brainwave-generator Posted June 30, 2012 Share Posted June 30, 2012 Whilst industrial motors are commonly 3-phase, single phase motors are readily available for buildings which do not have a three phase supply. A three phase motor, likely powered through an inverter for speed control, would be the right thing here due to the relative ease of reversing the direction via a L2/L3 phase swap. Single phase motors require more complicated control gear to run CW and CCW. True, but my point was simply to point out that it's not a case of "if you don't have a 3-phase supply you can't use electric motors" as the previous poster said, because you can use single phase motors. Link to comment Share on other sites More sharing options...
bigclive Posted June 30, 2012 Share Posted June 30, 2012 Yes. A capacitor. Although you could also use a variable frequency drive that took a single phase supply and used it to drive a three phase motor. While we're all about piling in extra features, how about programmable stop positions. Then you could have an LCD touch screen with pretty graphics too. Link to comment Share on other sites More sharing options...
Giles Favell Posted July 1, 2012 Share Posted July 1, 2012 At this size, powered is the only sensible professional option - and I would also leave it to the professionals.Either Charles Haines at Hall Stage, or Davis Edelstein at TripleE. Both are consummate professionals, who know exactly what they're talking about, and for whom this is their daily bread and butter.They both have the right products and can give the right guidance to give the optimism results. Link to comment Share on other sites More sharing options...
Jivemaster Posted July 1, 2012 Share Posted July 1, 2012 Installing a curtain that will weigh about a ton will need significant professional input! Moving it safely and at an appropriate speed for the production will need some serious control, programmable stop points and motor soft starts seem like good items to have. Link to comment Share on other sites More sharing options...
paulears Posted July 1, 2012 Share Posted July 1, 2012 This is an interesting topic, and has swung from virtually everyone behind manual, through to everyone behind powered. I'd bet the OP hadn't even thought that getting a curtain opened would be of sufficient interest and depth to generate all this. A school near me have a big drama hall with a perimeter curtain track (T60, I think) and it follows the outline of the room, meaning lots of 90 degree bends as the room is a very odd shape. I saw it new a few years ago, but now it's ripped, bent and a real mess. Link to comment Share on other sites More sharing options...
Junior8 Posted July 1, 2012 Share Posted July 1, 2012 This is an interesting topic, and has swung from virtually everyone behind manual, through to everyone behind powered. I'd bet the OP hadn't even thought that getting a curtain opened would be of sufficient interest and depth to generate all this. A school near me have a big drama hall with a perimeter curtain track (T60, I think) and it follows the outline of the room, meaning lots of 90 degree bends as the room is a very odd shape. I saw it new a few years ago, but now it's ripped, bent and a real mess. This a very good point and reminds me of many discussions with architects over a project in 1990 when they simply did not - and would not make any effort to - understand that school buildings suffer different wear and tear to the normal projects they were concerned with. (Contract cleaners made the same errors when tendering too.) I could match Paul's experience and not just with perimeter drapes either. Education authorities used to have more sense too.. Link to comment Share on other sites More sharing options...
bigclive Posted July 1, 2012 Share Posted July 1, 2012 The best thing about such a large automated curtain is the winch will be so strong and the tension on the ropes so high that when something does go wrong it will be both very exciting and involve lots of shredded fabric. All at the touch of a little button. Link to comment Share on other sites More sharing options...
Brian Posted July 1, 2012 Share Posted July 1, 2012 ...lots of shredded fabric. All at the touch of a little button.Or, accompanied by the spectacular sound of ply 'tearing', the ruination of a very big, very shiny, very expensive piece of set complete with the inbuilt, wireless controlled, LED lighting. Whoops. Link to comment Share on other sites More sharing options...
