Running halogen work lights on a dimming circuit?

[JLNorthGA]

We would like to use some halogen work lights (250 W or greater) like you get from Home Depot, Lowes or wherever.
Rather than have extension cords running all over the stage, I thought about just plugging them into the lighting circuits on the Electrics above the stage. They come with clamps so they can easily be mounted on the lighting batten. I figure this would give me a LOT of light on stage - and I don't have to use the Altman Fresnel lights (with expensive bulbs). The scoops are somewhat inadequate to the task - fine for rehearsal - but not too good for fine detail work or painting.

Any particular reason why I couldn't put them on a dimming circuit? If it is a problem, I've got a couple of constant current modules.

 

[techieman33]

They'll be just fine on a dimmer, the lamps in them are same technology as any of your other stage lights. A couple things to consider though are making sure you put a safety on them when you hang them. Also make sure that you can get replacement sockets for them, we use similar work lights over the stage and I have to replace the sockets about once a year.

 

[LXPlot]

Somebody correct me if I'm wrong, but from my understanding the vast majority of incandescent type lamps should be fine on a dimmer. This includes tungsten and halogen types. Fluorescent, discharge (same thing technically as fluorescent, but...), LEDs and other varieties I may have forgotten likely cannot. Many moving lights or high powered follow spots will have discharge lamps, requiring Constant Current or Relay modules.

 

[techieman33]

You are mostly correct. I've never seen a discharge lamp that could be powered by a dimmer. However there are a few floursecent and LED fixtures that are able to be powered off of a dimmer. I don't recall seeing any theatrical LED's that were meant to be plugged into a dimmer since they are designed to handle that internally. A lot of the household LED lamps are capable of being controlled by a dimmer.

 

[chausman]

Somebody correct me if I'm wrong, but from my understanding the vast majority of incandescent type lamps should be fine on a dimmer. This includes tungsten and halogen types. Fluorescent, discharge (same thing technically as fluorescent, but...), LEDs and other varieties I may have forgotten likely cannot. Many moving lights or high powered follow spots will have discharge lamps, requiring Constant Current or Relay modules.

And, moving lights have motors/servos/other electronics that require constant power to function correctly.

 

[LXPlot]

And, moving lights have motors/servos/other electronics that require constant power to function correctly.

Yes, but some (EG VL1100) get those from a separate source of electricity and run their lamp (tungsten, in the case of the 1100) on a standard dimmer.

 

[AdamLF]

Hi JLN,

Yes you're correct; you will be able to do this! Sorry if you read my previous edit before this, for some reason I had fluorescent sources stuck in my head! You can tell what I've been doing today...

Edit:-

Do remember safety bonds when rigging!

Best,
Adam

 

[JD]

Will it work? Yes, no problem..... However......
Might be some code issues as those things are kind of cheap, especially in the plastic power cord area.

 

[LXPlot]

You are mostly correct. I've never seen a discharge lamp that could be powered by a dimmer. However there are a few floursecent and LED fixtures that are able to be powered off of a dimmer. I don't recall seeing any theatrical LED's that were meant to be plugged into a dimmer since they are designed to handle that internally. A lot of the household LED lamps are capable of being controlled by a dimmer.

I know that LEDs themselves most definitely can to some extent, but I don't think any theatrical ones can. Household ones usually can, at least from what I've seen. Some fluorescent ones can apparently operate on standard "slide" type dimmers but not on triac dimmers, as the discharge is designed to operate at different levels on a wide range of voltage, but can't take the rapid on-off pattern of a triac.

Again, this is all based off research supplemented by some experimentation - I don't pretend to have any significant level of expertise.

Will it work? Yes, no problem..... However......
Might be some code issues as those things are kind of cheap, especially in the plastic power cord area.

That's a fantastic point. I guess the lamp isn't the only thing you gotta watch for.

 

[JLNorthGA]

Thanks for the replies. So - bottom line is they would work.
JD's point about the cheap, plastic power casing is a good one. I did have a double work light with a plastic casing on the back. The switch melted - now it is stuck in the on position. It is headed for the trash heap when I can get around to it. I'll have to search for work lights without that type of switch on the back.

My big "problem" is that I have ten scoops (mostly 300 W incandescent, mogul base bulbs) pointed at the stage. Three are on the apron, four are on the first electric and three are on the second electric. Fine for rehearsal - not good for detail work on sets. I really need to supplement these lights for times when I do detail work. As I said, I usually don't want extension cords on the stage. I may buy some of the double bulb work lights at Home Depot and give them a try. They look a bit sturdier.

 

[gafftapegreenia]

Have you thought about putting a higher output lamp in the scoops? If they are mogul base they are probably good for at least 500 watts, perhaps up to 1000 depending on the model.

 

[JD]

Actually, what I had said was about the power >cord< being low-temp plastic. Fine for the light, but not something you would want to have near other fixtures.

There's a bit of a "catch 22" on that one. You could replace the cord with a high-temp whip as found on any other theatrical fixture, but in the process of modifying the unit, it then no longer has a UL rating!

And I'm not going to advise you to obtain a 500 watt outdoor halogen fixture from Home Depot for around $30 and mount it to a two-inch box with a cover plate attach a whip and a C-clamp and use that!

 

[JLNorthGA]

Have you thought about putting a higher output lamp in the scoops? If they are mogul base they are probably good for at least 500 watts, perhaps up to 1000 depending on the model.

Perhaps it is time to "polish" the inside reflectors of the scoops. They are old (30+ years) 14" or so scoops. They are getting a bit "cranky" - in that the handles aren't the best. Our scoops really aren't that good of a light source. The beam spread is quite large and the intensity falls off quickly. That's why I'm trying to figure out a "better" way. I need a bit more light to work nowadays as opposed to when I was younger - the bifocal thing.

 

[LavaASU]

Yep, I know the 500W $10-15 from Ace/Lowes/Home Depot work dandily on a dimmer. You can also gel them for short term use (gels only last 30 min to 2+ hours depending on the color)... just don't expect to get ALL the gel off . We have several that get used for anything with a massive potential for stuff to get broken.

 

[Gern]

Hi Lava ASU, what about putting a layer of HT heat shield on first, then a billowed layer of gel? I learned to layer the gel this way when using par 64's with VNSP 1200w globes. Don't let anything touch the fixture glass.

btw, I had a blast hanging with your crew @ USITT!
Cheers.