Film-Tech Forum ARCHIVE: Auto strike on motor start.

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Posted by Stephen Furley (Member # 1277) on 08-09-2002, 06:19 AM:

I have seen a few places, including one where I was running the show, where the xenons auto strike on the motor start, and go out on the motor stop. What is the point in this?

In some cases a lamp can take a few seconds to settle down, and is not at its best whin the picture hits the screen. I think there is usually a manual strike button which gets round this problem, but even worse is the problem of not being able to stop the motor, without putting the lamp out. This may not be such a problem with platters, but is a real pain if running changeovers with short reels, sometimes several films of just a few minutes each, or if running a sngle machine with adverts and trailers on a spool on the porjector, then main feature on a tower, something quite common at independents here in the uk. (you can run the adverts and trailers while the tower is rewinding the feature). Even if you are running on a platter, it means puting the lamp out for just a few minutes, while you rethread, and then re-striking.

The only possible advantage I can see to this is that it might slightly simplify an automation system, I don't know anything about them and have never run one, but I suppose that the lamp strike would be one less event to have to programme into the system, but this hardly seems like a major advantage.

What is the reason for this, especially in a changeover house? (single screen, built just a few years ago with brand new FP30Ds and Kinoton lamphouses).

Posted by Pete Naples (Member # 761) on 08-09-2002, 07:16 AM:

Probably because most automations use the zipper (change-over douser) to cut the light off, these don't like having the bulb running on the back of them for any length of time, so the lamp strikes up when the motor is running. Two things to that; the shutter will be turning so the heat and light on the zipper blade isn't so severe, and also it'll be a matter of seconds before the zipper opens anyway.

With decent automations you could program it to strike say a minute before show start, some systems however, won't let you do that.

One I worked on in Spain had it really cracked. 5Kw lamps behind Balantynbe Pro 35 (this is a 3D special venue set-up). The Super 80s had pneumatic cylinders fitted to the dowsers, as well as the projectors zippers. This was essential as the lamps were on all day. The SV automation opens the pneumatic dowsers fractionally before the zipper.

Posted by Steve Guttag (Member # 268) on 08-09-2002, 07:57 AM:

It is "the Kinoton way" to have the lamphouse powered via the projector and to have the lamphouse follow the motor when going in the forward direction.

You may, or may not have a lamphouse douser too...to Kinoton, they are extras...after all if the lamp is turning off with the motor, who needs em?

Another "feature" of the Kinoton system is that the lamphouse fans turn off when the lamp turns off, unless the thermal switch wants to keep em running until it cools sufficiently.

That being said, there is NOTHING to keep you or your technician from changing the hook up method to your suiting. All of our systems have the lamp turn on the "American" way. If you or the automation want it on, it comes on. If you or the automation want it off, it goes off. All of the ones we sell also have dousers in them too.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Pete Naples (Member # 761) on 08-09-2002, 08:50 AM:

Yes, I never connect Kinoton as Kinoton intended. I stick to the simple, or American way, ie The rectifier powers the lamphouse, you turn on the rectifier and the lamp strikes. I do however, wire in either a timer relay or a switch to allow the fans to run after the buld is shut down. Curiously enough the Erneman does this itself, the fans run for some time after shut down, and the it doesn't put the lamp out when the motor stops, it waits a couple of minutes, allowing for reel change, lens change or whatever. Never seen a Kinoton lamphouse without a dowser tho'!

Posted by Darryl Spicer (Member # 711) on 08-09-2002, 09:38 AM:

I usually pre-strike the lamp a couple of minutes before I hit the start button. This allows the lamp to settle down. I would also do that when I ran 6k changeover reels. I would pre-strike the second machine to allow the light to become stable for a flawless changeover. If you run 20 min reels you can just leave the lamp on and use the dowser on the lamphouse to protect the dowser in the projector.

Posted by John Pytlak (Member # 331) on 08-09-2002, 12:06 PM:

I've also been at unfortunate theatres where when the lamp strikes, you clearly hear the RF hash of the xenon ignitor in the sound system: "...Ssshzap..." --- Film done wrong!

