DC Motor for DIY 16mm Telecine?

[electrodist]

Hello, I am working on a converting a Eiki SSL-0 into a multi-speed telecine that works much like Roger Evan's workprinter. I would like to be able to control the speed through a PWM device, so that it can go between 2 and 24FPS. This would require changing out the AC motor and power supply for DC components. Also the pulley gears and belt will be swapped out to change the timing. I am at a loss on what motor to purchase for this modification, or even where to purchase such a motor. I don't know much about torque ratings and how much of a load the Eiki produces. Does anyone know what kind of motor is needed to achieve this speed range? Or a good DC motor supplier?

My end goal is to produce a HD telecine that will work with my HVX200, Mac, and Capturemate.

Here are some test frames of the capture, lighting, and optics on the motorless unit. The images were recorded at DVCPro 720P HD. They come in with pillar bars which were later removed. The images are from the Cuban Revolution and Vietnam war for a documentary I am putting together.

http://robertcauble.com/where_is_the_sun_5.html

http://robertcauble.com/where_is_the_sun_4.html

http://robertcauble.com/where_is_the_sun_3.html

[JhnZ33]

Hello, I am working on a converting a Eiki SSL-0 into a multi-speed telecine that works much like Roger Evan's workprinter. I would like to be able to control the speed through a PWM device, so that it can go between 2 and 24FPS. This would require changing out the AC motor and power supply for DC components. Also the pulley gears and belt will be swapped out to change the timing. I am at a loss on what motor to purchase for this modification, or even where to purchase such a motor. I don't know much about torque ratings and how much of a load the Eiki produces. Does anyone know what kind of motor is needed to achieve this speed range? Or a good DC motor supplier?

My end goal is to produce a HD telecine that will work with my HVX200, Mac, and Capturemate.

Here are some test frames of the capture, lighting, and optics on the motorless unit. The images were recorded at DVCPro 720P HD. They come in with pillar bars which were later removed. The images are from the Cuban Revolution and Vietnam war for a documentary I am putting together.

http://robertcauble.com/where_is_the_sun_5.html

http://robertcauble.com/where_is_the_sun_4.html

http://robertcauble.com/where_is_the_sun_3.html

Nice stills. As far as the motor, can't help you there as I am curious myself. What are you using as a light source? Would like to see a photo of your conversion handywork so far.

John

[electrodist]

Thanks JhnZ33. I will post images once I get the thing put together more.

As for the light source, I use a 75W MR16 Halogen off the original power feed and fixture. This fixture originally pointed the bulb directly at the film gate. I removed it from the chassis and pointed it, facing down, into a small light chamber with a 45 degree bounce directed at the film gate. The chamber is made of wood and the interior is completely covered with white office paper. The output end (in front of the film gate) is covered with opal glass, purchased from Edmunds Optics. The result is a very soft and diffused 2" square light source.

I tried different watt bulbs, and 75 seems to produce the best image.

Turning back to the motor question, I found out some specs on the original Eiki motor. Perhaps this would be helpful for a more mechanically inclined person.

1/20HP so 37.3 Watts
100-120VAC
starting torque 1.6kg/cm or 8.99lbs/inch
rated torque 0.8kg/cm or 4.48lbs/inch

I figure I need a motor between 1000 and 3000 rpms, based on usable gear ratios. Also a 12-24VDC would be ideal because of power supply and pwm kits available. I can't figure what kind of torque is necessary to keep it going at, say, 1/10 speed. Am I necessarily looking at a gearhead motor for this task?

[VideoFred]

Hi Electrodist,

Please do a search here for RCBasher's postings. Frank is using a very nice DC motor. No need for a gearbox, just some pullys and a belt. Unless you want to run very slow.. But PWM will solve this.

I am using DC car wiper motors on my 8mm machines.. Maybe the heavy models will work on 16mm machines. 16mm machines are needing pretty much power. Maybe you will need a belt with teeth..

For more details, please have a look at my website, the machine vision camera page. A bit of English translation is amongst the text. You will see the wiper motor-friction wheel solution on my R8 machine. I have the same solution on my S8 machine too, now.

My website needs a good update, I'm getting much better quality, now.

E64T, Canon 814 XL-S, in my garden this summer,
Transfer with led backlight source: (heavy Jpeg compression)


Fred.

[RCBasher]

This is the motor I used for my 8mm conversion http://tinyurl.com/32odlq

Follow the www button below for pictures, including the link in the Updates section for my Eumig 610 D conversion.

I have no way to know how much torque you will need...and I didn't know how much I needed for my conversion, so I selected a similar wattage motor to the original. As it turned out, the new motor is very efficient and I would have probably been ok with one half the size. Anyway, the nice thing about this motor is it already has built in regulation and speed control with a 30:1 ratio...so no change of gearing required to cover your desired speed range. Hope this helps.

Frank

[alex-rus]

Hi Electrodist,

Please do a search here for RCBasher's postings. Frank is using a very nice DC motor. No need for a gearbox, just some pullys and a belt. Unless you want to run very slow.. But PWM will solve this.

I am using DC car wiper motors on my 8mm machines.. Maybe the heavy models will work on 16mm machines. 16mm machines are needing pretty much power. Maybe you will need a belt with teeth..

