This is topic Two questions here in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=002965
Posted by Michael Wohlford (Member # 905) on 01-14-2002, 05:09 PM:
My first question: Does anyone have the keys to lock out the backs and lamphouses of the CFS LM2500 consoles? Email me if you have a key and can make a copy.Second: I saw this on a picture. It is some kind of failsafe sensor. It has 3 rollers in the shape of a triangle. When film tightens, like a brainwrap, the third roller (the point of the triangle) will move up or something and turn off the projector. What is this doo-wacky called?
Posted by Michael Wohlford (Member # 905) on 01-14-2002, 05:16 PM:
Sorry Brad about the topic name. I couldn't think of anything else to use. I couldn't help making it a "teaser" name.
Posted by Aaron Sisemore (Member # 145) on 01-14-2002, 08:50 PM:
Answers:1. All the keys are keyed alike, so someone might be able to get a key mailed to you. I suggest leaving things UNLOCKED, unless you have a problem with people monkeying with things they shouldn;t be. Trust me, when something goes awry, the lamphouse keys are the first things to go missing.... Murphy's Law.
2. The device is commonly called a Tension Failsafe or Tension Sensor. It will kick the automation into stop mode if feed tension is too great.
-Aaron
Posted by John Eickhof (Member # 323) on 01-14-2002, 08:54 PM:
Email your address, I will send you a key, it is a corbin key marked
wn-09 I have lots of them... Also, the tension safety switch I think you are referring to is made by Potts and marketed through Potts and Ballantyne/Strong, they work quite well.------------------
John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258
208-536-5489
email: jeickhof@nteequip.com
Posted by Pat Moore (Member # 380) on 01-14-2002, 09:15 PM:
Aaiiee!! John -- that Wrap Detector you describe is made by Design Manufacturing and Strong -- it was not originally a Potts product.See you at ShoWest this year?
Posted by Wes Hughes (Member # 981) on 01-15-2002, 02:01 AM:
The overtension failsafe you mention is a handy booth addition. They are well worth the price if you have a large and/or unmanned booth since one nasty brainwrap could cost quite a bit in lost revenue. I put them on ever platter stack at one of my theatres. They need not be wired into the automation console...just wire them into the variac on the platter so that if the detector trips it cuts power to the platters, and when the takeup goes slack the projector will fault out via it's exsisting failsafe.
...oh, and the lamphouse key??? Just get a flat head screwdriver and force the lock open...if that doesn't work pry the door open!!! The lock toggle will usually bend easily. I've done it a lot of times on christie lamphouses, poster frames, anything with those cheap-o short cylinder locks.
Posted by Steven Gorsky (Member # 603) on 01-15-2002, 02:44 AM:
I feel the failsafe would work best if it is wired to the automation, or if possible the variac and automation. For a few months I worked at two theatres (same mall) with the Strong booth package. My only complaint (besides a little oil 
) was the platter failsafe (at least the way it was connected). There were a couple of instances when the failsafe cut power to the platters, but the projector still kept pulling 
(CPA-10 automation and FP-350 projector failsafe). Worst part was when it happened near the end, no one would complain 
, and you wouldn't notice anything wrong (no alarm) if you were at the other end of the booth cleaning and threading other projectors.
I had planned on changing the wiring for the platter failsafe to the automation, but I left (poor pay, bad neighboorhood, etc.) before I did it.
Steven Gorsky
Posted by John Walsh (Member # 168) on 01-15-2002, 10:41 AM:
At our theaters, we prefer the platter-wrap sensors that have a sliding carriage to allow about 6-8 feet of film travel *after* the film has bound at the payout head. Many projectors with big flywheels (particularly Simplexes) will continue to pull film after the sensor switches are tripped. Those triangle shaped sensors (and others that only "look" for increased tension) may not prevent sprocket damage or guide rollers frrom being pulled out of position.We bought the ones made by Nuemade/Xetron, and have used them on most of our platters, even plattes not made by Nuemade/Xetron.
Posted by John Pytlak (Member # 331) on 01-15-2002, 03:51 PM:
Kodak has consistently recommended tension-sensing failsafes on platters for polyester film. I agree that the models that have some slack to let the projector coast to a stop without damaging film are the best option. IMHO, they should be wired directly into the automation, so the projector stops immediately, rather than having the platter take-up stop, and then another fail-safe detect that.------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
Posted by Leo Enticknap (Member # 534) on 01-15-2002, 03:55 PM:
IMHO, the ideal would be that when the wrap detector is activated, the system is wired so that power to the motors of both the projector and the platter are cut simultaneously. The second or two it takes a capacitor to discharge is enough to cause the sorts of problems that make the difference between two minutes to get your show back on the screen and ten.What I mean is, if for whatever reason the projector stops first and the platter take-up plate keeps pulling for a second or two, that can pull a guide roller out of alignment that would take precious minutes to find while the customers downstairs are giving you a slow hand clap!
Posted by Tom Fermanian (Member # 1094) on 01-15-2002, 07:34 PM:
We have fail-safe systems on our platters + Kelmar Film Choppers on each projector, whatever buggers up, my poor equipement won't !
Long live polyestar!!! 
------------------
Posted by Brad Miller (Member # 2) on 01-15-2002, 09:06 PM:
I am absolutely for any wrap detector that cuts power to the platter, whether it is wired into the automation or not. Of course having it wired into the automation is preferred, but if the wrap detector shuts down the system and a wrap has started, leaving power to the platter on can make a wrap problem WORSE if the payout is still spinning after the jam.As to the "choppers", what a stupid idea! The film gets mangled enough on a wrap. There is no need to put another splice in the film.
Posted by Tom Fermanian (Member # 1094) on 01-15-2002, 09:42 PM:
Don't like film choppers?
I would rather have a second protection in case fail safe on the platter doesn't kick in for some reason, I've seen bent shafts ,guide rollers, even a tipped over projector, I would rather in this case add an extra splice than risking damaging my equipement for polyestar film that many theatre operators and I did not ask for even if NATO did approve it!One quick tought, what film supplier will pay for any damage to projection equipement? They certainly charge us for damaged film 
------------------
Posted by Frank Angel (Member # 248) on 01-18-2002, 12:36 AM:
I've got the best failsafe -- change-overs with a real projectionist in the booth. 
Posted by Brad Miller (Member # 2) on 01-18-2002, 12:39 AM:
Yeah, but I'll bet you're not as fast shutting the projector down as a real failsafe if that takeup belt breaks!
Posted by Steve Guttag (Member # 268) on 01-18-2002, 12:21 PM:
Belts? You're still using belts? The film chopper has some merit though...the idea was that it would engage before the film stretched. Therefore, you have the one splice to make but no mangled film...kinda like making polyester break like acetate.
On some platters, killing the automation is preferred...for instance, if one has a Potts/Strong microswitch or phase control platter. If the projector stops, the take-up platter will stop and thus force the payout platter to stop (they reference the payout speed off of the take up speed).
Now for independant platters like Christie and the Strong SCDC, killing the platter is a good idea to prevent the run-away.
Steve
------------------
"Old projectionists never die, they just changeover!"