Stephensmith
Member
Would this work?
- Thread starterStephensmith
- Start date
It's the correct and legal adapter type, with a big BUT.
Typically, the stage pin receptacle is going to be powered from a dimmer. You would not want to be powering the new LED units from a dimmed power source, so you need to be thinking as to how to convert the dimmers to dedicated power.
So, more information is needed about your current lighting systems, dimmers (if any), type, numbers, control console, control wiring (if any, etc....
Typically, the stage pin receptacle is going to be powered from a dimmer. You would not want to be powering the new LED units from a dimmed power source, so you need to be thinking as to how to convert the dimmers to dedicated power.
So, more information is needed about your current lighting systems, dimmers (if any), type, numbers, control console, control wiring (if any, etc....
Steve is absolutely correct. Yes it'll work, but definitely look at your dimmer that the stage pins are connected to. Some of them you can assign a channel to "hot" which is what you want. Otherwise, you'll want to set that channel to 100% on whatever controller you're using, BUT you MUST be sure that it will never dim! It can fry the electronics so do so at your own risk! Keep in mind that LED pars are using much less power than conventional and you'll be able to run multiple fixtures off of a single circuit. Plus, you're going to need to run DMX up there to control them (unless you're using something with built-in wireless DMX), so it may make more sense just to be safe and run up a handful of extension cords and plug them into a couple of non-dimmed circuits.
BillConnerFASTC
Well-Known Member
There are some here who would not under any but the very worst circumstances power led units wirh power through an SCR, which is most dimmers. A failure or mistake could too easily toast the LEDs or at least their power supplies. Spend the money to rewire - if just at the rack somehow and legally - intercept the circuit and wire to a circuit breaker. And de-power the circuit during periods of non-use.
Depending on your dimmers, may be easy to replace a module with a dry contact relay or constant module.
Depending on your dimmers, may be easy to replace a module with a dry contact relay or constant module.
JD
Well-Known Member
Assuming it is a fairly small dimmer rack and your are totally doing away with conventionals, get an electrician to remove the rack and replace it with a circuit breaker panel. Also ask him if he will wire in a disconnect box before the panel so you can power things down when not in use. (Circuit breakers should not be used as switches.) Most of the wiring could remain as long as it is up to code.
Agreed. Many fixture manufacturers say the same thing. This is from Blizzard:
Powering Up!
All fixtures must be powered directly off a switched circuit and cannot be run off a
rheostat (variable resistor) or dimmer circuit, even if the rheostat or dimmer
channel is used solely for a 0% to 100% switch.
David
JChenault
Well-Known Member
David
This quote breaks my understanding of physics. Wondering if someone could clarify.
If by rheostat they mean a resistance plate dimmer. Why would there be an issue? Wouldn't the wave form still be a nice sine wave? ( which is what I thought the power supply in the LED objects to ).
If they mean an auto-transformer-- how could this be an issue. Again the wave form is smooth, and the power is already going through a transformer before it goes to the meter.
Or do you think they are just being sloppy with the definition or am I missing something?
( now to be fair I have not seen at resistance plat or auto transformer in a long LONG time.)
BillConnerFASTC
Well-Known Member
I was going to post same thought but have given up on the common misuse of the word "rheostat" or at least wrong connotation. Technically I suppose the slider that might control an SCR dimmer is a rheostat.
And don't ditz by omission mag amps and thyratron tube dimmers. I don't know but guessing at least the mag amp output is sinusoidal.
And don't ditz by omission mag amps and thyratron tube dimmers. I don't know but guessing at least the mag amp output is sinusoidal.
John and Bill,
I do indeed think they are being sloppy with terminology and there are dimmers that output sinusoidal waveforms that would be just fine with switch-mode power supplies, such as in LED fixtures. However, arguably, if we tell people that certain types of dimmers are ok to work with, then that means folks have to know what technology they have. We could safely assume there is an inherent risk there.
Technically, resistance dimmers, sinewave dimmers, magnetic amplifiers, auto-transformers and saturable cores are all ok. MOSFETs, IGBTs, SCRs and triacs, and thryratrons are not. How many folks are really using the former instead of the latter? Not many.
So yes, I assume they mean thyristor dimmers, in general, but the bigger [or smaller
] point here is that LED fixture manufacturers are saying don't place these on dimmers as the fixtures will fail and/or violate warranty. It's not just a purist comment from a few folks on CB, it is, as you say John, physics. And as I have often said, you pay a lot for your LED fixtures, protect your investment and put them on switched power.
Good things to point out, on the details, guys.
Thanks!
David
I do indeed think they are being sloppy with terminology and there are dimmers that output sinusoidal waveforms that would be just fine with switch-mode power supplies, such as in LED fixtures. However, arguably, if we tell people that certain types of dimmers are ok to work with, then that means folks have to know what technology they have. We could safely assume there is an inherent risk there.