For more details, please have a look at my website, the machine vision camera page. A bit of English translation is amongst the text. You will see the wiper motor-friction wheel solution on my R8 machine. I have the same solution on my S8 machine too, now.

My website needs a good update, I'm getting much better quality, now.

E64T, Canon 814 XL-S, in my garden this summer,
Transfer with led backlight source: (heavy Jpeg compression)


Fred.

It is a fine sample 64T with Canon camera!
You can show full resolution frame?

[JhnZ33]

Looking at the specifications for both motors, they are similar. The 24V motor Frank uses is just slightly under the starting torque of the Eiki. Course the torque rating of the 24V motor looks to be a continuous rating, so I'm not sure if the start-up torque would be different or not.

Frank can correct me on this, but I presume you would lose some torque if you electrically slow the speed of the motor. This may or may not affect performance. You could always try it as a straight replacement first, and if you have issues and you plan on slowing the drive of the projector down from 24 fps anyway, I would use a little smaller pulley on the motor and a little larger pulley on the main shaft. That would help gain some torque.

You would have to calculate the approximate size pulleys for the maximum fps, but that should be no big deal. Looks like the rated load speed is 3000 RPM, providing you don't reach the torque limits of the motor. A ratio of 2.08 to 1 reduction is needed for 24 fps @ 3000RPM.

John

[VideoFred]

It is a fine sample 64T with Canon camera!
You can show full resolution frame?

Sure I can do that, Alexander!
But not here, I do not want to hijack this thread.
I will post it here:
viewtopic.php?t=18059

Fred.

[RCBasher]

Course the torque rating of the 24V motor looks to be a continuous rating, so I'm not sure if the start-up torque would be different or not.

Frank can correct me on this, but I presume you would lose some torque if you electrically slow the speed of the motor. This may or may not affect performance.

The torque is fairly wide spread and I can say that if you just apply power to the motor without it being clamped down, the startup torque will shoot the motor clean off the table...it happened to me :oops:

Frank

[JhnZ33]

The torque is fairly wide spread and I can say that if you just apply power to the motor without it being clamped down, the startup torque will shoot the motor clean off the table...it happened to me :oops:

Frank

Runaway motor! 8O :lol:

[RCBasher]

The torque is fairly wide spread and I can say that if you just apply power to the motor without it being clamped down, the startup torque will shoot the motor clean off the table...it happened to me :oops:

Frank

Runaway motor! 8O :lol:

Yes, but the autobrake cut in when it pulled the wires off the powersupply! :lol:

[super-8-epiphany]

[quote="electrodist"] Does anyone know what kind of motor is needed to achieve this speed range? Or a good DC motor supplier?




I have brand new NOS 12 volt DC Matsushita drive motors- that I stock for audio/stereo tape deck repairs- one of my other hobbies. These are 1970-80's vintage, I've installed dozens in tape decks and they are really torquey and do the job well. They are OEM in the old 8-track stereo cartridge tape recorders, and some cassettes as well- and would pull along heavy 1/4" wide audio tape that was on a 3.5" endless loop spool inside the cart, at 3.75 IPS. On fast forward they go 11.25 IPS (inches per second)

these motors are powerful yet compact enough to fit inside small electronics. If you put a variable resistor in line with it, you can adjust the speed. The motor shaft has no pulley on it, but I can install one if you like. These motors typically ran a wide belt that then drove the tape capstan, pulling audio tape past the play/record heads. They should work just fine for film as well, as they have delicate speed control mechanism inside that holds speed constant for given voltage and load. These motors are a few times larger than the typical drive motor in a vintage high-end super 8 camera- so they are plenty powerful enough.

here is a picture- these motors can fit inside your hand closed- and it wired for both standard speed and fast forward- the price is only $10 plus $3 shipping. At one time I had 175 of these, now it's down to 50 or so- so if you want one don't wait too long- eventually they will sell out.

You can also low-buck is and just strip one of these out of an old tape deck- but it may be worn and tired.

PM me if you are interested.

[JhnZ33]

We need to remember this is 16mm we are talking about, not 8mm. I don't know if a tape deck motor will have enough torque to sufficiently drive the mechanics of this projector with the weight of 16mm film as well. I own 2 of these projectors and there is quite a bit of load on the drive system. The 12 volt motors I use for my 8mm machines have enough torque for 8mm, but fall way short for 16mm and they are quite strong motors.



For 16mm, I think you would need something like the motor Frank is using.

John

[VideoFred]

For 16mm, I think you would need something like the motor Frank is using.

I agree with that, maybe even a type stronger than Franks.

John, you build wonderful mechanical things!
What brand of motor(s) do you use?

Fred.

[JhnZ33]

I agree with that, maybe even a type stronger than Franks.

Maybe, but I think the motor Frank is using is a suitable canidate. Only one way to find out - who will be the first to order and implement one of these bad boys? Unfortunately, it won't be me at this time.

John, you build wonderful mechanical things!

Thanks Fred. As you know, most of these fabrications are done using very simple tools, as I have to use what I have.

What brand of motor(s) do you use?

Fred.

These are Merkel-Korff Industries 12 volt motors. They spin at 3500 RPM no-load speed. The case is roughly 3.25 inches in length and 1.5 inches in diameter.

John