Clean power for LED's from a Original Strand CD80 Rack

[YMCA-TD]

I'm in a small venue just looking for a couple of 20 A constant power circuits on one of my electrics. I know that there are some new retrofit and DMX relay modules out there, but because i have a couple of spare dimmers in stock I'm wondering if there is any way to convert a Dual 2.4k pack into 2 constant power circuits just controlled by the breaker?
Is there a way to bypass the SSR and choke to give me clean power from the buss to the circuit that i could use to safely power Led's and other non-dim loads.

Additionally could anyone familiar with the original Strand CD80 Packs tell me if a Dual 2.4K NN module would work in my situation as well?

Thanks!!!

 

[Les]

I'm in a small venue just looking for a couple of 20 A constant power circuits on one of my electrics. I know that there are some new retrofit and DMX relay modules out there, but because i have a couple of spare dimmers in stock I'm wondering if there is any way to convert a Dual 2.4k pack into 2 constant power circuits just controlled by the breaker?
Is there a way to bypass the SSR and choke to give me clean power from the buss to the circuit that i could use to safely power Led's and other non-dim loads.

Additionally could anyone familiar with the original Strand CD 80 Packs tell me if a Dual 2.4K NN module would work in my situation as well?

Thanks!!!

Unfortunately, I don't think there is a modification the user can do (at least not one that is UL/insurance approved; too much risk). There are a lot of companies who service these packs and could possibly do a similar but professional-grade mod. I don't know much about the CD-80's so I'll let others chime in on the particulars. Here are a couple of links for you to start out with:

http://www.dimmer.com/

http://www.litetrol.com/

 

[JD]

Although one would think you could bypass the SSR and choke, that's not a good idea! Besides voiding out any UL or other approval for the unit, something else happens:
The "dead short" current skyrockets when you remove the choke and SSR, which both act as resistors in a dead-short scenario. Because of this, the breaker must be able to function at a higher flash current without self destructing. Constant power modules are designed with this in mind.

 

[BillConnerFASTC]

I thought their non-dim modules were dry contacts. If do, they should be fine.

 

[TCJ]

Just a termination clarification, but... wouldn't the dimmer pack use TRIACs or SCRs?

As I've always understood the terminology, SSRs only switch on and off at the zero crossings of the AC power. (Even though SSRs as I understand are typically built from FETs or IGBTs, I've always heard the integral triggering circuit monitors the AC power and only activates the FET/IGBT gate when the zero crossing is reached.) Someone please correct me if I'm wrong here.

TRIACs and SCRs can switch on at any arbitrary point, and remain on until the instantaneous "holding current" through the load drops below some very small threshold. That's what makes them work in dimmers and variable power controllers. (I know this one for sure, as I've repaired and even designed dimmers and motor speed controls that use TRIACs and SCRs.) They are my first-choice "go to" components for "phase-chopped" power control; I've always regarded SSRs as something for when you need simple on/off -- without "dimming" or "variable power" -- and when mechanical contact relays are inappropriate. (Though I've never designed anything with SSRs yet.)

 

[DavidNorth]

While a SSR can be made with a MOSFET or IGBT, most SSRs in dimming are merely a package of two back to back SCRs and they are available in zero crossing and non-zero crossing [for dimming]. SCR SSRs are a very prevalent package and are indeed what we mean when we say SSR on CB.

I think you'll find that designing with SSRs is a bit easier than SCRs as there is much less wiring to do and they are easier to mount.

Back to the OP. Are you using CD80 packs or dimmer racks. CD80 packs, that have typically 12 dimmers in them, do not have an option to make them act as a non-dim or provide constant power. CD80 racks do have some module options from Strand and Johnson Systems.

David

 

[mikeydoesstuff]

There ARE cd80 non dim cards. They're pretty simple and easy, but it would always be safest to acquire a professionally made one, rather than try to make your own. Personally I've had great luck with using them to power non dimmable items.

 

[BillConnerFASTC]

I'm confused. Is what David North (and I and I <think> many others) would call a "module" what the op YMCA-TD called a "pack" and what mikeydoestuff just called a" card"?

 

[Amiers]

Is the Test Outlet on every pack or just the big ones?

The last time I used one of these packs that was not controlled and always on.

 

[mikeydoesstuff]

I use "card" to refer to the removable/replacable "modules" in the racks. I assume a "pack" refers to the (photo above) 12 dimmer unit.