Technically, resistance dimmers, sinewave dimmers, magnetic amplifiers, auto-transformers and saturable cores are all ok. MOSFETs, IGBTs, SCRs and triacs, and thryratrons are not. How many folks are really using the former instead of the latter? Not many.
So yes, I assume they mean thyristor dimmers, in general, but the bigger [or smaller
] point here is that LED fixture manufacturers are saying don't place these on dimmers as the fixtures will fail and/or violate warranty. It's not just a purist comment from a few folks on CB, it is, as you say John, physics. And as I have often said, you pay a lot for your LED fixtures, protect your investment and put them on switched power.Good things to point out, on the details, guys.
Thanks!
David
JD
Well-Known Member
There is technically a problem with even resistance, autotransformer, and pure sine dimmers. Here's why: As the voltage lowers, the pulse width of a switch-mode power supply becomes larger trying to compensate for the drop in voltage. At this happens, the driver transistor (JFET, IGBT, whatever) heats up as it is in conduction mode longer. When the voltage gets low enough, oscillation becomes unstable. A well designed supply would shut down. Unfortunately, due to cost and competition, many supplies are not designed to deal with this and may fry or flash-over the driver.
So.... Rule of thumb applies, Don't run switch-mode supplies off of a dimmer! Does your unit contain a switch-mode supply? Almost certainly. Even transformer ballasted units usually have a small switch-mode supply to power the controlling electronics.
So.... Rule of thumb applies, Don't run switch-mode supplies off of a dimmer! Does your unit contain a switch-mode supply? Almost certainly. Even transformer ballasted units usually have a small switch-mode supply to power the controlling electronics.
Agreed. Sorry....was assuming that they were being used at full, BUT, this is yet one more reason not to assume you know what you are doing based on the dimming technology installed in the building.
David
David
BillConnerFASTC
Well-Known Member
"Technically, resistance dimmers, sinewave dimmers, magnetic amplifiers, auto-transformers and saturable cores are all ok. MOSFETs, IGBTs, SCRs and triacs, and thryratrons are not. How many folks are really using the former instead of the latter? Not many."
First, I was being a little facetious and academic at the same time. Second, I understand why thyratrons are in the second group but honestly, I suspect more people using auto transformers than thyratron. I kind of wonder if anyone is using thyratron. I've used two in my lifetime but not for a long time - Bates College and the Yale Ex - and saw and talked about Dartmouth's. Could be one running somewhere, probably not the US. I sure would hate to have to source a tube today. Mag amps must be similarly just about extinct - though they would work for ever if allowed. AMazing how robust coils of coper wire are and how unlikely to fail.
Were I doing a limited run with some LEDs in a house with auto-transformers - I wouldn't hesitate much to figure out how to physically "lock" that handle at full for that event. Otherwise, get the wiring done - which is what I said up top.
"However, arguably, if we tell people that certain types of dimmers are ok to work with, then that means folks have to know what technology they have. We could safely assume there is an inherent risk there." Agree but also risk in not explaining and allowing people to remain uninformed. I kind of like to lay it all out there.
First, I was being a little facetious and academic at the same time. Second, I understand why thyratrons are in the second group but honestly, I suspect more people using auto transformers than thyratron. I kind of wonder if anyone is using thyratron. I've used two in my lifetime but not for a long time - Bates College and the Yale Ex - and saw and talked about Dartmouth's. Could be one running somewhere, probably not the US. I sure would hate to have to source a tube today. Mag amps must be similarly just about extinct - though they would work for ever if allowed. AMazing how robust coils of coper wire are and how unlikely to fail.
Were I doing a limited run with some LEDs in a house with auto-transformers - I wouldn't hesitate much to figure out how to physically "lock" that handle at full for that event. Otherwise, get the wiring done - which is what I said up top.
"However, arguably, if we tell people that certain types of dimmers are ok to work with, then that means folks have to know what technology they have. We could safely assume there is an inherent risk there." Agree but also risk in not explaining and allowing people to remain uninformed. I kind of like to lay it all out there.
No doubt. I think it's interesting to see where some of these threads lead us. I'm game to talk about all these things as long as everyone else is.
David
David
Dionysus
Well-Known Member
How many times have I heard the question or
ABSOLUTELY David! Dimming Amplifiers anyone?
Anyways this question has come up a lot with people trying to transition into LED lighting, and not wanting to pay for the proper infrastructure. Too many don't think of the infrastructure as part of the cost of the transition, only the fixtures themselves.
