Arri 16s 400ft torque motor conversion to 12 volt

[Pete Von Tews]

Hello everyone,

 

I am using a 12 volt battery with my Arri 16s/b and things are running fine with the internal 100ft loads. However last weekend while shooting with the 400 foot mags, I ran into trouble because the magazine was pulling on the film too hard and causing havoc. Eventually things worked better by slowing the take up reel by using my index and thumb on the knurled rotating part but that is not a permanent solution and burns the fingers!

 

Can anyone help me find the directions to convert the motor to 12 volts or limit the voltage coming into the motor from 12v to 8v?

 

Would a resistor work?

 

thanks~!

 

-pete

[Keneu Luca]

I have 2 torque motors that have both been converted to 12 volts.

 

But one of the motors was giving me trouble. Sometimes it wouldn't run. If you want to buy it from me, real cheap of course, and perhaps you can take it apart and see what needs to be done for the conversion. Maybe you'll even be able to fix the problem with the motor I sell you.

 

I dont know. Maybe its worth considering. If not, its cool :)

 

Im sure Mr. Carroll will chime in here and offer a better alternative. :)

Edited December 17, 2009 by Keneu Luca

[Ed Sieb]

Hello everyone,

 

I am using a 12 volt battery with my Arri 16s/b and things are running fine with the internal 100ft loads. However last weekend while shooting with the 400 foot mags, I ran into trouble because the magazine was pulling on the film too hard and causing havoc. Eventually things worked better by slowing the take up reel by using my index and thumb on the knurled rotating part but that is not a permanent solution and burns the fingers!

 

Can anyone help me find the directions to convert the motor to 12 volts or limit the voltage coming into the motor from 12v to 8v?

 

Would a resistor work?

thanks~!

-pete

It might. The problem with resistors is that they're not linear with regards to current drain. So long as your current drain from the motor is constant, the voltage drop will be also. The other problem with resistors is that they might limit current too much, and kill any torque in the motor, rendering it too weak.

 

A better alternative is an 8 volt votage regulator with a pass transistor to handle the current. This is what the Arri transistorized motor did, and what Tobin did as well. The circuit is actually quite simple, and the parts count small. If you're experienced in electronics, it's a snap, otherwise, get a electronics tech to build it for you. I'll see if I can dig up a schematic. (No guarantees!) :unsure:

[Ed Sieb]

OK - cheap solution (less than $15.00).

Go to this website:

http://www.electronics123.com/s.nl;jsessio...it=A&id=432

and purchase the voltage regulator kit.

It looks like this:

Schematics and documentation:

http://www.electronics123.net/amazon/datasheet/k60.pdf

 

You'll need a minibox to put it in from Radio Shack.

 

Will provide 8 volts at 1 ampere. Case closed.

 

Alternatively, if that's not available, just buy a 7808 voltage regulator IC from Radio Shack. requires two other parts (small capacitors). Get a tech to build it for you.

[Tim Carroll]

Hello everyone,

 

I am using a 12 volt battery with my Arri 16s/b and things are running fine with the internal 100ft loads. However last weekend while shooting with the 400 foot mags, I ran into trouble because the magazine was pulling on the film too hard and causing havoc. Eventually things worked better by slowing the take up reel by using my index and thumb on the knurled rotating part but that is not a permanent solution and burns the fingers!

 

Can anyone help me find the directions to convert the motor to 12 volts or limit the voltage coming into the motor from 12v to 8v?

 

Would a resistor work?

 

thanks~!

 

-pete

 

Hi Pete,

 

There's two things going on here, first, your torque motor needs to be converted to handle the 12 volt battery pack, and second, after it is converted, the torque motor may need adjustment.

 

You convert the torque motor to handle the 12 volts so that the 12 volts don't burn up the torque motor which was designed to only handle 8 volts. Clive Tobin used to do that conversion, you may want to talk to him.

 

A torque motor is not a direct gear driven connection to the take up reel. If it were, it could not accommodate the change in take up reel rotational speed as more and more film accumulated on the take up reel. It is a torque motor, meaning it applies a controlled amount of torque to the shaft of the take up reel, so the take up reel is evenly attempting to "take up" the film slack. That torque may need adjusting so that it isn't "pulliing" to hard on the the film.

