30' Revolve

[simchapup]

we are trying to do a 30' Revolve for our fall show at my university. I am starting to work on automation for this show. We want to use an existing motor we have to drive our revolve. we have been using the mechanical design for the stage book but we are having trouble figuring out horsepower and torque needed to turn it. We would like to to do a direct drive if at all possible if not we are looking for a way to use chain as to prevent slipping and a way to attach facing. We plan on building with casters wheels up on the deck to support the revolve and to level our casters on an non level stage. Our specs are as follows

Winsmith 924 speed Reducer
1750 RPM
960 Torque in.-lbs.
The HP says 2.08??? not sure if this is correct

We need to do a 120 degree turn only one way but if possible 360. We are estimating having about 4000 lbs for the revolve (structure, set, and actors).
Any advice would be very helpful.

 

[skienblack]

I am going to assume this is a 30' diameter? How fast do you need this to rotate 120 degrees? After you answer these questions you can be better advised on your options.

 

[simchapup]

I am going to assume this is a 30' diameter? How fast do you need this to rotate 120 degrees? After you answer these questions you can be better advised on your options.

Yes 30' diameter and we need to be able to rotate in about 10-30 sec.

 

[skienblack]

Ok. So your looking at a circumference of ~93'. Thus 1/3 of that would be 31'. So in order to rotate 120 degrees in 30 seconds, which is your minimum, your looking at the this revolve traveling at 60' a minute which is fast to have scenery and people on. I would rethink this first.

As for your gearing and motor. Assuming you have a 2" gear on your motor you will be moving 6.25" every rotation. And your stage has a circumference of 1116". So with your 1750 rpm you could rotate the stage ~10 times per minute. But now we have to calculate the torque required to move it. I will come back to that later. Got to go to work!

 

[simchapup]

Ok. So your looking at a circumference of ~93'. Thus 1/3 of that would be 31'. So in order to rotate 120 degrees in 30 seconds, which is your minimum, your looking at the this revolve traveling at 60' a minute which is fast to have scenery and people on. I would rethink this first.

As for your gearing and motor. Assuming you have a 2" gear on your motor you will be moving 6.25" every rotation. And your stage has a circumference of 1116". So with your 1750 rpm you could rotate the stage ~10 times per minute. But now we have to calculate the torque required to move it. I will come back to that later. Got to go to work!

Awesome thanks for the information.

30 seconds was an estimate what do you think would be a better number? do you think a minute would be better?

and torque was a major problem for me to figure out if you can break down the steps to get the answer that would be awesome.

Thanks

 

[Van]

I'm much more concerned about the torque issue myself. I haven't done the math yet but 972 in#'s is not very much. With a center mount rotation system you get no mechanical advantage like you do with a wheel driven, or chain driven system.

All the mathmatics aside...I'm assuming you will have installed all appropriate safety systems such as limiters and dead-man switches? Most especially if you have actors on the unit while it's spinning.

BTW 30' is a huge diameter revolve.

 

[simchapup]

I'm much more concerned about the torque issue myself. I haven't done the math yet but 972 in#'s is not very much. With a center mount rotation system you get no mechanical advantage like you do with a wheel driven, or chain driven system.

All the mathmatics aside...I'm assuming you will have installed all appropriate safety systems such as limiters and dead-man switches? Most especially if you have actors on the unit while it's spinning.

BTW 30' is a huge diameter revolve.

we have not yet made our system but dead man switch and e stop plus safety checks are all in mind. yes 30' is a huge diameter our proscenium opening is over 50' wide. torque was also my main concern. This is our university's first time to really automate. we have 3 deck winches and lots of pneumatics that have just been sitting around and collecting dust unfortunately so for this show since were in a good stage to plan we really want to start automation.