Toroids in DMX Dimmers

[artb]

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]

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]

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]

I fully agree with what BlackCatSound said..

 

[artb]

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]

In ETC dimmers those toriods are indeed chokes.

 

[imix500]

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]

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]

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.