Help With Dimming a Low Voltage Transformer

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Old 04-29-10, 06:35 PM
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Help With Dimming a Low Voltage Transformer

(I'm not an electrician so bear with me as I describe this)

I wanted to install under cabinet lighting and settled on the kichler linear lighting system. I also purchased a kichler electronic 12V 150W low voltage transformer (I plan to use 10-12 10W lights). I chose the electronic transformer because I read you can "dim" this type on the 120V side.

So I purchased everything and ran a test with a lutron (incandescent) dimmer and it worked great. It wasn't perfect ... the lights turned off at about 50% of the dimmer, but from 50-100% it worked great.

I proceed to get all the track and transformer mounted and everything set up as I want it. I turn on the circuit and ... it works!

However, the dimmer doesn't work. The lights appear to be at full brightness no matter where the dimmer is set. I have no idea what could be wrong because this is exactly like my test case that worked great ... with one exception, now instead of my low voltage wire being about 2 feet it is about 20 feet. Could this be it?

Just to test I went out and got another dimmer, same brand and type, and put that in place. This time, it wouldn't even turn on, however, I detected that power was getting to the transformer, but there were no lights.

I then replaced the original dimmer and it worked like before, it turned on but no dimming.

What is going on? What am I doing wrong?

Thanks!
 
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Old 04-29-10, 07:09 PM
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Originally Posted by rjcarr View Post
(I'm not an electrician so bear with me as I describe this)

I wanted to install under cabinet lighting and settled on the kichler linear lighting system. I also purchased a kichler electronic 12V 150W low voltage transformer (I plan to use 10-12 10W lights). I chose the electronic transformer because I read you can "dim" this type on the 120V side.

So I purchased everything and ran a test with a lutron (incandescent) dimmer and it worked great. It wasn't perfect ... the lights turned off at about 50% of the dimmer, but from 50-100% it worked great.

I proceed to get all the track and transformer mounted and everything set up as I want it. I turn on the circuit and ... it works!

However, the dimmer doesn't work. The lights appear to be at full brightness no matter where the dimmer is set. I have no idea what could be wrong because this is exactly like my test case that worked great ... with one exception, now instead of my low voltage wire being about 2 feet it is about 20 feet. Could this be it?

Just to test I went out and got another dimmer, same brand and type, and put that in place. This time, it wouldn't even turn on, however, I detected that power was getting to the transformer, but there were no lights.

I then replaced the original dimmer and it worked like before, it turned on but no dimming.

What is going on? What am I doing wrong?

Thanks!
You mentioned a lutron incadesant dimmer. I believe you need to be using an electronic low voltage dimmer switch.

Electronic Low Voltage Dimmers
 
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Old 04-29-10, 07:15 PM
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Hi ElectricJoe-

I know low-voltage dimmers exist, but like I said, I read that for the electronic types you can use a standard (incandescent) dimmer.

I have two problems with low-voltage dimmers:

1) They are about 5-6x more expensive. Not a big deal, but they are usually $100+.

2) If I switch (and dim) the power on the 12V side won't I be wasting a lot of energy? If I have the transformer always hot on the 120V side then I'll be wasting a lot of energy even when the lights are off, right? Or am I missing something?
 
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Old 04-29-10, 07:26 PM
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Originally Posted by rjcarr View Post
Hi ElectricJoe-

I know low-voltage dimmers exist, but like I said, I read that for the electronic types you can use a standard (incandescent) dimmer.

I have two problems with low-voltage dimmers:

1) They are about 5-6x more expensive. Not a big deal, but they are usually $100+.

2) If I switch (and dim) the power on the 12V side won't I be wasting a lot of energy? If I have the transformer always hot on the 120V side then I'll be wasting a lot of energy even when the lights are off, right? Or am I missing something?
You are correct with being able to dim the transformer, but not with a standard dimmer. You need an electronic dimmer and it still gets connected to the 120v side of the power, not the 12v side. Yes they are more expensive, but unless you use line voltage lighting, this is your only option if you want to be able to dim.
Just curious as to were you read that you can use standard dimmers.
 
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Old 04-29-10, 07:34 PM
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Hi ElectricJoe ... if that's the case then I'll just get the low-voltage dimmer. Not being able to cut the power was a much bigger problem than the price.

