Control/Dimming Simple lighting question...help!? Limited resources...

The entire point of the listing process is to evaluate all the ways a device can fail or be misused by the end users, and the device must be able to handle these without creating a life safety issue.

In your pendulum swing to make your point I do think you went a bit to far. I think you'd be pretty hard pressed to get a listing company or manufacture to say that their certification or testing means a device is "able to handle the misuse by end users without creating a life safety issue". Example, It is very easy for me to burn my house down and kill my family by mis-using a UL listed space heater.

I'm not saying a listed device doesn't have measures built in to help prevent life safety issues from misuse but it by no means should be said that it will protect you from misuse. I would not want anyone to presume a listed device is safe from causing injury when misused based on a statement on this forum. Which I'm sure was not your intention at all.
 
Most of the cheap ($10) 600 watt household dimmers I have taken apart contain a little TO92 style triac and the although there are no "safety" issues, will not last long if actually used to dim a 600 watt load.
There is a simple formula for figuring out heat generated by a triac: 1 watt of heat for each amp running through the unit. Basically, the junction drop voltage of a Triac is 1 volt. Put 6 amps through it and you will have a triac that is putting out 6 watts of heat. (1 x 6) Just remember how hot a 10 watt soldering iron gets! Now, some of the better household dimmers actually use an 8 to 10 amp triac that is mounted to the front aluminum and may even have a dab of heat sink compound! These are often in the $18 to $24 region. How do you know for sure? Well, short of destroying it and finding out what is inside, it's basically a game of dimmer roulette.
Ganging dimmers requires some common sense as each dimmer will be producing heat.
 
Example, It is very easy for me to burn my house down and kill my family by mis-using a UL listed space heater.

And a UL listed dimmer pack can be dropped on a person's head and kill them. I do believe his point is that when used reasonably, and according to their included instructions, they are safer.

Create something that is idiot-proof and the world will make a better idiot.

It's why dimmer packs have fuses, and modern space heaters have overheat protection. Even so, I can almost guarantee that the manual with the space heater will have 1-2 pages about what not to do with it. When you cobble together off the shelf consumer grade dimmers and try to run a 750 Watt lamp off of it, you don't get warnings. It works fine when you run it at 50% during rehearsal and melts to pieces when you get excited and turn to full during the show.
 
In your pendulum swing to make your point I do think you went a bit to far. I think you'd be pretty hard pressed to get a listing company or manufacture to say that their certification or testing means a device is "able to handle the misuse by end users without creating a life safety issue". Example, It is very easy for me to burn my house down and kill my family by mis-using a UL listed space heater.

I'm not saying a listed device doesn't have measures built in to help prevent life safety issues from misuse but it by no means should be said that it will protect you from misuse. I would not want anyone to presume a listed device is safe from causing injury when misused based on a statement on this forum. Which I'm sure was not your intention at all.
Sigh...
 
Care to explain how your example is "digitally controlled" or "servo"?
Toodleoo!
Ron Hebbard.
Originally I had planned on the thing being one of those "digital potentiometers" which could be controlled by a 555 timer modulated by a fader, but soon found that said potentiometers only come in small, low capacity packages (clearly, using a bunch of these in an array to reduce the current and Vdrop across them isn't quite affordable), which then led my search to digitally controlled variacs, which only yielded variacs with a servo installed on them.

This thread's been quite a rollercoaster ride for me, to say the least.
 
And a UL listed dimmer pack can be dropped on a person's head and kill them. I do believe his point is that when used reasonably, and according to their included instructions, they are safer.

Create something that is idiot-proof and the world will make a better idiot.

It's why dimmer packs have fuses, and modern space heaters have overheat protection. Even so, I can almost guarantee that the manual with the space heater will have 1-2 pages about what not to do with it. When you cobble together off the shelf consumer grade dimmers and try to run a 750 Watt lamp off of it, you don't get warnings. It works fine when you run it at 50% during rehearsal and melts to pieces when you get excited and turn to full during the show.

A) I agree with the point he was trying to make but to someone with a lack of common sense (and there is a lot of that going around these days) it reads otherwise so I wanted to clarify. No one should ever assume a device can protect you from being stupid.

B) To get technical- Even when using off the self components (that are listed of course) each component itself has been tested and rated and will come with warnings abound. So as long as you don't exceed the rating and instructed use for each component and properly install it can't be any less safe than another piece of equipment bought off the shelf of full compass.

TO BE CLEAR- I am not advocating the overloading of any device or component.
 