 

[Scenemaster60]

There are really only 2 safe and legal ways to do this:
1. Buy a Johnson control systems relay (c. $500) or constant power (c. $300) module that is UL listed. There MAY be other companies that make these as well, but I do not know who they are.
2. Hire an electrician to move the wiring from the circuits you want to use as constant power to a nearby branch panel with regular circuit breakers.

 

[microstar]

There are really only 2 safe and legal ways to do this:
1. Buy a Johnson control systems relay (c. $500) or constant power (c. $300) module that is UL listed. There MAY be other companies that make these as well, but I do not know who they are.
2. Hire an electrician to move the wiring from the circuits you want to use as constant power to a nearby branch panel with regular circuit breakers.

Not so sure Johnson Systems modules are "universal" for any CD-80 rack. Quote from their website: "No warranty or product return is available if these products are used, even temporarily, with any OEM controls as they are incompatible.
The inferior drive signals in certain controls may damage this equipment." Sounds like they are only useable with the Johnson Systems retrofit control electronics, which would be unfortunate.

 

[Scenemaster60]

I hadn't thought of that. However, that would only affect the relay modules. The constant power modules would have no interaction with the electronics in the rack.

 

[BillConnerFASTC]

There are really only 2 safe and legal ways to do this:
1. Buy a Johnson control systems relay (c. $500) or constant power (c. $300) module that is UL listed. There MAY be other companies that make these as well, but I do not know who they are.
2. Hire an electrician to move the wiring from the circuits you want to use as constant power to a nearby branch panel with regular circuit breakers.

If its a CD80 rack - yet to be determined - why not the non-dim module made for it - with dry contact relays? Seems perfectly legal.

 

[Scenemaster60]

If its a CD80 rack - yet to be determined - why not the non-dim module made for it - with dry contact relays? Seems perfectly legal.

I was under the (perhaps mistaken?) impression that those Strand-made modules are very difficult to find at this point in time. That's why I didn't mention them. I am certainly familiar with them since work with a number of legacy CD-80 systems that have them installed to control magnetic ballasted lighting.

 

[BillConnerFASTC]

I was under the (perhaps mistaken?) impression that those Strand-made modules are very difficult to find at this point in time. That's why I didn't mention them. I am certainly familiar with them since work with a number of legacy CD-80 systems that have them installed to control magnetic ballasted lighting.

When I googled the other day, I found them for sale from multiple dealers, to my surprise, including nn, nd, and dn. And I think literol could supply them.

 

[Scenemaster60]

When I googled the other day, I found them for sale from multiple dealers, to my surprise, including nn, nd, and dn. And I think literol could supply them.

Well, in that case, it would be my first choice.
I suppose that just enough of these systems are being taken offline right now that modules are coming onto the market!

 

[YMCA-TD]

Yes !! it is in fact A CD 80 rack populated with dual 2.4k DD modules
It has also been upgraded with JS CD 2000 with both DMX preset and analog stations. ( sorry, I was remiss for not mentioning that in my initial post.)
Of course Safety is always the overriding factor, so I am now looking for the most cost effective, option to replace 1 or 2 modules ..
Based on what i've read above it looks like a strand NN would provide safe power for my needs. Im seeing a few sources for them online, but want to be sure that would be a appropriate solution to power LED or 120v accessories. The module(s) will be single tasked to constant power usage, so I won't need a switchable dim / non dim module. Although a dmx triggered relay system sounds handy, IMO Its not really a priority for our use, as the rack room is Just off stage and and and easy to access.

Thanks again to all of you, for your response and support!

 

[STEVETERRY]

Guys, an observation:

Sometimes, the forward march of technology dictates that old equipment should be retired and replaced with new equipment that is suited to (and Listed for) the application.

Even though we have may have "clever" solutions to this problem, they might not be safe or compliant with applicable standards, as others on this thread have pointed out.

I know we generally feel poor in the theatre, but this might be one of those cases where buying new gear is the right approach. After all, LED's are not going away.

Just sayin'.

ST

 

[BillConnerFASTC]

Guys, an observation:

Sometimes, the forward march of technology dictates that old equipment should be retired and replaced with new equipment that is suited to (and Listed for) the application.

Even though we have may have "clever" solutions to this problem, they might not be safe or compliant with applicable standards, as others on this thread have pointed out.

I know we generally feel poor in the theatre, but this might be one of those cases where buying new gear is the right approach. After all, LED's are not going away.

Just sayin'.

ST

Is a true CD80 non-dim module not listed for use with LEDs? 30 years ago I put non-dimmed circuits in a lot of projects, one or two at each lighting position. I'd hate to think they were not useful for any constant load. Granted I did not envision LEDs but did assume discharge lamps, fluorescents, and effects.