 

Hope that makes sense.

 

Best,

-Tim

[Pete Von Tews]

Thank you for all your answers. I'm going to look into making a voltage regulator. I like to solder and fix stuff myself so It will be fun. Oh, and how do you adjust the torque in the motor? Seems like its all connected with gears and no "clutches"...

[Tim Carroll]

Thank you for all your answers. I'm going to look into making a voltage regulator. I like to solder and fix stuff myself so It will be fun. Oh, and how do you adjust the torque in the motor? Seems like its all connected with gears and no "clutches"...

 

Been a while since I rebuilt one of those, been doing mostly 16BL, 16M, and ARRI III mags for the last few years. Can't remember if they're felt clutches or spring washer clutches, but there are definitely clutches in there.

 

I'm no longer servicing those, you might want to send it to Axel Broda, as they're not really a user serviceable part.

 

Best,

-Tim

[John Sprung]

I'm going to look into making a voltage regulator.

 

That sound like a good way to go. You could make it switchable, so you could run the torque motor on either 8 or 12. DC regulators are readily available, try DigiKey.

 

 

 

 

-- J.S.

[Pete Von Tews]

Hi everyone. Happy new years!

 

On line I found plans for this voltage regulator, but after hooking everything up, and trying to start the motor, the led on the regulator just dims and the motor does not turn. (I did modify the plans for a 8volt operation) Maybe someone good with electronics can help me out...

 

http://www.mybitbox.com/articles/standalon...tage-regulator/

 

thanks!

[John Sprung]

The LM7808 regulator is good for 1.5 Amps. Do we know for sure that that's enough for the Arri torque motor? Measure the output with a voltmeter under no load, and again with the motor connected. What do you get?

 

 

 

-- J.S.

[Ed Sieb]

The LM7808 regulator is good for 1.5 Amps. Do we know for sure that that's enough for the Arri torque motor? Measure the output with a voltmeter under no load, and again with the motor connected. What do you get?

-- J.S.

In the event that 1.5 A is insufficient, the 7808 can be directly replaced with a 7808H, which is good for 3 A.

This type of regulator circuit is dead simple. The only reason for a severe voltage drop under load is that the DC source has insufficient current capacity. If building such a regulator, I would ensure that I had at least 3A minimum current capacity in my DC source. Make sure the 12V battery feeding the regulator is fully charged!

 

Alternately, you can use an AC source (transformer and rectifiers) to provide the DC. Good for indoor and filming on sets.

[flavio filho]

Hi everyone. Happy new years!

 

On line I found plans for this voltage regulator, but after hooking everything up, and trying to start the motor, the led on the regulator just dims and the motor does not turn. (I did modify the plans for a 8volt operation) Maybe someone good with electronics can help me out...

 

http://www.mybitbox.com/articles/standalon...tage-regulator/

 

thanks!

 

 

Hi Pete/Ed.

 

I have the same problem now... 4 ARRI 16S MAGS to convert. Too pricey. I'd rather try the conversion.

 

Do you guys have any details/list of circuits/stuff to buy and go for it?

mean, if I buy the circuit Ed mentioned (which one would actually be?)

Just need to know some details so I can look onto it with something to start from.

 

Please let me know.

 

Best,

 

Flavio

Edited November 1, 2011 by flavio filho

[flavio filho]

Hi again.

 

I just saw one of the 4 motors I have has 12V TCM written inside it. To be sure about them all, will have to test the voltage...

So, I wonder how would be possible to test the voltage of them? I have to have a voltage meter of course, but where I should touch the tips?

 

And how to do hat without plugging into a battery? With the risk to burn it plugging the only 12V I have onto a 8V?

 

Thanks,

F

[Charlie Peich]

Hi again.

 

I just saw one of the 4 motors I have has 12V TCM written inside it.

 

Hello again Flavio...

 

Does the torque motor you have with the 12V TCS label look like this?

 

 

 

If so, then you have a torque motor that has been converted to 12 volt operation by Tobin Cinema! You are good to go with the 12 volts to your camera, you don't have to make any conversions to the other magazine's torque motors.

 

You do realize that ONE torque motor can be used on several 400 foot magazines? You don't have to have a torque motor on every mag, just take the motor off the spent mag, and put it on the next freshly loaded mag. Many kits would have 2 or 3 mags with one motor to be used between them. It was cheaper and it cut down the size and weight of the cases.

