Film-Tech Forum ARCHIVE: masking motor speed.

This is topic masking motor speed. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Bernie Anderson Jr (Member # 410) on 11-07-2007, 03:38 PM:

I'm trying to use a ACD "Tom Thumb" masking motor to power a top and bottom masking set up for a private screening room. The design will work, but I was wondering if there was a way to slow down the motor so it doesn't whip the masking closed. This thing flies. Any suggestions? Do they make different size cogs to change the speed?

Thanks

Bernie

Posted by Steve Guttag (Member # 268) on 11-07-2007, 05:21 PM:

ADC motors are not known for their variable speeds...particularly the Tom Thumb models...which tend towards their lower end side. Normally the sprocket is rather small and moves side masking at a respectable rate. I can see where T/B masking would be moving a bit brisk...especially in a screening room environment. One thing I like about MDI motors is the ability to set the speed and for T/B I never go above the slowest setting (1). Then again, for sides, I normally don't go above 2.

Steve

Posted by Gordon McLeod (Member # 33) on 11-07-2007, 05:56 PM:

I often put a block and tackle in since the double purchase of the tackle will reduce the load on the motor and slow down the rate of travel

Posted by Richard Fowler (Member # 893) on 11-07-2007, 06:56 PM:

The ADC Tom Thumbs ( 4 models ) have an average speed of 5 inch per second of travel. Gordon's suggestion of block and tackle reduction does work if counterbalanced correctly with proper pullies.