Vf of 34.4V and a max current rating of 900mA..
So you need an LED driver with a current rating of 900mA.. and if you want to run 2 in series (no you really don't) it would also need to have a DC output voltage rating of greater that 2 x 34.4V (68.8V) and it does not..

The reason its not working is because you are exceeding its capable output voltage range needs and its shutting down..
You could run 1 on that BUT..it will overheat quickly..

Thats the wrong power supply..
Its intended for LMH020-8000 series LEDs and will "cook" that 3000 series..

LMD300 power supplies is what you want if you intend to keep heading down the cree direction..
And its one power supply per LED module..

 

As for a dimmer..
You need a device which outputs a 0-10V DC signal to feed into the dimmer..
The leutron might be right.. Whats the part number..

But return the power supply and get the right one first..

However it might be nice to state your overall plans first as you can't run 2 of those anyways as the Vf is over SELV ratings and not something I would suggest for a "newbie".. and holy crap that stuff is pricey..

 

Thanks for the information. It is pricey.
The Leutron dimmer is, I think the only 0 - 10 Volt dimmer rated for LEDs that they currently have in production it's the DVSTV WH . If the Leutron is going to work in this configuration I still don't have all the stuff I need. apparently they have a thing they call a "power pack" PP-DV / PP-347H which drives the dimmer switch It's the power pack that is connected to the mains. There's a relay in it and it puts out about 24 volts DC. Nuthin' is ever simple.
I put Leutron dimmers in all over my house and and as much as I like the way they perform, I don't like how physically fragile they are.

I may actually end up with one or two of the LMH020-8000 Modules. Everything I've read on them says they should be great emitters.

 

Good luck on whatever your project is..
IMO the Cree LED module stuff is just way overpriced and not at all targeted towards homeowner projects..
There are far better ways to have dimmable LEDs in your house..