draco17315
Member
Hello all, and thanks for any help.......ok, here's the scoop. We are building a revolve for use in two shows, Annie and Les Mis...I know...using a motor is rough, but we have the equipment and all that, we have the safety under control, we have an engineering student helping as well.....here is what we need help with, a little info first, it is a 22' diameter, we have used the 'cheese' method that so many people have recomended, we built it on a strong, steel pivot point that is lubed up and the casters are at all the preassure points, upside down attached to "arms" that radiate out from the central pivot point. They are rigid casters and are on the correct angles. manually, the stage seems to spin fine. we then ran a (sorry forget the name) schedule 40 chain (like a motorcycle chain) around the groove made by the wedges around the outside of the turntable then the chain exits through two tension gears that streighten out the chain that then runs back to the sprocket on the 3/4 HP motor we have. We have a nice speed control box, all that works fine except:
1) I think and from all the reading I found that the motor should be pulled back so that all the slack is out of the chain and then the motor should be mounted in a fashion as to not move. I dumb it down for myself like this.....remember when you were a kid and rode your bike everywhere.....it never failed, sometimes your chain would pop off...the solution...turn your bike upside down, loosen the wheel bolt, attach your chain to the fron and back sprocket on the bike, pull the tire back until the chain was tight and then tighten the bolt back down.....isnt this the same principle just on a much larger scale??? however my assistant who is an engineering student (and very smart.....) thinks we need to mount the motor to a "cart that rolls slightly forward and backwards and then use springs pulling back on the motor cart to keep the tension tight but allow the motor to still "adjust" itself as the turntable spins allowing the motor to "self correct" to compensate for any human error in cutting the turntable itself...would this really be necesarry????....we tried this to no avail, the chain kept popping off and the time that it did not pop off, the chain did not have enough friction to spin the turntable, it just rubbed arround and spun freely without spinning the turntable which brings me to problem #2.....
2) What can we do to get the chain to "grab" the turntable and get a constant rotation without the chain slipping?
3) we want to increase the safety with an e-stop....I am told mushroom e-stops are the best way to go...can anyone send me a schematic to add these into the wiring and where can I get them....also, does a common household light switch provide the same oporation as an e-stop or deadmans switch?
I think that is the most of the problems for now....I do best with diagrams, very visual, but any and all help is appreciated........thanks for all help
Joe
Technical Director
Susquehannock High School Theatre
Glen Rock, PA
1) I think and from all the reading I found that the motor should be pulled back so that all the slack is out of the chain and then the motor should be mounted in a fashion as to not move. I dumb it down for myself like this.....remember when you were a kid and rode your bike everywhere.....it never failed, sometimes your chain would pop off...the solution...turn your bike upside down, loosen the wheel bolt, attach your chain to the fron and back sprocket on the bike, pull the tire back until the chain was tight and then tighten the bolt back down.....isnt this the same principle just on a much larger scale??? however my assistant who is an engineering student (and very smart.....) thinks we need to mount the motor to a "cart that rolls slightly forward and backwards and then use springs pulling back on the motor cart to keep the tension tight but allow the motor to still "adjust" itself as the turntable spins allowing the motor to "self correct" to compensate for any human error in cutting the turntable itself...would this really be necesarry????....we tried this to no avail, the chain kept popping off and the time that it did not pop off, the chain did not have enough friction to spin the turntable, it just rubbed arround and spun freely without spinning the turntable which brings me to problem #2.....
2) What can we do to get the chain to "grab" the turntable and get a constant rotation without the chain slipping?
3) we want to increase the safety with an e-stop....I am told mushroom e-stops are the best way to go...can anyone send me a schematic to add these into the wiring and where can I get them....also, does a common household light switch provide the same oporation as an e-stop or deadmans switch?
I think that is the most of the problems for now....I do best with diagrams, very visual, but any and all help is appreciated........thanks for all help
Joe
Technical Director
Susquehannock High School Theatre
Glen Rock, PA