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Author Topic: Reversing the Direction in a Projector Al Chaney Film Handler Posts: 33 From: Madison, AL Registered: Mar 2001 posted 03-02-2003 02:42 PM                     How can I reverse the direction of the film in a projector. I have a ac motor on my projector.How can I get it to stop ant then reverse the direction. If I just switch the wires will that work or will I need a special motor or wiring diagram? Al  |  IP: Logged Mike Rendall Film Handler Posts: 78 From: Southampton, Hampshire, UK Registered: Nov 2002 posted 03-02-2003 03:09 PM                     If you don't have an intermittant at the top of the gate then I don't think you can run the machine backwards without making a terrible mess. I.e. it will snap (or if poly - something worse) when the loops get chewed up. -however- If the motor is 3-phase then swapping two phases over will make it run backwards. If it is single phase then just swapping the wires around should have the same effect.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-02-2003 03:46 PM                     Al, You also have to be careful as many intermittents are not designed to be run in reverse. The oil spirals that are ground into the shafts of many Star Wheel's will end up taking the oil off of the shaft instead of taking clean oil down the shaft. One has to fit oilite bushings to these areas to be sure that they are constantly lubricated. The Christie P35 movements are an exception to this as the oil spirals are machined into the internal bushings, not the shafts themselves, and the outer bearings are ball bearings instead of bushings. Hence, the Christie projector would be a good candidate to run in reverse with out having to worry about this. You also do have to relieve the gate pressure, or fit auxilary guides to keep the film going back up through the trap. Otherwise the film will pop out, usually where it enters the trap. The ballantyne projector can also run reverse and the special gate parts are available off the shelf for converting those over. The movement in that machine is ok to run reverse as its completely submerged in oil. Mark @ CLACO  |  IP: Logged Rick Long Jr Expert Film Handler Posts: 211 From: Toronto, Canada Registered: Jul 2000 posted 03-02-2003 10:22 PM                     Can't help but want to ask why?????? I've seen some 2 machine setups that rewind the reel through the machine (Cinemeccanica Vic-8) The trap would open slightly, and it had a different intermittent shoe design as well as a couple of rollers to keep the loops in place. But it was not intended to project in reverse.Simplex could rewind on the machine, but not through it. The only machine I've seen that can project while going backwards is a Magnatech electronic projector. But even its trap opens slightly, and as a result will not give a truly steady image. Film transport is also a concern, as I know of no platter able to go backwards. The reel to reel setups had a belt to drive the upper reel.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-02-2003 10:38 PM                     Rick, Check out the Kinoton E series projectors...the E-R, E-S and EC projectors all can project in reverse in addition to shuttling in reverse. As to why...imagine an automated changeover booth where after changeover...the outgoing projector rewinds (shuttles). For film evaluation, then one would want to project in either direction. We have a film processing lab that specifically wanted forward/reverse operation and variable speed control (down to 1fps). The controls are remotable so they can evaluate the film right down at the screen frame-by-frame if need be. It all depends on your needs. Steve  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-02-2003 10:43 PM                        What wattage lamp can they use while projecting at 1 fps?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-02-2003 10:57 PM                     What wattage lamp would you like to use? Since this is a lab they are only effectively running at 700 watts but you could go up into the thousands. Remember, for Kinoton E series...the shutter is spinning continiously and below 20fps, it acts like a 3-wing shutter and at 10fps, a light reducing douser drops into the light path to cut down on the radiant energy. Steve  |  IP: Logged Joe Morris Film Handler Posts: 35 From: Papillion, NE, USA Registered: Jan 2003 posted 03-02-2003 11:07 PM                     some of the old century projectors that had the straight gates were able to run backwards if you rewire the motor correctly. It just depended on the film gate you had in your projector.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 03-02-2003 11:19 PM                    I have straight reversing gates & traps on my Simplexes (they predate the machines they're on and were not put on for reverse use). They have an adjustment to take the trap rails as close as possible to the intermittent. I don't run reverse and am not set up to do so in terms of takeup and hold back and not sure what the lubrication issues would be but I do know it's possible to crank it backwards by hand (like if I overshoot where I want to cue to) and film moves smoothly through the gate in reverse with no tension relief needed.  |  IP: Logged Philippe Laude Film Handler Posts: 79 From: Longueville, Belgium Registered: Jul 99 posted 03-03-2003 01:58 AM                     The studio projector Bauer B14 can also project backwards. Philippe Laude  |  IP: Logged Bernard Tonks Jedi Master Film Handler Posts: 619 From: Cranleigh, Surrey, England Registered: Apr 2001 posted 03-03-2003 06:31 AM                     During my television days at ITN News before changing to complete video & ENG, Philips (Kinoton) FP20 projectors were used for 35mm R & R in the dubbing theatres, and in Telecine. There was never a problem running in reverse with the gate kept closed.  |  IP: Logged Duncan Smith Film Handler Posts: 50 From: England Registered: Jan 2003 posted 03-03-2003 07:15 AM                     It might be drifting off the original point a bit but I've seen a pair of Sondor 35mm projectors at a friends preview theatre in London and they can do almost anything it seems. Up to 250fps off screen and 50fps on screen I think, through the gate too! I've also seen it run at less than 1fps for framing and focus etc. When he's mostly running adverts etc he never seven uses the rewinder as it'll rewind about 3 minutes of film in a few seconds, very well too I might ad. It's probably the most advanced projector I've ever seen, fully electronic. I'm quite envious!  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 03-03-2003 08:45 AM                        Talking about speed control (well kind of), does anyone have any recommendations as to an particular manufacturer of projector speed control units? I've only seen one in actually operation --it was the feedback type that read pulses off the drive shaft and a control box displayed the fps. I believe you could lock it at 24fps and perhaps a few other speeds (18fps probably) but you could also put it in manual and dial up any speed you needed via a pot on the control unit. Not sure of the speed range, but I know it was substantial. I am not sure if the motor has to be swapped out with a stepping motor; I'm guessing the standard induction motor probably couldn't work with this kind of controller. Anyone use this type of control unit? We were thinking of putting it in for silent film on a Century JJ but then realized that we could get 18fps just by using a different sized pully and belt, which was a cheaper but not nearly as elegant a solution as one of these electronic controllers. Frank  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 03-03-2003 09:24 AM                        Eprad had such a setup, though I only saw a couple of them and heard they weren't all that reliable overall. It ran in conjunction with their Sword film transport system (the reels would work backwards as easily as forwards, and were "tried" in a few theatres in the Seattle area. These places got to where they really tried to run with one person, and you saw a lot of Eprad remote boxes on the walls behind the cash registers. The couple systems I saw had Century SA heads, reversing motors & an ugly looking solenoid that pulled the trap shoes back. The system was a two-projector arrangement, and the automation was set up to kick the outgoing machine into reverse once it had changed over to the other machine (or shut down at the end of the show). Seems an awful way to handle film, considering that, gate tention and oiling issues notwithstanding, you're putting double the mileage on everything, & the whole point is not to have to be in the booth while this risky operation is running.  |  IP: Logged Joe Beres Jedi Master Film Handler Posts: 606 From: Minneapolis, MN, USA Registered: Nov 2000 posted 03-03-2003 09:36 AM                     Frank, I had T.B. Woods motor control units on the pair of Ballantyne Pro 35s I used to run. They were purchased from International Cinema Equipment. They could be programmed for any speed, and the speed was displayed in fps. The ramp-up/down speed was also programmable. It's a nice and versatile unit.  |  IP: Logged

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