Electronic intermittent

[Mark Gulbrandsen]

Here are pictures of the RCA FR 35B... Still looking for the schematic...

[Mark Gulbrandsen]

And here are the schematics...

[Adam Liberman]

If you want, I can send some photos of the insides of my EC and the motors there?

That would be great, thank you! I downloaded the operating manual for the FP30-E Premiere from archive.org, but it isn't a service manual and only has block diagrams.

[Christian Anner]

I have spoken to a couple of friends about the possibility of making film projectors with modern electronic intermittents. The motors you need are really quite unique and expensive, but luckily today you don't at least need to go and have them custom made as Kinoton needed to do in the late 80s for the original EC. For the ECII, I think they used an off the shelf motor, with their own control electronics in there. If you want, I can send some photos of the insides of my EC and the motors there?

Kinoton used out of the shelf motors. They where manufactured (or just labelled) by a company called "heidenhain" which makes CNC-machines. In the 1st EC machines there are servocontrollers for a horizontal-milling machine, even the "hand drive" knob is one of these. if you search for the numbers, you´ll find them all, but they´re expensive now (its 80s technology). Thats why in the ECs everything is on the "euro card" formfactor - industry standard then. For electronicans, these ECs are "easy to repair" if you know, which part you´ve got in your hand. (Yes, its complicated).

Later on, they changed in the E-Series to another drive. They built in the motors also where used by a dialysis-machine and other similar things for industrial speak its "just out of the shelf" they didn´t reinvent the wheel, they just put things together that where availiable at that time.
Roumors said, that Kinoton "stole" the invention of the electronic drive from other comapnies. As far as i know, ARRI produced the "loc pro" and befor the "arri pro" for angiocardiography which also has this type of electronic intermittend drive. Back in the days when i was at the lab at ARRI, we talked about that. Arri also have had 4 EC and EC II machines for free from Kinoton, who knows why....

[Neal Scanlan]

"I was interested in the first question asked by Adam. I asked ChatGPT to design a servo/stepper motor capable of achieving 24 steps/movements in one second. I also asked that acceleration, degree of rotation, and deceleration be parameters that could be finely tuned. The answers are staggering. Further questions I asked about specific motors, driver options, and code were also answered in a precise way. I have no doubt that using AI as a guide, one could with modern motors and electronics produce a very successful projector."

[Josh Jones]

Roumors said, that Kinoton "stole" the invention of the electronic drive from other comapnies. As far as i know, ARRI produced the "loc pro" and befor the "arri pro" for angiocardiography which also has this type of electronic intermittend drive. Back in the days when i was at the lab at ARRI, we talked about that. Arri also have had 4 EC and EC II machines for free from Kinoton, who knows why....

IP theft is the most sincere form of flattery....

[David Ferguson]

Interesting - if true it would be quite ironic, as I know that Sondor first licensed the EC from Kinoton to make their Nova projector, and then at some point down the line, stopped licensing it and started selling a clone instead! Kinoton were not happy about this - so if they were "inspired" (or more) by Arri, that would be quite ironic.

Christian, do you know when the ARRI Loc Pro was manufactured?

[Christian Anner]

David, afaik the arri-pro and later the Loc Pro was manufactured at the Arri works in the Theresienstraße in Munich between the mit 80s and 2000. Theresienstraße is the place where the small foundry was. Some alloy-parts where made in Stephanskirchen near Rosenheim (where i live), this subsidary is now closed since the 1st of october.

Here the part of the manual which is the most important in there:

Fast film transport and simple operation: The film is transported by a motor with a directly-driven double-sided sprocket wheel. This patented intermittent film drive system is acute to less than 0.01 seconds at any projection speed. Constant film tension and safe film transport are ensured by computer-controlled drive motors for both film carriers. The “auto-stop” feature stops the film automatically 6 ft (2 m) before the end of the film.

Its too sad, but arri goes far away from its cinematic background and turning into a "video camera" sales-store. Former "Arri Media" which included the Lab, is now known under the "pharos" label here, but the old ones are still there.
Some of my old colleques now are in the beer brewing business or beeing retired for years know. I was the youngest guy back then, learned everything just as Mr. Arnolds advice "show him how it goes" i was the last one who learned the Lab-guy things then. After a few years there, i went to Bavaria, but just for a few hours a week, my main job was in a Cinema in Munic. Since digitalisazion in 2013 i´ve learned the same thing as my parents (and that i said as a teenager i will never ever do) public administration

But back to topic: If interested i will post some pictures of the internals of the EC series, i´ll try to get the part numbers on it.

[Ryan Gallagher]

IP theft is the most sincere form of flattery....

That is funny cause if one designs one with ChatGPTs guidance expect it to commit IP theft as well (via its training data). ;-)

[Scott Norwood]

What is the advantage of an electronic intermittent in practice? Other than infinite framing ability, in-path rewinding, silent films (the shutter spins 50% faster under a certain frame rate, to give a 3-blade shutter effect), and multi-format machines (all fairly niche use cases), what does it offer? The mechanical Kinotons seem to be at least as steady as the electronic ones (in practice), and the electronic version adds a significant amount of complexity.

[Steve Guttag]

In practice, the Kinoton E projectors can be steadier. Where we have E projectors they use them in multi-format machines, reverse-wind on them and definitely do variable speed, even on the fly. There is nothing wrong with using a mechanical intermittent in a straight-up 35mm 24fps system.

The downsides are the life-cycles of the stepper motors and related monitoring systems. A well oiled mechanical intermittent should last most people, now, a lifetime. With Kinoton (and Ballantyne) you still have that framing coupler to wear on the mechanical intermittents.

For silent and other slower running film, the electronic intermittent has distinct advantages as the film is not exposed longer to the hot xenon lamp since the dwell time isn't necessarily also expanded.

Another advantage can be the speed of the intermittent acceleration can result in a more light-efficient system. Kinoton's "FPS" systems (Premiere and Reference) made from 2007 onwards were notably more light efficient.