Jivemaster Posted July 1, 2012 Share Posted July 1, 2012 My guestimate is that the curtain will be not much under one ton (or tonne!) and I'll challenge most individuals to move a car by pushing it 10 metres in one second under control. If anyone has a better estimate of the weight of the curtain and the realistic pull on cable required to move the curtain please post it here! Link to comment Share on other sites More sharing options...
paulears Posted July 1, 2012 Share Posted July 1, 2012 Not just schools - accidents happen for all sorts of reasons. http://www.youtube.com/watch?v=rrjYC3gTzQE I made this short video clip un-private. I made this to explain to the powers that be exactly what had happened during the panto. When the house tabs (big, heavy, velvet,expensive and good condition) were flown out, and the hem caught on the false pros! Oops. Link to comment Share on other sites More sharing options...
howartp Posted July 1, 2012 Author Share Posted July 1, 2012 This is an interesting topic, and has swung from virtually everyone behind manual, through to everyone behind powered. I'd bet the OP hadn't even thought that getting a curtain opened would be of sufficient interest and depth to generate all this. A school near me have a big drama hall with a perimeter curtain track (T60, I think) and it follows the outline of the room, meaning lots of 90 degree bends as the room is a very odd shape. I saw it new a few years ago, but now it's ripped, bent and a real mess.Paul, You've hit the nail right on the head there - after the first few responses, up to and including your first one, I PDF'd this thread and handed it to the project manager and our head teacher with words along the lines of 'this is the response from the tech community from West End Theatres to touring stage teams etc - the only surprise is that paulears (whom I hold in high regard) has suggested electric'. If I may qualify this, of the half-dozen threads on BR that I've created, I think you Paul have responded to all of them with good useful information, and the PDF was before you responded again. So I think I'm going to re-PDF this entire thread and take it to a meeting on Tuesday, after I've had a (already-booked) phone converation with the company doing the theatre install. Peter Link to comment Share on other sites More sharing options...
Nicktaylor Posted July 2, 2012 Share Posted July 2, 2012 21m is a huge amount of curtain to shift though - fast hauling a 12m curtain is tough on the muscles, this one has 50m of hauling rope - so friction is going to be quite high, isn't it? For this length, they'll probably use wire rather than rope hauling on a slotted fixed drum, I'd have thought, rather than just hanging onto a rope. 21m also suggests that the actual hauling speed will need to be very fast - to open the gap in a realistic time. Yes, even our existing hall uses a steel rope winch on what sounds like it is the same as a slotted fixed drum - I wasn't sure how to describe it but that sounds right - so I would think they will do the same in the new hall.http://www.sprucedesign.com/images/uploads/Winch-Manual-Wall-.gifPeterOne local venue has added a larger disk under the handle. This stops the wire being thrown off if an operator is too over the top winding Link to comment Share on other sites More sharing options...
paulears Posted July 2, 2012 Share Posted July 2, 2012 These drum style winders in a school environment, or even a self-op amateur environment worry me, and always have done. When even using them responsibly, it's very easy to get long hair trapped, or perhaps even lanyards with ID cards dangling. If the need is for speed, then it's the attempt to keep up a consistent high rate of knots that can get them out of hand. I suppose a sheet or mesh cover could be fabricated improving safety, but I've not seen one yet? Link to comment Share on other sites More sharing options...
T*ny Posted July 2, 2012 Share Posted July 2, 2012 21m x 7m = 147m2 - call it 150Wool serge is around 500g/m2 which gives us 75kg.Allow for 50% fullness gives a weight of 112.5kg. Even allowing for lining it is nowhere near a ton(ne) but I still wouldn't like to try opening it in a hurry by hand Link to comment Share on other sites More sharing options...
kerry davies Posted July 2, 2012 Share Posted July 2, 2012 Interesting thread, as more information such as scale has come to light the argument has swung one way then the other. It supports my thoughts that posing the question accurately and comprehensively is more important than a choice of answers. Something the OP posted early on has had me thinking, ...there was encouragment from others on the team to go electric... I immediately remembered an instance when a new technique was being introduced and the one who operated it was the single person against it. It was introduced and immediately went pear-shaped and I learned a vauable lesson. If those asked to perform a task do not have faith in it, it invariably goes wrong. Call it sub-conscious sabotage or just Murphy's Law, but what attitude others bring can be more important than almost anything. FWIW, electric motors don't have "attitude", generally speaking! Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.