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A question about LOR and powering LEDs


Randy

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thanks, i was not even thinking when i went in , a 33k would = a c7 light. well give and take some

does anyone know how many watts a channel needs to work correctly, just wondering

james

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cattlefarmboy wrote:

thanks, i was not even thinking when i went in , a 33k would = a c7 light. well give and take some

does anyone know how many watts a channel needs to work correctly, just wondering

james

Well, a C7 incandescant light is going to be approximately 7 Watts. Some are 5 watts. However the 33KOhm resister will consume just 1/2 watt and that is all that is needed on a channel to appear as a proper load.
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Richard, I went to your link and I see all the text and everything....except the hi-res pictures. It could be my work site is blocking them. Are they there? Thx!

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WayneKremer wrote:

Richard, I went to your link and I see all the text and everything....except the hi-res pictures. It could be my work site is blocking them. Are they there? Thx!

Wayne, thanks for the note. You should be able to see the photos but apparently you can't. That part of the message board used to be protected, but last month I allowed guest access to those messages and postings so that LOR people could simply go there and see what they want. I need to look and see what is going on by hitting to the site as a guest on a test computer.

Sorry for your inablility to see the photos for whatever reason. As far as I now, the only area of the board that is protected are things like LOR sequence locations and other areas where there are files. The only reason to not show those areas (unless guests register as a member) is to prevent search spiders from locating files.

I will come back and post when I figure it out.
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  • 1 month later...

Hi Guys,

Im a newbie to this so please go easy on me big_grin.gif

my 2009 display will be my first ALL LED display and computerizied too (LOR)

Im planning early, I know.

Im in the UK so I get to play with 240V

My question is... Has anyone driven a standard transformer from a LOR controller channel before.

I will I need some sort of suppressant over the triac (because of the transformer)

how do you think they would handle fading, shimmer and so on...?

Ive been studying your posts and i`ve decided to go full wave.

I am making most of the LED strings myself! (about 30.000 led's which is why the planning starts now)

Here in the UK Christmas lights are VERY expensive!

Im making the LED strings to run with 24V (I think its safer, and more practical)

Ive done Electronics at college so I could keep up with most of your techno talk... but it was 8 years ago so im now gonna find my books and freshen up!



Any help would be greatly appreachiated!!

oh, one last thing... Dummy loads (or Snubbers) 33K ohm for 110V (120Vrms)

Am I right in thinking 66K ohm for 240V???



Merry Christmas to all.

Trev.

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stachows wrote:

Yup... just got back from radio shack... 33K ohm, 1/2 watt resistors...

Tried 3 of them same results... They were REALLY cheap lights though... Thought if could use them with a terminator they would look OK.
I wonder if you and Richard have the same load besides these 33K 1/2W resistors. Richard was is the smallest load you have along with these resistors. Same for you stachows?

I have yet to work with a LOR controller but I am here learning all of the ins and outs of these controllers. But I do maintain Allen Bradley PLC-5 controllers with Triac out puts. I have installed IR lamps to communicate to remote devices if they are clear to proceed. And I had to install load resistors to get the output to properly turn on and off. There was a minimum current draw of like 30mA. Anything less and the triac would not work properly. I do not at this time know what the minimum current draw is for the Triacs that LOR uses.

Dan can you give us some info about the minimum value. Do you use the same Triacs in all controllers?

Thanks

Max
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There seem to be two separate solutions here. The first is to use an additional load of a 33kohm resistor (120v) or 66kohm resistor (240v) across the controller output, to ensure that the triacs always have a load. In most cases, this will ensure that the triacs turn fully off. The second point is that of using a "snubber" across the triac (from supply to output), to ensure that the triac fires correctly with small loads (typically those using LED strings). The recommendation for this is a 100 ohm resistor in series with a 100nF high voltage capacitor.

In addition, there are changes when using the controllers on 240v, such as the UK. There is a link on the board for its own dc power supply that sets either 120v or 240v, but the "kit version" of the CTB16K includes two different values of resistor that are used in series with the triac "gate" connection. The values supplied are 220 ohm for use with a 120v supply, and 330 ohm for use ith a 240v supply.

Your other point, there is no reason why a transformer would not work on the output side of the controller, as long as it is a true "wound" transformer, rather than the electronic "switched mode" type (which would only work correctly with on & off commands only). Some of the australian users (who also have 240v) are using wound transformers.

Regards,

Alan.

