Film-Tech Forum ARCHIVE: Kinoton FP30 and Strong Alpha Platters

This is topic Kinoton FP30 and Strong Alpha Platters - timing and adjustments 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=004541

Posted by Matthew Nock (Member # 1575) on 02-13-2003, 06:53 AM:

Hi all!

We have just installed two very nice little Kinoton FP30's to replace our Simplex projectors.

However, we have run into a little bit of a problem...

The Kinotons stop a lot quicker than our simplex machines did, and and such, the "dancer arm", "Yo-yo", "jockey" (whatever else you wanna call it) comes up very suddenly, and the takeup platter does not slow down quick enough.

How do we change where in the path the platter should commence its slow down? I know that we can adjust the variac to change where it has its failsafe cut-off, but I couldnt find anything in the manual about what I am trying to do.

Any help, suggestions?

Cheers,

M@

Posted by Richard Fowler (Member # 893) on 02-13-2003, 10:43 AM:

If this projector is a fairly recent model with the invertor drive system ( which Kinoton was first to implement into most of their systems [Smile]

) the drive controller ramp down speed could be adjusted to slow more gradually. electromechanical variac platters such as Potts, Strong, et cetera are not able to stop smoothly during the initial 5 to 10 minutes of operation. Call your tech to do the adjustments.
Richard Fowler
Kinoton America Inc.

Posted by Matthew Nock (Member # 1575) on 02-14-2003, 10:06 AM:

Hi Richard,

Thanks for the quick response. I have a feeling that our machines will not be using the invertor drive system - the machines where manufactured in 1987.

It seems that the problem is very much more platter related than anything else. I noticed tonight that the unstable "dancer-arm" movement was also apparent upon starting a show. As you have said, the take a while to stabalise..

It appears that because the start and shutdown of the projector is so quick, it seems that the platter isnt able to "keep up".

Anyone had any experience with these sort of problems with strong platters?? There must be a work around for this [Smile]

Cheers,

M@

Posted by Daryl C. W. O'Shea (Member # 1303) on 02-14-2003, 10:19 AM:

A question... why is the projector stopping with film in the machine? Does it not tail out at the end of the show?

To stop a projector manually while using Strong platters (or any variac controlled platter) I usually just grab the take-up deck to slow it down when I hit the stop button. Sometimes this requires a bit of running... or a bit of a dash to the platter.

Posted by Brad Miller (Member # 2) on 02-14-2003, 11:51 AM:

I think Matthew is trying to thread up the film, then motor down to the starting point. Sounds to me like his automation simply can't operate off of a start cue.

So long as you have Strong platters, you are pretty much screwed in this regard. What kind of automation do you have? Maybe it could be set up for a start cue, which would eliminate your problem.

Posted by Dave Macaulay (Member # 813) on 02-14-2003, 12:15 PM:

This is usually a problem with Cinemeccanica V4s as well, they stop fast too. Stopping with the supply platter full is not good, starting up is OK as long as it doesn't pull totally tight or drop the platter dancer to shutoff, the dancer will ride around a lot but should settle down. The drive motors have a lot of power but not much drag to stop a turning platter!
Altering your startup routine to avoid stopping - using start cues or adjusting leaders and start delay time - is your best approach.
You can add an accumulator between the projector and platter but this is a pain to get/build/install and to use.
Or attach a big flywheel to the projector motor, like Simplex does.

Posted by Rick Long (Member # 213) on 02-15-2003, 11:02 PM:

As Dave says, Cinemeccanica projectors (including Vic 5's and Vic 8's have this problem when used with Strong platters.

The best way, if possible, it to re-work your automation so that it doesn't stop till the film tails out (as long as the change-over closes when it should).

Failing this, another solution used, is to manally switch the motor to manual over-ride during the credits. The motor will continue running until you return the switch to the auto position.

With one type of automation we had, which allowed projectors to stop with a cue, the cue was put on the tail-piece about 3 frames from the very end of the print. As it was a peg-board automation, all other functions happened at the appropriate time.

Posted by Mark Gulbrandsen (Member # 72) on 02-16-2003, 11:27 AM:

This is actually a problem with using any machine that slows down quickly when using with the Strong/Potts platter. You cannot compensate for it unless you have the invertor drive feature on your machine. You will have to act as the brake and slow down the deck by helping it stop yourself.
There are alot of machines that have this unfortunate rundown problem.
Mark @ CLACO

Posted by Joe Redifer (Member # 3) on 02-16-2003, 11:42 AM:

Use the bigger Strong center ring for takeup at all times instead of the pansie-assed wimpy small ring that is included with the platters. It was mentioned in my review that the platters should come with the bigger rings instead of the small ones.

Posted by Brad Miller (Member # 2) on 02-16-2003, 12:12 PM:

Good one Joe. I had forgotten about that. However, I will warn Matthew that if he uses the large center rings, he has to be extremely careful when he is threading and pulls tension on the takeup elevator, as it will take off and break rollers off of the platter if you are not careful.

