Control/Dimming Some Questions About ETC D20 Dimmer Modules

Froggy

Member
Hey everybody,

This is probably a stupid/irrelevant question...

The ETC D20 dimmer module has two separate SCRs in it. Does that mean that one module is in fact two discrete dimmers? Or is it only one dimmer per module, except in situations with dimmer doubling?

I ask this because I am trying to get a handle on how many modules we will need for a new, roughly 150 circuit, typical theatrical layout (cove, box booms, 3 electrics, balcony rail, and stage floor pockets.) Our auditorium is 50 years old next year and the electrical system really hasn't been upgraded since it was first installed, except for a new console in the early/mid 90s. (20 Dove Systems stage dimmers and Hub Electric cyc lights, borderlights, and circuit raceways.)

Thanks for the help!:cool:
 
Yes, each D20 module has two separate dimmers in it. Two SCRs, two chokes, two breakers.

Might also be time to start getting your local ETC or Strand (competition is a good thing when it comes to bids) involved. You can't just buy a new rack and install it, you have to have factory trained installers come in and hook it up.
 
An ETC D20 module is responsible for dimming two independent lighting circuits. So, a rack with 48 modules will contain 96 dimmers.

Edit: Posted concurrently with Footer. I agree with him regarding factory technicians. You're going to need them eventually, as the initial power-up of installed ETC systems must be done by an ETC technician. Not sure about Strand -- same case, probably.

By your estimate of 150 channels/dimmers, I'd see if I could stretch it a bit to 192. That would be two full racks of 96 dimmers (48 modules each). Very common configuration.
 
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Thank you all for your helpful replies. I will take your advice into consideration when we start the bidding process.

Thanks again,
Froggy
 
Suggestion: Also spec some (or many) R20 and/or CC20 modules. Eventually (or currently) you're going to want to use MLs and LEDs, and will need power for them, conveniently located at your lighting positions.

... Our auditorium is 50 years old next year and the electrical system really hasn't been upgraded since it was first installed, ...
Then you need to enlist the aid of an Electrical Engineer and Theatre Consultant. It's money well-spent.

-----

/pedantic
...The ETC D20 dimmer module has two separate SCRs in it. ...
Not exactly. The D20 module contains one dual SSR. It takes two SCRs, mounted with one inverted, to dim one AC circuit. A single channel SSR contains two SCRs. Thus the ETC D20 dimmer module actually contains four SCRs.
/pedantic
 
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If you get a chance shoot me an e-mail with your contact info. 4Wall prefers ETC for a variety of reasons but I like them because they'll do the drawings as part of the install cost, the basic design hasn't changed in 20 years, the end user can send parts in directly to get repaired which saves a ton of money on maintenance, and you can run an architectural control system with a console system seamlessly for the times you want to use the theater and don't want to bring in a board op every time you do a walkthrough or presentation. And best of all when the SCR blows you can replace it in 5 minutes for 50 bucks.

Best,
David
[email protected]
702.591.8161
 

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