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Alan C wrote:

There seem to be two separate solutions here. The first is to use an additional load of a 33kohm resistor (120v) or 66kohm resistor (240v) across the controller output, to ensure that the triacs always have a load. In most cases, this will ensure that the triacs turn fully off. The second point is that of using a "snubber" across the triac (from supply to output), to ensure that the triac fires correctly with small loads (typically those using LED strings). The recommendation for this is a 100 ohm resistor in series with a 100nF high voltage capacitor.

In addition, there are changes when using the controllers on 240v, such as the UK. There is a link on the board for its own dc power supply that sets either 120v or 240v, but the "kit version" of the CTB16K includes two different values of resistor that are used in series with the triac "gate" connection. The values supplied are 220 ohm for use with a 120v supply, and 330 ohm for use ith a 240v supply.

Your other point, there is no reason why a transformer would not work on the output side of the controller, as long as it is a true "wound" transformer, rather than the electronic "switched mode" type (which would only work correctly with on & off commands only). Some of the australian users (who also have 240v) are using wound transformers.

Regards,

Alan.


Fantastic, Thanks for your help.

I am so tired of leds at the moment! This past week I must have soldered over 500 together!

They all got to be tested before they go in because 1 in every 50 is shorted out! :X

but it will be something else when its all finnished.

Ill have to post a pic of my hobby room, (it looks like Clark Griswold`s house in a small room!

Thanks for your your help Alan.

Kind Regards.

Trevor.
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Max-Paul wrote:

I wonder if you and Richard have the same load besides these 33K 1/2W resistors. Richard was is the smallest load you have along with these resistors. Same for you stachows?

Max, I have various sizes of loads. Some channels use only a single string of 70 leds, and some channels use multiple strings. The same size resistor will work regardless of the number of strings (up to the limit of the triac of course). In the 1602 controllers I have, I believe the rated output is 8 amps per channel (120vac) up to a maximum draw of 30 amps per unit. In my setup with LEDs, the max I ever draw per channel is about 1/2 amp.
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  • 4 months later...

Hello Trev.

Iam also a newbie here comming from the Netherlands. Same as with you we use 240V / 50Hz. only we have different wallsockets.

You mensioned the resistor of 66 K. I think this is incorrect. The outcom if you will use a resistor of 0,5 W will be as follow:

P=UxI=0,5 W:240 V=2,1 mA. maximum trough the resistor.

R=U:I=240 V:0,0021 A=114285 Ohm =115 K

So for the europeen voltage you have to use 115K resistor. Any lower resistor will burn out because of the power above the 0,5 Wattof the resistor itself.

By the way. Iam gone make a 48 channel christmasdisplay for 2009. Five minitrees with 3 channels each, and 3 arches 8 channels each and some spotlights. For me this will be the first time doing a christmaslight display. Probably I'm going to use one AC controller (CTB16PC kit) and two dc Controllers (CMB16D) for my lights. For the dc controler I want to use a 24Vdc power supply that will be used for the power of my total 32 channels of led strings. The rest are minilights and 240Vac rope lights. In the case of the dc controler I won't need the all of the separed transformers with the ledstrings.

What I want to know is do the dc controlers with ledstrings need a resistor also for dimming the leds? If this is the case when i made the right calculation I will need an resistor of 0,5 Ohm 0,5 W because of the 24Vdc.

But at this time I don't know where to order led strings for europe (24V)and minilights (not yet the season). I don't have the time to make them by myself, so I have to search the internet.

I would like to hear more about the using the LOR controles in the europeen country's.

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Hi

I'm in Australia - also a 240V 50Hz supply country. I've been using LOR for 5 years now, initially using the 240V boards to switch the individual transformers that are supplied with our lights (mostly 24V AC outputs), and then last year for the first time, using the DC boards to control low voltage LED strings directly. There is an Australian LOR discussion group at http://groups.google.com/group/Aussie-LOR-Users where there have been many threads about use of transformers, disabling multi-function controllers, and use of DC boards with LEDs.

With the increasing availability of LED Christmas lights, their better reliability and the improvements in the string construction techniques, I am moving more to the use of LEDs directly connected to the DC boards. We do find however, that it is often necessary to add resistors to strings and to operate from a higher DC voltage than might be expected; eg a lot of strings operating from a nominal 24V AC power pack will need around 30V DC to get an appropriate string brightness.

Have a look at our discussions at the above link. Hope this helps

Regards Geoff

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