Film-Tech Forum ARCHIVE: Variable speed films

This is topic Variable speed films in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ralph Martin (Member # 4876) on 08-19-2009, 10:59 AM:

Hello all,

I want to be able to have the kids accompany some of the earlier silent films that run at different speeds. I figure our next step is to alter the speed of the projector for slower silent films (Century SA-TA).

A gentleman contacted me yesterday referred by Milestone Pictures. He said he will help me convert the theater’s projector to be able to handle variable speeds using a special variable transformer. It can be used without any hardwired installation so the projector can return to normal when our silent picture performance is over.

He said that there may need to be a three-blade conversion for the shutter to prevent the flicker effect depending on how slow the movie is to be run.

He’s from Chicago and has a very cool secret agent’s name :-)

He seems very knowledgeable and he’s willing to help us gratis.

Does all of this sound right?

Posted by Martin McCaffery (Member # 37) on 08-19-2009, 11:07 AM:

You won't find anyone better.

Posted by Gordon McLeod (Member # 33) on 08-19-2009, 02:26 PM:

It would not be a variable transformer but a motor driver controller
It would also entail that the motor on the projector be 3 phase
The other option is a servo DC motor conttol

Posted by Ralph Martin (Member # 4876) on 08-19-2009, 04:43 PM:

Yes, Gordon, I was corrected by him that it isn't, in fact, a transformer but a much different device that works for controlling the speed properly. So I misquoted him :-(

I wish I was more knowledgeable about these matters.

Thank you, Martin, for your input. I’m hearing from many that he’s top-notch.

Posted by Gordon McLeod (Member # 33) on 08-19-2009, 05:00 PM:

Since the speed of a AC motor can only varied by varieing the frequency which is howmost motor drive units work