# Lighting Practicals



## EustaceM (May 24, 2011)

What is a practical? How does one make one? Can non lights be used on a practicals. (things such as fans, strobe lights, desk lights anything that uses electricity to be turned on by light board for a cue or part of a light cue)


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## Goph704 (May 24, 2011)

Practical - ControlBooth


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## Goph704 (May 24, 2011)

Please see above def. from Control Booth WIKI. A good way to think about lighting practicals is as any light source on stage that is not a theatrical Fixture. Lamps Sconces, and Chandeliers typically fall into this def. So what are you working on that requires a practical?


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## Les (May 24, 2011)

Strobe lights can be used as 'practicals', but generally they're used to simulate lightning, which would make them more of a Special Effect. Dimming circuits can damage the internal circuitry of a strobe light (not to mention, cause them to behave erratically at times), so we recommend connecting strobes and motorized loads (such as moving lights, mirror balls and apparently fans) to a relay module (which _is_ entirely different than a dimmer run at full or set to "non-dim").

Practicals may be so-called because the "practical" explanation for the light on stage is from that lamp right there.


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## EustaceM (May 24, 2011)

I need a practical to turn on 6 desk lamps that sit on a desk and they need to be controlled by the board (mostly separately). Is there a certain procedure to create a practical? Also I was wondering if one can hook up a small fan so that it goes on and is controlled by the light board.


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## jglodeklights (May 24, 2011)

First you will need an open dimmer for each practical that you wish to control. In this case, seven of them. You can either A. remove the Edison plug from the lamps and fan, terminate them with the correct plug for your theater, and then plug them directly into circuits, or you can B. place outlets into the set, the leads of which are terminated in the correct plug for your theater, and then plug into your circuits. If you can not remove the Edison plugs, you will need to get or make adapters that convert them into the correct plug for your theater. 

One thing to keep in mind is that you should not use fluorescent, compact fluorescent (CFL) or LED lamps in the practicals unless the ones you use are specifically designed for a dimmed power source. 

After getting power to them, you will need to patch them into channels on the board.


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## DuckJordan (May 24, 2011)

jglodeklights said:


> First you will need an open dimmer for each practical that you wish to control. In this case, seven of them. You can either A. remove the Edison plug from the lamps and fan, terminate them with the correct plug for your theater, and then plug them directly into circuits, or you can B. place outlets into the set, the leads of which are terminated in the correct plug for your theater, and then plug into your circuits. If you can not remove the Edison plugs, you will need to get or make adapters that convert them into the correct plug for your theater.
> 
> One thing to keep in mind is that you should not use fluorescent, compact fluorescent (CFL) or LED lamps in the practicals unless the ones you use are specifically designed for a dimmed power source.
> 
> After getting power to them, you will need to patch them into channels on the board.



Correct on everything but the fan, some fan motors don't like dimmed power and it may damage your fan. I'm not sure how to check to see if it would work other than to try it.


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## xander (May 24, 2011)

DuckJordan said:


> Correct on everything but the fan, some fan motors don't like dimmed power and it may damage your fan. I'm not sure how to check to see if it would work other than to try it.


It's not a matter of it working or not, it most likely will (assuming it is a 120VAC fan), the issue is that the dimmer will not like it. Most dimmers do not like inductive loads and, while it will work at first and may even get you through your run, it will damage your dimmer. An easy way to get around this if you can't get a DMX controllable fan is to use a ghost load. Two-fer a highly resistive load (e.g. an incandescent stage fixture) with the fan on the dimmer and just hide it somewhere like the dimmer room. As long as the ratio of the resistive load to the inductive load is high, the dimmer should be fine.

-Tim


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## Les (May 25, 2011)

EustaceM said:


> I need a practical to turn on 6 desk lamps that sit on a desk and they need to be controlled by the board (mostly separately). Is there a certain procedure to create a practical? Also I was wondering if one can hook up a small fan so that it goes on and is controlled by the light board.


 
Mind you, the practicals *are* the desk lamps in this case. There is no other device used to designate it as a practical. They may be nothing special, but once you connect them to a dimmer and use them on stage as part of the lighting/scenic design, they effectively become practicals. Any standard desk/table lamp with an incandescent light bulb can be connected to a dimmer; all you need is a pigtail adapter (stage pin/twistlock - edison), and as mentioned, some open dimmer channels. A stage light can be plugged in to your wall outlet at home, and a lamp at home can be connected to a dimmer channel on stage. It's pretty straight forward. 

The advice for a ghost load is good, just make sure you locate the ghost instruments in a safe place -- up out of reach and nowhere near anything combustible. In the dimmer room is good, except that depending on the fixture used, it may introduce extra heat in a temperature-sensitive area. On the end a batten, with a dark blue gel, pointed out in to the wing (or up in to the grid) would be an ideal place.


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## Dionysus (May 25, 2011)

Another option for a practical fan that I've used is to use a DMX-relay to control the fan. Most fans have innate speed control anyways, set and forget. You can get some relays for a reasonable price too. Since the fan is not on a dimmer, you won't run the risk of damaging the dimmer, because indeed the type of dimmer used in theatre HATES inductive loads.
The same process can be used for fluorescents and other things that don't like to be dimmed, and is much better than running the dimmer to 100% and 0% as I've seen done often enough.

I don't know anything about your venue but you'd need to run DMX either from a iso-splitter or say from the end of your chain to the relays (Wherever you decided to put them) and simply give them power. Plug your fan into the relay and you have a DMX controlled switch!

*dusts off hands* done and done.


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## TEarlywine (May 25, 2011)

re: DMX relays

I've used R/C Servo boards from this company with good success. Here's a 1 channel dmx relay:
Blue Point Engineering Inc. - DMX Controllers / Hardware
If you do not understand electronics or DMX, but want to try this, I suggest you consult with someone who does. YMMV


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## derekleffew (Mar 7, 2012)

TEarlywine said:


> ...If you do not understand electronics or DMX, but want to try this, I suggest you consult with someone who does. YMMV


Or buy the (albeit pricey) device premade:



Doug Fleenor Design - DMX1REL20A


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## ship (Mar 7, 2012)

Just spent half a day in taking apart a “practical.”

Some very large chandelier that was probably 20's thru 50's at best with lots of crystals, very decorative, but would cost more to fix than buy even for it’s size and actual crystal glass in use all about it. Thing came out of some hotel and was proposed for use in a tour, but as with the above, it was too far gone. Cigaratte and cigar smoke turned it mostly disgusting in color and smell, and beyond that, the whole thing would need to be taken apart in wiring it, plus cleaning beyond missing/broken pieces. Hard life probably after it was removed from the hotel hang for most of the damage. Such a thing just don’t ship well. Everyone needs a huge chandelier in stock for shows - but literally coudn't even give it away for it's condition. One of my guys at least want's its frame for some LED concept he has.

Spare parts only for other pieces or if I get creative at some point - this given lots of parts. Rare parts that might be valuable over the value of the fixture - not like I would sell. Too many tours per year come in with chandelier’s but missing a part or two. I now have spare parts - them being real parts, but replacement parts in bulk.

That plus, never taken apart an old chandelier before. Learned a lot as to how it was built should I ever need to make one or in general. Plus got some non-broken really great parts out of it.

Kind of a shame in taking apart this thing, but only hope for it to live on. Cannot in imagining the scale of why it could not be saved if for nothing else, it wasn’t just the dangle stuff broken, we are talking shaped glass on the sides of the frame also broken and inner parts. Saved for storage much of it in parts as best I can do.


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