# Turntable stage



## edwardanoland (Dec 3, 2008)

I'm new to the forum, of course. I'm trying to construct a 20' revolve for a high school play. I've downloaded the file from "Van" and found it useful. Has anyone built one that is economical and electric powered? Thanks!

Ed


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## Footer (Dec 4, 2008)

http://www.controlbooth.com/forums/scenery/8950-rotating-set.html

Flat out, automation will cost you money, and a lot of it. Building the revolve is not that huge of a thing, but doing the automation is.


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## cdub260 (Dec 4, 2008)

Footer said:


> http://www.controlbooth.com/forums/scenery/8950-rotating-set.html
> 
> Flat out, automation will cost you money, and a lot of it. Building the revolve is not that huge of a thing, but doing the automation is.



More to the point, doing the automation safely can be expensive. At the Pageant, we make extensive use of motorized turntables. We have two permanently installed, one of which is roughly 20 ft. in diameter. It uses two trailer tires driven by two very beefy AC motors with some serious gear reduction. It was built for us by Gala Systems about 25 years ago. It went through its most recent system upgrade 2 years ago. That upgrade alone ran us several thousand dollars.

We have several other portable turntables which are designed to be installed on rolling scenery so that we can have rotating sets for some of our statues. These consist of 1/2 horse power, 90 volt, DC motors and a chain and sprocket assembly attached to a steel frame. This set-up can handle up to a 12 ft. diameter set without any problems. I can't give you any figures on costs for these systems, as they were all built prior to 2000, which is when I joined the Pageant staff. However, I can tell you that the controller for these turntables runs about $700.00.

On an annual basis, I give each of these systems a thorough inspection to ensure that they are operating within specs. With any type of electrical or motorized system, there is the very real possibility that if there is a problem, someone could get hurt or killed. For that reason, you cannot take shortcuts to trim your budget. It has to be built so that it's safe. When dealing with motorized systems, that costs money.

Check out the thread that Footer highlighted. It should give you some insight into what is involved with building motorized turntables.


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## icewolf08 (Dec 4, 2008)

Ass everyone has said, the revolve itself isn't the expensive part, the motor and control system is.

I'll put a quick plug in for my buddies over at Creative Conners Inc. Their philosophy is to create automation systems that are accessible to all types of users. They will happily consult with you on a system, and you can rent the gear from them if you don't want to buy it. It is easy to use and cue, and it is designed to be a very safe system.


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## TheDonkey (Dec 4, 2008)

icewolf08 said:


> Ass everyone has said, the revolve itself isn't the expensive part, the motor and control system is.
> 
> I'll put a quick plug in for my buddies over at Creative Conners Inc. Their philosophy is to create automation systems that are accessible to all types of users. They will happily consult with you on a system, and you can rent the gear from them if you don't want to buy it. It is easy to use and cue, and it is designed to be a very safe system.




Just out of curiosity, assuming that the Controller is under the actual table surface and it's all structural, how tall does the whole thing stand?
And how is it controlled? TurnPot cabled to the controller or DMX or...? I assume there are multiple options?


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## Gretsch (Dec 4, 2008)

Is there a specific reason you need it to be powered? The best way I have seen to make turntables or revolves is to build the main body out of 4'x8' platforms with rounded plugs to round it out. If you put all idiot casters on there at the right angle it will always run in a circle or with a fixed center pivot you can use all smart casters and get the same result. There are a variety of ways to rotate it but good old grip power is the most reliable for the least cost.


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## maccalder (Dec 4, 2008)

TheDonkey said:


> And how is it controlled? TurnPot cabled to the controller or DMX or...?



Just a quick note:

DMX contains no error checking at all, and should never be used for safety critical applications - including but not limited to moving scenery, revolves, pyrotechnics etc etc etc. To quote the USITT website:


> Error Correction - Can I use DMX512 for control in hazardous applications?
> No. DMX512 does not have any inherent error detection. In fact, the ANSI version added language stating: "There is no assurance that all DMX512 packets will be delivered" and "Since this Standard does not mandate error checking, DMX512 is not an appropriate control protocol for hazardous applications." Even with the data packet being refreshed constantly, there is no method for the receiver to determine that the information it received is information the transmitter (console) sent. One bad data packet, even if corrected in the next packet, can cause something to move or energize when it shouldn't. DMX512–A does offer a standard method for sending a checksum which can be part of an error correction routine (Annex Clause D4), but this is an optional implementation and cannot be relied on.



and 


> DMX512 and DMX512, with it's lack of error detection, is NOT appropriate for some applications - such as pyrotechnic control and scenery automation


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## Footer (Dec 4, 2008)

TheDonkey said:


> Just out of curiosity, assuming that the Controller is under the actual table surface and it's all structural, how tall does the whole thing stand?
> And how is it controlled? TurnPot cabled to the controller or DMX or...? I assume there are multiple options?



Automation+DMX=Dead people. 

There are a few ways to automate a revolve. The easiest way, is to run a ring round the revolve, and have a drive wheel parralel to the riing that makes the thing go. Flat spots almost always begin to appear around the ring. This is by far the worst way to run a revolve. 

After that, cable drives are becoming popular. They are easy to rig if you already have a cable drum winch in stock, which most theatres who do automation do. They work pretty well, but slipping can still be an issue. The best way to go if possible is a chain drive. To do this correctly, you need a fairly long chain, which can be very expensive. By doing this method though you have very good power transfer. 

For AC motor control you need a few different things. First things first, you need a motor. In the theatre world, usually it is built into a frame that attaches it to a cable drum. The motor hooks up to a Variable Frequency Drive (VFD). This thing is rated based on the horse power of the motor. It varies the frequency of the power being put out to speed up/slow down the motor. Beyond that, you now need a controller. The defacto standard for a number of years has been Goddard

AWU SERIES MOTION CONTROLLERS

If done right, you can also use a "hot box" which is basically a pot to control speed, and forward button, and a reverse button wired into the VFD. If the proper safety measures in place, and you have a competent operator, this is a way to go. 

Motor control is now moving towards PC based systemsl. Creative Conners offers a system to easily tie in your old winches used with a goddard to their control system. Beyond the cue driven controls, you also have to incorporate a series of safety features such as limit switches and dead man switches. 

Controlling automation is expensive, and takes time. People go to grad school and just to do/learn automation, its not something that can be just thrown together. However, with ever increasing labor costs, many theatres are now looking to automation to cut down on overall show costs. I know of one theatre that invested in 5 winches, 5 goddards, and a heap of other stuff a few years back, and has the blanket marching orders to all designers that they get one crew member to operate their show, and that guy is pushing a go button. That also makes the TD do more work, but overall it saves the theatre money and raises the production value.


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