Toroids in DMX Dimmers

artb · 18th June 2006, 11:55 PM

prepost warning: I might be posting a bunch of questions cause I've decided to finally start learning how to repair and upgrade the broken electronic equipment I've aquired over the years. This also inlcudes building a small workshop. As I seach more, I hope to post more.

Pardon if this should be in another section.

Why does each channel of theater dimmer have a toroid? Is it acting as an 1:1 transformer? The place where I'm interning at, a 12 channel dimmer sits at my desk. I've been able to google for info from how a DMX512 stream becomes the control for an SCR\Triac, now I'm onto the individual components in the line.

Thanks
Art

Lesson learned this weekend: Some stores will sell broken gear if you ask, thank you guitar center

Schaef · 19th June 2006, 03:08 PM

A couple of things come to mind for this.

1) They could be chokes for each channel.
2) Are you sure their supposed to put out 110? They may be 72 volt channels.

Have you thought about going to the company's website and getting the schematics? Some of the theatrical companies post the schematics online, which might help. If you're needing help finding info, post the make and model of the unit, and maybe I can help you find the info you need.

Bob

BlackCatSound · 19th June 2006, 03:10 PM

If its a big one then its a common mode choke. Dimmers make quite a lot of electrical noise.

If its a tiny little one its probably the drive for the Triac.

sivan_and · 19th June 2006, 04:51 PM

I fully agree with what BlackCatSound said..

artb · 20th June 2006, 01:44 AM

Thanks for the info. Hopefully before my intership ends I'll get to see the specs (the dimmer at my desk is what we'll be producing.) The toroids looked medium sized, which makes sense, it's a 12 channel dimmer. If you look on the ETC sensor modules they looked to be bigger, but they're two per module. Of course, I have no clue what the windings are.

Time to poke around a Bose wave radio\cd and American DJ light piece

thanks all!!
Art

alitaido · 28th June 2006, 08:14 PM

In ETC dimmers those toriods are indeed chokes.

imix500 · 28th June 2006, 08:33 PM

If the dimmer pack you have uses SCR's the chokes should be quite larger than a dimmer that uses SSR's- which is what all decent dimmers use now. SCR's are terribly noisy compared to SSR's.
If you need any, I have about 100 -20A to 50A EI core chokes pulled from a prototype colortran dimmer rack.

artb · 29th June 2006, 02:12 AM

Looks like they are chokes, according to my boss. I'm guessing a choke acts as low pass filter. What's a SSR? A quick googling brings up the chevy truck, so time for a deeper search.

thanks

imix500 · 29th June 2006, 03:27 AM

SSR is short for Solid State Relay. Ingenious devices. They crept from industrial control into theatrical dimmers just shy of two decades ago. SSR's and SCR's in particular put out lots of harmonic rich noise as the ac wave is chopped at varying points in it's cycle. So yes, it acts as a simple low pass filter.

18th June 2006, 11:55 PM	#1
artb diyAudio Member Join Date: Sep 2005	Toroids in DMX Dimmers prepost warning: I might be posting a bunch of questions cause I've decided to finally start learning how to repair and upgrade the broken electronic equipment I've aquired over the years. This also inlcudes building a small workshop. As I seach more, I hope to post more. Pardon if this should be in another section. Why does each channel of theater dimmer have a toroid? Is it acting as an 1:1 transformer? The place where I'm interning at, a 12 channel dimmer sits at my desk. I've been able to google for info from how a DMX512 stream becomes the control for an SCR\Triac, now I'm onto the individual components in the line. Thanks Art Lesson learned this weekend: Some stores will sell broken gear if you ask, thank you guitar center

19th June 2006, 04:51 PM	#4
sivan_and diyAudio Member Join Date: Dec 2004 Location: Dxb / India	I fully agree with what BlackCatSound said.. __________________ SivanandBalan

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19th June 2006, 03:08 PM	#2
Schaef diyAudio Member Join Date: Jan 2001 Location: Cuyahoga Falls, OH	A couple of things come to mind for this. 1) They could be chokes for each channel. 2) Are you sure their supposed to put out 110? They may be 72 volt channels. Have you thought about going to the company's website and getting the schematics? Some of the theatrical companies post the schematics online, which might help. If you're needing help finding info, post the make and model of the unit, and maybe I can help you find the info you need. Bob

19th June 2006, 03:10 PM	#3
BlackCatSound diyAudio Member Join Date: Oct 2004	If its a big one then its a common mode choke. Dimmers make quite a lot of electrical noise. If its a tiny little one its probably the drive for the Triac.

20th June 2006, 01:44 AM	#5
artb diyAudio Member Join Date: Sep 2005	Thanks for the info. Hopefully before my intership ends I'll get to see the specs (the dimmer at my desk is what we'll be producing.) The toroids looked medium sized, which makes sense, it's a 12 channel dimmer. If you look on the ETC sensor modules they looked to be bigger, but they're two per module. Of course, I have no clue what the windings are. Time to poke around a Bose wave radio\cd and American DJ light piece thanks all!! Art

28th June 2006, 08:14 PM	#6
alitaido diyAudio Member Join Date: Jun 2006	In ETC dimmers those toriods are indeed chokes.

28th June 2006, 08:33 PM	#7
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	If the dimmer pack you have uses SCR's the chokes should be quite larger than a dimmer that uses SSR's- which is what all decent dimmers use now. SCR's are terribly noisy compared to SSR's. If you need any, I have about 100 -20A to 50A EI core chokes pulled from a prototype colortran dimmer rack.

29th June 2006, 02:12 AM	#8
artb diyAudio Member Join Date: Sep 2005	Looks like they are chokes, according to my boss. I'm guessing a choke acts as low pass filter. What's a SSR? A quick googling brings up the chevy truck, so time for a deeper search. thanks

29th June 2006, 03:27 AM	#9
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	SSR is short for Solid State Relay. Ingenious devices. They crept from industrial control into theatrical dimmers just shy of two decades ago. SSR's and SCR's in particular put out lots of harmonic rich noise as the ac wave is chopped at varying points in it's cycle. So yes, it acts as a simple low pass filter.

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