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Author Topic: Interlocking strong and monee Peter John Anthony. C Film Handler Posts: 55 From: India Registered: Jun 2004 posted 11-24-2004 04:21 AM                     Hi! We are having a 4screens Plex, where screen1 has Strong projector & Screen2,3 & 4 has Monee projectors. I would like to use one print & show movie on Screen 1 & 2 (Strong has Synchronize motor & Monee has Inductance motor.) I would like to take your suggestion before going ahead. Thanks in advance. regards, Peter  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 11-24-2004 08:10 AM                        It's unlikely that projectors with inductance motors will run at exactly the same speed. Even a 1 percent speed difference is a significant difference in the length of film over a two hour feature. (Even more so with very long Indian "Bollywood" movies )  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 11-24-2004 08:56 AM                        108 feet in the case of a 2 hour 35mm feature (120 minutes = 10,800 feet at 24fps). That would need a very long loop absorber between the two machines to be able to start with that much slack if the second machine is running faster or to absorb the extra footage if the first machine is running faster. Selsyn motors are a must, I'd have thought.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 11-24-2004 08:58 AM                     Replace the induction motor, and the rive pulleys and belts with a sync motor and correct timing belt and pulleys  |  IP: Logged Peter John Anthony. C Film Handler Posts: 55 From: India Registered: Jun 2004 posted 11-24-2004 09:44 AM                     Thanks Gordon,if you have any details specs for pulley, sync motor & belt to easy my experiments please let me know. Thanks once again.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 11-24-2004 09:48 AM                     I would contact monee or there local rep to get the correct pulleys for to match the gear train of your machines also ensure that the motor is the correct line frequency and voltage for you location  |  IP: Logged Peter John Anthony. C Film Handler Posts: 55 From: India Registered: Jun 2004 posted 11-24-2004 10:02 AM                     Do we need to install Ups to give a steady supply to the projector motor. At present we are not using any & every thing is fine? Thanks once again.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 11-24-2004 10:12 AM                    That should not be necessary if the power is good enough to run what you have now. Motors are not bothered by the sort of voltage spikes and electrical "noise" that might cause problems with delicate electronics. Slight variations in frequency will cause slight variations in motor speed but this will affect all the motors in an interlock arrangement so everything will remain in step. You need an accumulator between projectors to give out slack film or absorb it only as the machines come up to speed as they may differ slightly. Once the synchronous motors are at speed they lock to the power line frequency and from that point on the slack between projectors will not change.  |  IP: Logged Peter John Anthony. C Film Handler Posts: 55 From: India Registered: Jun 2004 posted 11-24-2004 11:15 AM                     Steve one of my friends told me that some of his friend has done interlocking between three projector (Monee, Strong & Monee), they had a problem. With Monee & Strong no prob, Monee & Monee no prob, but sometimes Monee, Strong & Monee the film moving between Monee to Strong dangles down towards floor & film moving from Strong to Monee moves upward & gets tight or vice-verse. Due to which they have to stop the show & leave about 3 to 6ft of film loop between the two projector & run the show. This happens twice or thrice a week when they did not have ups installed. But after installing ups worth 543$ they had no such problems. Please advice. Thanks.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 11-24-2004 04:56 PM                        The UPS may just have changed the voltage somewhat, which could affect the speed of the induction motor. Syncronous motors "lock" to the line frequency when up to speed.  |  IP: Logged Peter John Anthony. C Film Handler Posts: 55 From: India Registered: Jun 2004 posted 11-25-2004 07:41 AM                     Yes John I completely agree with you. But these guys have installed the UPS for Strong Synchronize motor which confuses me & they say after installing the UPS everything works fine. Anyways thanks to all, for your kind advice. I will go ahead to interlock between Monee & Strong without UPS & if I face any problem I will get back for your advice. Thanks once again. Cheers.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 11-25-2004 11:11 AM                        Maybe the UPS output was slightly off line frequency?  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 11-25-2004 01:22 PM                    If it's the type of DC-linked UPS is that is working at all times (rectifier->inverter) as opposed to just a backup supply that kicks in when mains power fails then there could be problems unless one UPS can run all motors. I'd stick with utility power for all so if there is variation they will vary together.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-25-2004 01:46 PM                     We have several customers that run interlock without sync motors. These folks all have two loop accumulators and when things start to creep up they slow down the faster projector to put the trombone back in the middle with their hand in very heavy leather glove..... by slight friction on the flywheel. Dangerous.... a bit... but it works and is cheap. They claim they generally have to do this once in a 2 hour film and sometimes not at all. Using two loop accumulators gives one quite a bit of leeway between projectors. A DC invertor generating AC will not guarantee you perffect speed as induction motors inherently have alot of slip. Mark  |  IP: Logged Rick Long Jr Expert Film Handler Posts: 211 From: Toronto, Canada Registered: Jul 2000 posted 11-25-2004 03:18 PM                     There used to be a theatre here that ran interlock on a couple of Prevosts without sync motors. They had a large six-foot loop accumulator with micro-switches positioned near the top and bottom that would throw a resistor in series with the projector motor. Didn't work very well though. One machine was always slightly faster than the other, and as a result, the accumulator would ride up and toggle the switch on and off throughout the show, causing sound instability issues.  |  IP: Logged

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