I think it's as close to an outright flame war as I've seen yet on CB.

Even so, it was still surprisingly civil...


To sum the thread up this far, I think it's safe to say we need more information on what is available in terms of power, lamp ratings, what is safe to use keeping children in mind, etc.
 
Originally I had planned on the thing being one of those "digital potentiometers" which could be controlled by a 555 timer modulated by a fader, but soon found that said potentiometers only come in small, low capacity packages (clearly, using a bunch of these in an array to reduce the current and Vdrop across them isn't quite affordable), which then led my search to digitally controlled variacs, which only yielded variacs with a servo installed on them.

This thread's been quite a rollercoaster ride for me, to say the least.

I'm confused. I can't find a reference for "the thing". If "the thing" is a dimmer, how could a "digital potentiometer" hope to handle a 600 watt load (or even a 1 watt load)? But you've already answered that question.... it can't.Part of the rollercoaster was created because you've somehow gone from the OP's starting point of switching the lights on and off with power strips to laying Romex on the floor, to servo-operated autotransformers, to digital potentiometers and 555 timers. None of which help the OP solve her problem. Just trying to make sense of your solutions.
 
I own a digitally controlled variac. I usually control it with 5 digits, although if you are talented you can get away with 2 or maybe even 1 digit.
I'm guessing all of your digits are on your same hand, right? (Or maybe left if you're ambi-digitis)
Toodleoo!
Ron Hebbard.
 
I'm confused. I can't find a reference for "the thing". If "the thing" is a dimmer, how could a "digital potentiometer" hope to handle a 600 watt load (or even a 1 watt load)? But you've already answered that question.... it can't.Part of the rollercoaster was created because you've somehow gone from the OP's starting point of switching the lights on and off with power strips to laying Romex on the floor, to servo-operated autotransformers, to digital potentiometers and 555 timers. None of which help the OP solve her problem. Just trying to make sense of your solutions.
If you wanted me to, I could explain my entire thought process (with full color Microsoft Office flowcharts included at no added charge, all compiled in a convenient PDF format), but I think we've exhausted most of the subject.

I'm guessing all of your digits are on your same hand, right? (Or maybe left if you're ambi-digitis)
Toodleoo!
Ron Hebbard.
Sometimes your jokes just make me sit back in my chair, take a deep breath, and usually slowly shake my head with a slight grin, Ron. (In a good way, don't worry)
 
If you wanted me to, I could explain my entire thought process (with full color Microsoft Office flowcharts included at no added charge, all compiled in a convenient PDF format), but I think we've exhausted most of the subject.


Sometimes your jokes just make me sit back in my chair, take a deep breath, and usually slowly shake my head with a slight grin, Ron. (In a good way, don't worry)
Ahh! The Express and I have a lot in common. 'nough said.
Toodleoo!
Ron Hebbard.
 
For me, I've seen camps with anything between laughable and seriously over-specced utility service. Either way, my personal experience with them is that it seems to be slightly on the sketchy side.
 
For me, I've seen camps with anything between laughable and seriously over-specced utility service. Either way, my personal experience with them is that it seems to be slightly on the sketchy side.
My personal experience has always been that Power, in the heart of a city or in a light industrial district, tends to be 'sketchier' then that found out in the pristine wilds. With the inconsistent draws, wave-form fluctuations due to electronics, and yes I've even had Frequency issues in one light industrial area, Camps in the country have far cleaner power by comparison.
 
Hi ktflem,
Sent you a PM.
When I see fusses, generator, and camp/kids I get nervous. Will the staging of this be indoors?
 
I own a digitally controlled variac. I usually control it with 5 digits, although if you are talented you can get away with 2 or maybe even 1 digit.
I got a similar one, but it also has a foot controller when I have to stretch to hold the clamp meter.


This thread makes me think fondly of my senior year in high school before going onto EE at a Big Ten school... glad there was no internet available to me then.
 
That things a fire waiting to happen. I tried to be as nice as possible with my comment.
Oh, come on- what could go wrong with almost no heat sinking inside an unventilated plastic box?

I used to build stuff (largely before my EE/CS days - I work full time in IT now), but cost savings was never the reason, especially since the rise of unbelievably cheap automated manufacturing where the finished product cost is often cheaper than I can buy the BOM for. Considering that a listed, safe 4-channel DMX dimmer brand new is ~$100, there's just no way to roll your own for meaningfully less, even if your time is free. There are other reasons to build stuff - which is what this guy did - but not for commercial applications, not for cost savings, and not by people with absolutely no electronics background.
 

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