I know around here there are lots of groups, including the government itself that is providing "green lighting" programs and "consultation" who really know little to nothing about stage lighting who offer government money to help your transition to LED and other "green" lighting systems. They make up reports that say the fixtures you have cost $x amount a year to run, after this conversion it will cost $y amount a year, saving you $z per year. The cost of the fixtures or lamps is this much, so it will be pay for itself in so long.... Does not include installation and infrastructure (I know because I just looked at a few of these).
At The Grand they got grants for going LED to replace all the building and house lighting that wasn't already fluorescent, which was great. That on top of installing occupancy sensors and having master control abilities of building lights (Strand a21 and such) has saved a LOT of money. I think it has finally "paid for itself".
Of course dimming the LED "retrofits" is not so nice.
A lot of old lighting fixtures were also upgraded to Source 4s, at 575w being a lot less than 1k, grant money applied to that (especially given the source 4's efficiency compared to a lot of the replaced fixtures). Meant a lighting upgrade that was long overdue for the Studio space was actually possible. The mainstage has added some LED to their rig... But are there any plans to go full LED for stage lighting? Most certainly not. It would cost far too much at the time being.
No doubt. I think it's interesting to see where some of these threads lead us. I'm game to talk about all these things as long as everyone else is.
David
ABSOLUTELY David! Dimming Amplifiers anyone?
Anyways this question has come up a lot with people trying to transition into LED lighting, and not wanting to pay for the proper infrastructure. Too many don't think of the infrastructure as part of the cost of the transition, only the fixtures themselves.
I know around here there are lots of groups, including the government itself that is providing "green lighting" programs and "consultation" who really know little to nothing about stage lighting who offer government money to help your transition to LED and other "green" lighting systems. They make up reports that say the fixtures you have cost $x amount a year to run, after this conversion it will cost $y amount a year, saving you $z per year. The cost of the fixtures or lamps is this much, so it will be pay for itself in so long.... Does not include installation and infrastructure (I know because I just looked at a few of these).
At The Grand they got grants for going LED to replace all the building and house lighting that wasn't already fluorescent, which was great. That on top of installing occupancy sensors and having master control abilities of building lights (Strand a21 and such) has saved a LOT of money. I think it has finally "paid for itself".
Of course dimming the LED "retrofits" is not so nice.
A lot of old lighting fixtures were also upgraded to Source 4s, at 575w being a lot less than 1k, grant money applied to that (especially given the source 4's efficiency compared to a lot of the replaced fixtures). Meant a lighting upgrade that was long overdue for the Studio space was actually possible. The mainstage has added some LED to their rig... But are there any plans to go full LED for stage lighting? Most certainly not. It would cost far too much at the time being.
In fairness to Ontario Hydro, subsidizing LED retrofits for theatre lighting isn't really in their best interest. Our loads are usually off-peak so it doesn't help them reduce generation and distribution costs. That said, I got Ottawa Hydro to throw their hands up in confusion and offer me a $10K subsidy by throwing spreadsheets at them until their eyes glazed over.
We solved the smoothing dimming houselight issue by leaving our incandescent system alone and installing a secondary worklight/rehearsal system using Osram Kreios FL fixtures. Our house lights are on maybe 1.5 hours per performance so the payback on smoothly dimmable LED fixtures is measured in centuries. Some day soon we'll relamp the 100W incandescents with 72W halogen bulbs and claim victory.
We solved the smoothing dimming houselight issue by leaving our incandescent system alone and installing a secondary worklight/rehearsal system using Osram Kreios FL fixtures. Our house lights are on maybe 1.5 hours per performance so the payback on smoothly dimmable LED fixtures is measured in centuries. Some day soon we'll relamp the 100W incandescents with 72W halogen bulbs and claim victory.
JD
Well-Known Member
Although we have gone a bit off topic, my own thoughts are that stage lighting loads are greatly exaggerated. People look at the maximum lighting load and forget to consider that the system is rarely run full-out, and often only a couple of hours a day. Improvements in house and general lighting are far more of a factor. External building lights, which may be on for 8 to 12 hours, changes in HVAC systems produce far more bang for the buck! We have PECO here, which has a fairly high rate. Still, a 575w S4 kept on for 2 hours costs us 18 cents. Let's say you do that for 200 days out of the year. That equals $36. So, how many years would it take to break even on upgrading it to an LED S4? If you're going to upgrade to LED, great! Just make sure you are doing it for the right reasons.
lwinters630
Well-Known Member
JChenault
Well-Known Member
I know that radio city music hall had saturable core's that were triggered with Thyratron's. USITT did a tour about 35 years ago and they were there and still working. There were landmark issues with the building so I don't know if they were able to change them or not.
They told us a story that their Thyratron's tubes needed replacement but the government had the supply locked up. They finally found that NASA had the entire supply ( NASA when asked was happy to supply some for the hall)