 

However, if you are shooting fast and burning through 11 minuets of film and reload time is important to capture an uncontrollable event, it IS slightly faster reloading to have a motor on all the mags, one less step when changing the mags on the camera, and one less step when reloading the mags. Also, it's nice to have a back up torque motoer motor, but do you have a back-up camera drive motor?

 

Have you checked the other motors to see if they have been converted?

 

For your upcoming shoot, will you be loading 4 - 400ft loads at one time? Will you be shooting more that 1600 ft a day (44 minuets screen time)? Will you be doing 11 minuet takes? 3-5 minute takes? Will you have a loader to reload mags while you are shooting?

 

Hand holding? 400 ft mags on the 16s add more weight and shakiness. A body brace would help.

 

There are times when the 16s with 100 ft loads can be easier to use.. faster. But, it depends on what you are shooting.

 

Charlie

[flavio filho]

Hello again Flavio...

 

Does the torque motor you have with the 12V TCS label look like this?

 

 

 

If so, then you have a torque motor that has been converted to 12 volt operation by Tobin Cinema! You are good to go with the 12 volts to your camera, you don't have to make any conversions to the other magazine's torque motors.

 

You do realize that ONE torque motor can be used on several 400 foot magazines? You don't have to have a torque motor on every mag, just take the motor off the spent mag, and put it on the next freshly loaded mag. Many kits would have 2 or 3 mags with one motor to be used between them. It was cheaper and it cut down the size and weight of the cases.

 

However, if you are shooting fast and burning through 11 minuets of film and reload time is important to capture an uncontrollable event, it IS slightly faster reloading to have a motor on all the mags, one less step when changing the mags on the camera, and one less step when reloading the mags. Also, it's nice to have a back up torque motoer motor, but do you have a back-up camera drive motor?

 

Have you checked the other motors to see if they have been converted?

 

For your upcoming shoot, will you be loading 4 - 400ft loads at one time? Will you be shooting more that 1600 ft a day (44 minuets screen time)? Will you be doing 11 minuet takes? 3-5 minute takes? Will you have a loader to reload mags while you are shooting?

 

Hand holding? 400 ft mags on the 16s add more weight and shakiness. A body brace would help.

 

There are times when the 16s with 100 ft loads can be easier to use.. faster. But, it depends on what you are shooting.

 

Charlie

 

 

Hi Charlies.

 

Thanks.

 

Yes, I know I can use the same Motor for all Mags, what's excellent.

It's just me being perfectionist. But I'd like to AT LEAST convert another one... Then I have two and no need for any more.

I'll probably sell the other 2 mags, and getting the two newest ones. That is more than enough I believe to make some short films from now on.

 

I didn't check the others to be honest. I'm not much of an electrician. So I have to know how to test them. Do you have an idea?

I'm aware about the weight of the 16s... I do have a shoulder support, that does it well.

 

And I won't use more than a 400ft for SURE. Will probably take another 100ft for scenes holding the camera running behind the actors with a SteadCam Merlin I will borrow.

Main thing for me now is to FIX the "B" Arri I have (not working)... BUILD 2 battery packs... Then AFTER convert one of the motors. And probably sell the other 2 (or keep them an one day could sell the Arri 16s "B" with two mags.

 

Well, too much to do. And too little to spend...

 

Thanks,

F

[Tim Carroll]

 

Damn Charlie, is all your equipment in that pristine of shape? That is impressive sir.

 

Best,

-Tim

[flavio filho]

Damn Charlie, is all your equipment in that pristine of shape? That is impressive sir.

 

Best,

-Tim

 

 

Damn, it is. Really pristine.

I wonder you guys would give me some advice to convert my other Mag to 12V?

I just need to know what circuit to buy and what to do. I have one converted to 12V already, so I could do by comparison.

 

Pls let me know.

 

Ta,

F

[Charlie Peich]

I just need to know what circuit to buy and what to do. I have one converted to 12V already, so I could do by comparison.

 

Pls let me know.

 

Ta,

F

 

 

Flavio,

 

The electronic components needed to reduce the 12 volts down to the 8 volts for the torque motor are:

 

1 - 5 watt 3 ohm wire wound ceramic resistor. Like this. This is for reducing the voltage.

