Arri 2 motors and power supply

November 17, 2005

I have a constant speed motor 24/25 frames for the Arriflex 2 and have never been able to find the correct power supply to give the required voltage and ampage to power it .. According to the manual and the people at visual products.com, this constant speed motor should run at approx 17 volts at 4 amps. Unable to find an original power supply for the motor, I tried using a power supply from my laptop which has the same output, but when running the camera with the 400ft mag loaded with film, the camera only runs at approx 20 fps. I have also tried a variable voltage contol unit and taken the voltage up as high as 24 volts at 6 amps but still the motor is still running at less than the requred FPS. Is it possible the motor is damaged or is it I have an uncommon motor that requires a higher wattage, voltage or ampage??? :unsure:

Edited November 17, 2005 by C.D. Melville

Stephen Williams · November 17, 2005

I have a constant speed motor 24/25 frames for the Arriflex 2 and have never been able to find the correct power supply to give the required voltage and ampage to power it .. According to the manual and the people at visual products.com, this constant speed motor should run at approx 17 volts at 4 amps. Unable to find an original power supply for the motor, I tried using a power supply from my laptop which has the same output, but when running the camera with the 400ft mag loaded with film, the camera only runs at approx 20 fps. I have also tried a variable voltage contol unit and taken the voltage up as high as 24 volts at 6 amps but still the motor is still running at less than the requred FPS. Is it possible the motor is damaged or is it I have an uncommon motor that requires a higher wattage, voltage or ampage??? :unsure:

Hi,

How are you checking the speed your camera is doing? When did you last lubricate the camera?

Stephen

andrewbuchanan · November 17, 2005

My constant motor has an 18V 4amp (I think, it isn't in front of me) battery, for the constant 24fps motor and a VS motor. I've never heard of anything higher than 24V for the IIc motors (including the CE base which goes up to 80FPS). So I don't think it is a power supply issue. I would also consider the following:

Is your tach out of adjustment? Are you getting 24fps and the tach is slow? Check the camera's speed with no mag or you may need a frame speed tester from the nearest shop. Also, try your motor on another IIc if you can find one.

Is you mag causing a torque problem for the motor? Try running with 400' in the mag but not threaded through the camera body (leave it taped-up or place it on the feed roller backwards so it doesn't come off the roll). Can the motor push this load at 24fps? If so, it might be a threading or lub issue.

Finally, as Stephen mentioned, lubrication is very important and the easiest problem to fix. I would begin there. I wouldn't think that the voltage/amp issue would be the cause of the problem though.

November 18, 2005

My constant motor has an 18V 4amp (I think, it isn't in front of me) battery, for the constant 24fps motor and a VS motor. I've never heard of anything higher than 24V for the IIc motors (including the CE base which goes up to 80FPS). So I don't think it is a power supply issue. I would also consider the following:

Is your tach out of adjustment? Are you getting 24fps and the tach is slow? Check the camera's speed with no mag or you may need a frame speed tester from the nearest shop. Also, try your motor on another IIc if you can find one.

Is you mag causing a torque problem for the motor? Try running with 400' in the mag but not threaded through the camera body (leave it taped-up or place it on the feed roller backwards so it doesn't come off the roll). Can the motor push this load at 24fps? If so, it might be a threading or lub issue.

Finally, as Stephen mentioned, lubrication is very important and the easiest problem to fix. I would begin there. I wouldn't think that the voltage/amp issue would be the cause of the problem though.

Yes,Thanks for that!. So. I tried running the camera without the magazine and it runs at 24/25 fps nicely but as soon as I place the magazine back on it drops down to approx 20 fps. (I have three magazins and it happens all the same) It drops even more when film is through the gate as though the motor is week. The camera works niclely with the variable speed motor at the same voltage input, although I do have to increase voltage a little more than avearage the get the required fps.. Does your constant speed motor run at the same speed without the magazine as it does on?..There are not many places here that can check this motor out without just replacing it!

Edited November 18, 2005 by C.D. Melville

Rolfe Klement · November 18, 2005

it might be a problem where the motor connects to the gear that sits by the magazine transport. It is quite easy to open the side of the camera (opposite to the door) and have a quick look if there are any issues

thanks

Rolfe

Stephen Williams · November 18, 2005

it might be a problem where the motor connects to the gear that sits by the magazine transport. It is quite easy to open the side of the camera (opposite to the door) and have a quick look if there are any issues

thanks

Rolfe

Hi,

Thats one of the nice things with old film cameras, It's possible to open them up and carry out some repairs. Every time i've taken a nold camcorder to pieces, thats the end of the game!

Stephen

Clive Tobin · November 19, 2005

... runs at 24/25 fps nicely but as soon as I place the magazine back on it drops down to approx 20 fps...

I don't know if this motor version has the transistor amplified governor contact or not, but I would suspect burned contacts in the governor, worn-out governor slip rings, or an open transistor. This is probably a 16.8 volt motor. Sorry but I don't repair these, but I used to rip them apart and convert to crystal.

Jizhong Zhang · March 8, 2007

I saw a 80fps II c too but how to Change the motor speed?? and why the power supply adapter has three wires? and one can show me me how to connect? and I also want to know how many volt of the II c `s power supply? 12v? 24??

Tim Carroll · September 14, 2007

I also want to know how many volt of the II c `s power supply? 12v? 24??

I've run my Arriflex 35-2C constant speed (24fps) motor on 12 volts and on 16 volts, and the speed (checked with a strobe) remains the same. I think the 24fps constant speed motors are designed to work with either 12 volts or 16 volts. I would not run 24 volts through them though.

-Tim

John Sprung · September 14, 2007

In the old days, it was always 8.4 Volts for the 16mm Arri's, and 16.8 Volts for the 35-II's. Eclairs were 12 Volt, and used the same 4 pin XLR's that are still in use today.

-- J.S.