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Paul G. Thompson (Member # 655) on 08-09-2002, 12:33 PM:

Proper grounding and RF suppression should remove the ignition noise from the sound system. Even if the CO douser is closed, the shutter can still catch hell if it is not rotating. Some projectors have very flimsy shutters, and a huge xenon lamp could frizzle the flimsey shutters in a matter of seconds. The majority of theatres I have seen have the igniter circuit energized upon motor start.

I don't like the idea of the bulb striking proir to motor start, unless the hand douser is closed. In remote-start houses, early lamp ignition proir to motor start could be a problem. Nobody is there to close the hand douser.

Pete, I never saw a system that had an automatic hand douser, but that could be an answer to frying shutters.

Posted by John Pytlak (Member # 331) on 08-09-2002, 12:49 PM:

One screening room at Kodak that I helped design has motorized dowsers fitted to Strong Super Lume-X lamps. They are also interlocked to close if the projector motor is not energized. A person in the front of the room can remotely start and stop the projectors, as well as adjust focus. The Century projectors have the operating and gear side doors safety-interlocked to prevent someone from starting them remotely with someone's fingers in harm's way. Also had selsyn interlock for showing side-by-side matched demos in perfect sync.

Posted by Scott Norwood (Member # 30) on 08-09-2002, 12:51 PM:

How long does it take for a xenon arc to fully stabilize? I'd guess that it would be well under a minute. (Carbon is a different beast, of course.)

In a manual booth with xenon lamps, I usually strike both of them several minutes before the show start (with hand dousers closed, of course) and leave them on until the end of the show. I'm probably just paranoid, but I like the idea of having a few minutes to fix the problem should a lamp fail to strike.

In automated booths, all of the automations that I've seen will strike the lamp when the operator hits "start" (or when the timer hits "0"), giving the lamp only about six seconds to strike before the changeover shutter opens.

Posted by Gordon McLeod (Member # 33) on 08-09-2002, 02:35 PM:

Many of the ORC M1000/M1600's had a rotary solinoid on the lamphouse dowser
many other situation I have installed have constant stall motors on the dowser that are slaved to the projector motor
Projector running dowser opens

Posted by John Pytlak (Member # 331) on 08-09-2002, 03:55 PM:

Gordon said: "Many of the ORC M1000/M1600's had a rotary solinoid on the lamphouse dowser"

Our screening room has three EASTMAN Model 30 16mm projectors equipped with those lamphouses and rotary solonoid dowsers too.

Posted by Matthew Bailey (Member # 601) on 08-09-2002, 04:10 PM:

Should the projector be set up to stop automatically if the lamp fails to strike?

Posted by Brad Miller (Member # 2) on 08-09-2002, 04:29 PM:

Some automations such as the CA21 do have that feature. As an example, if the lamp does not ignite within 5 seconds of the start cue, the entire system will do an emergency stop and sound the alarm. Very convenient.

Posted by Paul G. Thompson (Member # 655) on 08-09-2002, 08:43 PM:

I wonder about the cost/effectiveness/maintenance of these setups. I have never seen them.

Posted by Steve Guttag (Member # 268) on 08-09-2002, 09:51 PM:

The Strong CNA series automations also have the option for xenon sensors...they work too!

I have installed electric douser systems. Basically have the douser only open when the motor is running (pretty much what one would do anyway). When running automated or remote control shows, the electric douser has it's advantages. For the manual show, a manual douser is best.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Adam Fraser (Member # 1074) on 08-09-2002, 11:30 PM:

We have a Maxi 8x Automation and the lamp is set to strike (I think) just before the c/o opens. But as a precautionary measure we turn on the "Lamp" switch manually about 1 minute before showtime, if more than 1 minute the hand dowser on the xenon converted Magnarc gets closed. After the feature has started we flip the Lamp switch to off and the lamp stays on until we either close the c/o and manually shut off the rectifier or the failsafe shuts the lamp down when the tail runs through.

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Adam Fraser
www.pinestheatre.com