2 - 103M ceramic disc capacitors. A capacitor marked 103M is a .01 uf +- 20%. I think the R stands for the rated voltage, and that would be 1000 volts. BUT, I'm not 100% sure on that. The ones in the photos below are 6mm in diameter. Someone else on the form may be able to interpret it, OR you could contact Clive Tobin and ask him.

 

The capacitors are connected to the 2 brushes on the motor, then to ground. One capacitor per brush. They are there to reduce the electrical 'noise' given off due to the DC motor's commutators constantly making and breaking the circuit as they spin. If you viewed it while the motor was running, you would see small "sparks". This switching creates small electrical arcs which generate wideband RF. This puts "spikes" or "noise" in the otherwise clean DC current. This noise now entered in the current must have wreaked havoc on the electronics in Clive's terrific TXM-22 Crystal Motor, a brushless DC motor. Again, these capacitors suppress that noise so it doesn't interfere with the motor's electronics.

 

I don't have a parts list for the torque motor or an electrical schematic for the wiring. Maybe Tim Carroll does, OR you could contact Mr. Tobin.

 

The other thing you can do is, open the converted motor you have and copy what Mr.Tobin did.

 

To do that, remove the 2 Lock Rings using external snap-ring pliers.

 

Don't remove the large gear above the motor, that's the clutch. It's most like adjusted correctly now, but you may have to adjust it once you adapt the motor for 12 volts, or maybe you won't. Before you adjust it, make sure you have a full 400ft dummy load to run through the camera. Again, Tim Carroll may have some info or suggestions on adjusting it.

 

Hey Tim, can you tell which direction the gears are set for? Forward or Reverse? LOL.

 

Here's a close up of the electrical bits.

That's about all I can add on this subject. Anyone else have any suggestions?

 

Damn Charlie, is all your equipment in that pristine of shape? That is impressive sir.

 

Best,

-Tim

Hey Tim,

 

I've always handled my camera gear with care, I guess I have a light touch..... or I didn't work much... I can't remember which.

 

Charlie

[flavio filho]

Flavio,

 

The electronic components needed to reduce the 12 volts down to the 8 volts ....

 

Charlie

 

 

Hey Charlie.

 

 

Thanks loads, man! It was AWESOME what you did... Taking the pictures and telling me everything... No words, really.

But the thing is... (and sorry)... Not sure if you meant the opposite (from 8V to 12V???).

 

Please let me know, because actually that's what I want. To change the 8V Motor to 12V...

 

 

Thanks loads, man.

[flavio filho]

 

Please let me know...

 

 

 

Well, that's quite obvious, isn't it? :P I'll open mine, have a look, take pics and post here.

Then we figure out the exact Ceramic disc capacitors and other stuff to buy.

 

Will post the pics soon...

[Tim Carroll]

 

Hey Tim, can you tell which direction the gears are set for? Forward or Reverse? LOL.

 

Well the gears are engaged on the forward driving sprocket, so I would say you have it set for forward. IIRC that right hand drive sprocket in your picture is the one that engages the rear spindle on the Arriflex 16S mag, so that is the take-up spindle when the camera is driven in the forward position. So again, I would say it is set for forward, not reverse.

 

That stuff is really pristine Charlie. I'm impressed.

 

Best,

-Tim

[flavio filho]

Well the gears are engaged on the forward driving sprocket, so I would say you have it set for forward. IIRC that right hand drive sprocket in your picture is the one that engages the rear spindle on the Arriflex 16S mag, so that is the take-up spindle when the camera is driven in the forward position. So again, I would say it is set for forward, not reverse.

 

That stuff is really pristine Charlie. I'm impressed.

 

Best,

-Tim

 

 

Hi again, guys.

 

So, am still stuck on this. Any help?

Need to know what to buy to convert the 8V motors to 12V. Seems quite simple, only soldering the right pieces in there.

Need something to start, please. Every little helps.

 

Thanks,

Flavio

[Simon Jon Knight]

Anyone got an up-to-date schematic of the 12v modification? The close up shows where the two capacitors go but not where the original wire went that is now attached to the resistor..

 

Anyone got any ideas..??

 

Cheers

SK