I want to motorize my grand curtain (I get bored sometimes)... It's currently manually operated with ropes.. pretty generic. Any thoughts to cheap ways to do this? Ideally something DMX or dimmer controlled would be nice (as farfetched as it is to put a motor on a dimmer), but good old fashioned wall switches couldn't hurt. I can't really see any safety concerns, but any thoughts or ideas are welcome! Thanks guys!
Grand Curtain Motorization
- Thread starterDenny586
- Start date
Les
Well-Known Member
There, fixed it for ya
There are kits to motorize curtains, but they aren't cheap. The biggest thing you would have to worry about with motorizing a grand drape is setting up reliable limit switches and gearing the motor appropriately. It's unlikely that a motor fed straight to the drape lines would give you the appropriate torque and speed control for a smoothly operated drape (or a happy motor). You'd also likely burn up the rope lines due to the sudden motor start-up, and likely mis-matched drums.
You'd also want a way to control the drum's tension on said pull lines.
I find that when I am on curtain duty, I use different speeds depending on the act, and usually I will vary the speed during the actual operation (slowing it down right before it closes to reduce the "snap" of it coming to an abrupt stop is a good example; same for when it opens). You mentioned your hesitation, but for DMX control, you would not want to use "intensity" to control the motor. (50% from a dimmer won't translate to half-speed for a motor, if it translates at all). You'd really want the DMX signal to directly feed some type of motor control device, which will take the DMX values and turn them in to readable instructions for the motor circuit. A simple on/off wall switch doesn't sound like it would work -- you'd get one speed (full blast), and I'm not sure how you'd reverse it. Sounds like a cool experiment (as long as it is your drape, your motor, etc), but make sure that the system can be overridden.
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Sounds like a TMFT issue (Too Much Free Time). I would leave it alone. My high school had a motorized curtain and it was always a problem. There's nothing like trying to re-wrap the rope on the drum correctly during intermission. Now it's hooked into the fire alarm system to close whenever the alarm goes off. The curtain knocks over any chairs and mic stands that happen to be in line with the curtain during fire drills. It's just unnecessary.
If you have free time, organize the gels and straighten out the prop room. They're always a mess.
But I already did that!! ahaIf you have free time, organize the gels and straighten out the prop room. They're always a mess.
I've got to jump on this bandwagon as well. There short answer is " There is not a cheap way to do this." When you add motor control into the equation your costs start in the low thousands and go up exponentially from there. Variable Speed? another couple K. DMX control another couple K. Training on how to program and run the equipment, Another couple K...... See a pattern ? Yes, You could go out and build yourself a speciallized custom captstian, hook it to a gear motor from Grainger, install limit switches, load sensors and up-grade all the sheavs pulleys and cordage on your Grand Drape system. Then you'd need to purchase or build a DMX - PWM control module and write the apropriate software. Assuming this is going into a school you'd then need to apply for and recieve a UL listing, and while you're at it you should probably file the apropriate Pattent papers....... All in all a PITA.
I'm not trying to discourage you at all, just doing a reality check.
I'm not trying to discourage you at all, just doing a reality check.
Just because you can doesn't mean you should. Some clueless individual did this at my school. The drive is professionally constructed, but they ran the controls to the control booth with 12/3 MC. There are three buttons, so they used the green wire as the common. (violation of 200.6) There's sharpie on it, presumably their attempt to recode it. 
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.Our newest high school's venue has a motorized curtain and it's just terrible. The speed they chose is too slow for the scenes you want a fast close on, and too fast for scenes you want a slower close. It's also built into the AMX building management system, meaning anyone with one of the tablets can open and close the curtain and there's no lockout. The actual buttons on a wall plate seem to have a mind of their own and the limit switches are horribly off.
Like the others have said, I'm not saying you can't or shouldn't do it. If you do decide to install a motorized system, it won't be cheap and getting it right can be very difficult and time consuming.
Like the others have said, I'm not saying you can't or shouldn't do it. If you do decide to install a motorized system, it won't be cheap and getting it right can be very difficult and time consuming.
Morte615
Active Member
Just saw this recently on the PLSN Facebook page so thought I would share
PLSN | Creative Conners Curtain Call
PLSN | Creative Conners Curtain Call
Just saw this recently on the PLSN Facebook page so thought I would share
PLSN | Creative Conners Curtain Call
You have to ask yourself: "Do I really need to spend $10,000 on a gizmo to open and close a curtain?"
I don't think it's worth the cost. Even if you pay enough to get a full range of speeds, good-quality hardware, natural-looking motion, etc, you'll have paid too much for what you actually got. And any sort of half-assed job will only cause trouble down the road. As I discovered, minutes before showtime, when it became known that the open and close controls of our motorized Austrian curtain are not mutually exclusive.
Outside of buying a $5k fixed speed motor or $12k ish variable speed motor package, I'd say you have two options and you should restrict both to paper until you have someone with the experience to help you. Paper may sound boring, but it's time well spent.
You either have to build a DC drive and use a DC motor so you can adjust speed by changing voltage. This is an older method but relatively simplistic. Look at how the drive system on a golf cart works.
To really step it up, you need a vector drive. These nifty little gizmos can do all sorts of really cool stuff with power. (change voltage, change phasing, change frequency) They can control an AC motor's speed by adjusting the output frequency, thus speeding up or slowing down the motor while maintaining full torque. An encoder on the motor shaft can feed rotation data back to the drive so it knows how many rotations/degrees the motor has turned. A little math and you know exactly where you curtain is. It's takes some programming and a whole lot of manual reading, but it's really cool. The possibilities are limitless. And thus, the wonderful world of automation....
The only thing that approaches the impressiveness of these gadgets capabilities is the nastiness of the electrical hazard. Worth spending your time reading about them, but find a good school or tutor before hooking one up. Arc flash, fire, or sudden death can be the toll for misunderstanding.
You either have to build a DC drive and use a DC motor so you can adjust speed by changing voltage. This is an older method but relatively simplistic. Look at how the drive system on a golf cart works.
To really step it up, you need a vector drive. These nifty little gizmos can do all sorts of really cool stuff with power. (change voltage, change phasing, change frequency) They can control an AC motor's speed by adjusting the output frequency, thus speeding up or slowing down the motor while maintaining full torque. An encoder on the motor shaft can feed rotation data back to the drive so it knows how many rotations/degrees the motor has turned. A little math and you know exactly where you curtain is. It's takes some programming and a whole lot of manual reading, but it's really cool. The possibilities are limitless. And thus, the wonderful world of automation....
The only thing that approaches the impressiveness of these gadgets capabilities is the nastiness of the electrical hazard. Worth spending your time reading about them, but find a good school or tutor before hooking one up. Arc flash, fire, or sudden death can be the toll for misunderstanding.
iandonahue
Member
There's no question that $10,000 is a lot for automating a curtain, but there are a number of situations where the money is well worth it. The biggest advantage is to couple your motor with computer control, allowing exact positioning, cue linking and coordination of multiple motors.
One example would be where you are handling hard scenery on a track and need the piece to finish its movement at an exact time, maybe aligning perfectly with another piece, and maybe that second piece is moving also. So you can see that granular control of speed, acceleration and target start to become features that you're willing to pay a little more for.
Another reason to spend that much money would be to save on labor. If you're already running automation for your show, your automation tech can handle the curtain moves instead of another stagehand, just like automating line sets.
Ian Donahue
Creative Conners, Inc.
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