As for your question, I read it in several places, something like this:

"Unlike most low voltage lighting, electronic low voltage systems are designed to work with incandescent dimmers that are less expensive than the specialty dimmers designed for low voltage loads."

I think I may have even asked kichler directly. Anyway ... I'll find a dimmer and give it a shot. Thanks for the help!
 
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Old 04-29-10, 07:46 PM
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quick question. Does your transformer put out DC or AC.. if it puts out AC than the standard dimmer should work. Did you try putting it on the low voltage side? If it puts out DC than you need an electronic low voltage dimmer..
 
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Old 04-29-10, 08:02 PM
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Hi Joe ... I honestly don't know what it puts out (and I don't have it in front of me). I thought it was AC but I'm really not sure. It isn't even listed on kichler's website and the place I got it from isn't listing the specifications.

I can't find the specs anywhere, but I can probably get them to you tomorrow. Here's essentially what I got (specs are the same, look is a bit different):

Kichler 10210BK Linear Cabinet 12 Volt / 150 Watt Electronic Transformer Black (Painted)
 
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Old 04-29-10, 08:10 PM
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Originally Posted by rjcarr View Post
Hi Joe ... I honestly don't know what it puts out (and I don't have it in front of me). I thought it was AC but I'm really not sure. It isn't even listed on kichler's website and the place I got it from isn't listing the specifications.

I can't find the specs anywhere, but I can probably get them to you tomorrow. Here's essentially what I got (specs are the same, look is a bit different):

Kichler 10210BK Linear Cabinet 12 Volt / 150 Watt Electronic Transformer Black (Painted)
Yeah that site dosent tell you much.. if you have a voltage meter you can check the output yourself.
 
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Old 04-29-10, 08:16 PM
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I'm pretty sure I remember it saying on the front of it what the output is, and I'm 90% sure it is AC. I'll confirm this tomorrow and update the thread.

Assuming that it is AC, you're saying a low-voltage dimmer wouldn't make a difference? Damn, I thought I had this solved!

Anything else it could possibly be?
 
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Old 04-29-10, 08:32 PM
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Originally Posted by rjcarr View Post
I'm pretty sure I remember it saying on the front of it what the output is, and I'm 90% sure it is AC. I'll confirm this tomorrow and update the thread.

Assuming that it is AC, you're saying a low-voltage dimmer wouldn't make a difference? Damn, I thought I had this solved!

Anything else it could possibly be?
from what i read, as long as it puts out AC, than a standard dimmer should work. I guess you could try a low voltage dimmer and always return it if it dosent work.
 
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Old 04-29-10, 08:33 PM
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Thanks for your insight ... I'll give it a try and see what happens. I'll update the thread when I have more info. Thanks again for your time!
 
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Old 05-08-10, 11:25 PM
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Hi Joe ... sorry it's taken me a while to get back, I had to order the low-voltage dimmer and it took a while to get in.

So, I hooked it up and sure enough it worked great. It dimmed the lights perfectly over the entire range of the dimmer.

HOWEVER, now the transformer is *really* loud. It makes the same buzzing sound at all dimming levels. It buzzed a little bit with the previous dimmer but now it is really noticeable. I called the dimmer manufacturer (lutron) and they said the lights probably aren't compatible with the dimmer (?!?).

So, I'm going to call the light manufacturer (kichler) and see what they tell me. Looks like I'll likely just use a switch after all this trouble!
 
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Old 05-09-10, 09:32 AM
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Originally Posted by rjcarr View Post
Hi Joe ... sorry it's taken me a while to get back, I had to order the low-voltage dimmer and it took a while to get in.

So, I hooked it up and sure enough it worked great. It dimmed the lights perfectly over the entire range of the dimmer.

HOWEVER, now the transformer is *really* loud. It makes the same buzzing sound at all dimming levels. It buzzed a little bit with the previous dimmer but now it is really noticeable. I called the dimmer manufacturer (lutron) and they said the lights probably aren't compatible with the dimmer (?!?).

So, I'm going to call the light manufacturer (kichler) and see what they tell me. Looks like I'll likely just use a switch after all this trouble!
Glad to hear it worked, but sorry about the buzzing problem. Hopefully you can get a fix for that.
 
 

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