What a great design. [puke]

You know, all Strong has to do is extend the height of the elevator! [Mad]

Posted by Jack Ondracek (Member # 1466) on 02-16-2003, 03:59 PM:

quote:
You know, all Strong has to do is extend the height of the elevator!

I don't think it would be that simple, Brad.

Platters that use gear reduction motors have a much more positive control over momentum, both starting and stopping, which is the basic problem here. The Strong/Potts/CFS/D&M platters, are challenging because the motor does little to slow the platter down once voltage is removed... and they take so long to build up speed that they're doing the 50 yard dash by the time they catch up to the projector... all this well known to everyone here.

The problem with extending the elevator rails is the variac itself. It's already at zero output by the time it hits the top right now. You'd have to rework the linkage somehow(?) or come up with some spring loaded arrangement that would allow the elevator to continue traveling past the variac's stop point.

Basically, these vacuum cleaner motors just don't have enough starting torque to allow the takeup platter to keep up with a fast starting projector... and I'm just waiting for the day the feed platter tries to frisbee the print! [Eek!]

Give this one to ORC & their herky Bodine rim drives... I never had that problem with that part of their design. Those gear reduction motors have a lot more control over the platters & have no problem keeping up with the projector.

Posted by Brad Miller (Member # 2) on 02-16-2003, 04:44 PM:

I'm not suggesting Strong extend the length of the elevator's travel in relation to the variac, only extend the top so there is a few extra feet of play where the speed is at 0. It shouldn't be too difficult to redesign the arm that couples to the variac to allow for an extended elevator. Heck, they could even make it so that the variac has a counterweighted arm that protrudes from the control box and the elevator literally pushes it down (increasing it's speed). Then they could make the rods as long as they wanted because once the elevator rollers reached a certain height, it would raise up off of the arm. A simple modification like this would definitely be cheaper for Strong to do then redesign the takeup entirely, hence my comment.

If nothing else, add a spring to the top of the elevator to help slow down the platter. While I don't really like that idea, it's better than the way it is now.

Posted by Gordon McLeod (Member # 33) on 02-16-2003, 05:12 PM:

Actually the red specos and the teco platters also had problems with fast starting and stopping machines

Posted by Jack Ondracek (Member # 1466) on 02-16-2003, 07:00 PM:

quote:
from Brad:
I'm not suggesting Strong extend the length of the elevator's travel in relation to the variac, only extend the top so there is a few extra feet of play where the speed is at 0.

Guess that's where you lose me.

If the variac is a zero, and is against its stop, you could have 20 feet of extra rail, but the rollers couldn't use it because of the variac limits preventing further upward movement.... yes??? no??? ???

Posted by Brad Miller (Member # 2) on 02-16-2003, 07:15 PM:

Now you've lost me.

Let's say the current rails are one foot tall (which is about right). If they were extended to be 3 feet tall, but only the bottom foot would make the motors spin and the top 2 feet were "zero speed", that would give enough stop time. Alternatively they could add one more roller like SPECO did on their later LP270s. The idea here is to get more spindown time before the elevator crashes.

Posted by Daryl C. W. O'Shea (Member # 1303) on 02-16-2003, 11:06 PM:

Jack is saying that since the arm attactched to the variac will prevent the carriage from rising past a height (the current top of travel) since the variac itself can only rotate so far before stopping.

This however, could be taken care of by attatching the arm to the carriage in a long slot and attatching a spring to the arm in the slot. Normally the arm would ride, with the carriage, at the top of the slot on the carriage. But when the carriage is pulled higher, the arm would slide down the slot (stretching the light spring). This way, you could use the same variac and arm and still have the extra travel.

Of course this would only be better than adding an additional pair of rollers to the whole assembly, if you could get an extra half of the current travel out of it.

Posted by Brad Miller (Member # 2) on 02-16-2003, 11:12 PM:

Ok, then I did understand him. (See my post above.) It can be easily worked around if Strong ever cares to.

BTW, Christie makes a retrofit kit to fix all of the issues with the Strong design. Call them up and tell them you want a complete AW3R kit. [Big Grin]

Posted by Jack Ondracek (Member # 1466) on 02-18-2003, 09:16 PM:

quote:
from Brad...
...Christie makes a retrofit kit to fix all of the issues with the Strong design. Call them up and tell them you want a complete AW3R kit.

I assume this particular conversion/retrofit involves direct replacement of pretty much all the original components, eh? [Big Grin]

Posted by Matthew Nock (Member # 1575) on 02-19-2003, 01:10 AM:

SO this retrofit kit is available from where exactly?

the only site I can find for Christie is ChristieDigital.com.

Anyone have an idea of price?

Posted by Brad Miller (Member # 2) on 02-19-2003, 02:03 AM:

Here is the direct link, Matthew. You want part #193932-001