Dimming LED

[N49atv]

Looking at 2 things to dim. Sent an email to one manufacturer for info. See what they come up with.

What are UPB options for 1-10V LEDs? Do you have to use an ELV dimmer like pulse works to a ELV transformer?

Also anyone dimmed under cabinet LEDs? I'm looking at Dekor under cabinet lights. They have a dimmer you can buy, but id rather have control at a switch. It's a brick transformer, and by their install drawing the dimmer is downstream of the transformer, and dims the 12V output. What are the UPB options? If any

 

[tmbrown97]

There are dimmer-compatible power supplies you can buy - I forget the specifics, but that's the route to go - hopefully someone else can chime in with what to search for.

 

[Desert_AIP]

I use a SA 1140 to dim my undercabinet LEDs.
The hardwire transformer is dimmable.
The SA is specced to work with magnetic transformers.
 
The triac dimmers work by clipping the peaks of the AC waveform.
This reduces the width of the dimming region (or apparent dimming region) because as the waveform becomes flatter and flatter, the transformer gets fed a more and more DC like signal.
So at very low dimming levels, it gets a low level nearly DC signal.  At very high dimming levels the higher voltage levels are very short in duration, so the transformer DC output does not change appreciably from a moderately high dimming level.
 
 
The results, I get excellent dimming from 0 to ~35-45% (depending on load on the transformer - I have two systems setup with differnt loads). 
There is no visible difference above 45% dimming level.
So I simply recalibrated the link responses accordingly.
Full on is 45%, half bright is 22%, late night dim is 3%, etc.
 
My transformer is very lightly loaded, the effect may be better if there was a larger load on the transformer, or I had a lower wattage rated transformer.
But I tend to think it won't make much of a difference because of the waveform and the triac.

 

[fcwilt]

Here is some information about triac and the waveform at different settings:
 
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=SSE7506

 

[N49atv]

Yes I could go with a mag ballast (really a fancy transformer), and dim the input voltage.

Now how about as far as 0-10v LED fixtures? Any UPB that can directly dim with 0-10v signal. I have not seen any. There are a few lights id love to put in garage if I could dim them. I suppose I could do a transformer and scale it 0- 10 instead of instead of 0-12

 

[fcwilt]

Faced with dimming some high power led strips I went looking for a UPD device that put out the desired 0-10v control voltage. Didn't find one (yet) but oddly enough Insteon has such a device.

 

[Desert_AIP]

I'm using these transformers.
 
http://www.environmentallights.com/led-under-cabinet-lighting/environmentallights-premium-modular-led-under-cabinet-lighting/led-drivers.html

 

[fcwilt]

Those would do the job but they are rather pricey to my way of thinking. Perhaps they are very good quality and worth every penny.
 
The units I am using are fan-less, dry/damp/wet location, voltage controlled, 24VDC, 240W and they cost $93.00. So far they have worked well but I cannot speak to long term reliability.

 

[Desert_AIP]

They are pricey, but very robust.
I'm using the 48W versions and they weigh several pounds.
They have internal protections too.

I have a bookmark on another computer (somewhere) for a less pricey dimming 24v transformer.

I also found a lower priced source for the light bars I use.

 

[Neurorad]

I also would like to dim undercabinet lights, preferrably LED.
 
(Kitchen designer suggested Task Sempria undercabinet lights.)
 
Where is the 'Interface'/transformer located?  In a kitchen cabinet?  Behind the drywall, at a junction box?

 

[fcwilt]

In my home they are located in the cabinetry over the range, housing the duct work for the range hood and in nearby closets.
 
This was all installed when the home was being built.

 

[Desert_AIP]

My transformers are hardwired and mounted at the top back of the lower cabinets so they can't be seen.
My upper cabinets go all the way to the ceiling, if you have room above your uppers, the transformers can be mounted there.
 
The wiring to the fixtures is all LV.

 

[kdub]

I've been running the transformer Desert_AIP linked for almost 3 years with an embedded Insteon In-LineLinc Dimmer and have had 0 issues. Like Frederick, I installed the transformer in the cabinet above the range hood as there's conveniently a spare outlet in there. 

 

[tmbrown97]

Forgot about that outlet - I've been leaching power for mine from the one behind the microwave but that one is even easier to get to!
 
I have my transformer on top of the cabinets.

 

[Neurorad]

Thank you very much on the range hood outlet tip.
 
I guess the location will depend on how the current under-cabinet line voltage lines are wired - not sure where the beginning of the line is located.  I will find out Monday, when demo begins.