I just picked up an extra rheostat 6 volt motor for my Konvas KSR-1m It's in fairly rough shape so i was considering having it rebuilt but then I started thinking, why not see if it's possible to rehouse a 12 volt, crystal sync motor in the framework.
Konvas-1 camera ( KSR-1, KSR-1M ) created a many years ago and motor building industry do not had a many types of DC motor for drive of camera.
The other questions - the version of speed control of camera drive.
And this must be trusted device.
The designer of Konvas build of 25M-8M drive.
25M-8M drive included of DC motor with stator and rotor windings.
This type of DC motor can control of speed of rotation of axis by control of current of stator or rotor windings. And designer choose of current type of speed control by rheostat with hand control.
The camera ask of high torsion torque and ask of high power of DC motor (25..30W ).
From other side, we do not have many types of compact accumulators at time of building of Konvas-1 camera and designers choose of battery from 5 pcs of silver-zinc cell SC-25, 25ah.
25M-8M drive ask of 8 v or 6 v power source and have two version of winding and rheostat connections.
About technical peculiarity.
Konvas-1 had multi type of drive and had :
- mechanical, spring drive,
- single shooting crank drive,
- normal speed crank drive,
- electrical motor drive.
That's why, the desin of mechanism of camera have additional reducer for hand crank rotation with normal speed shooting, have special stopping mechnaism for spring drive.
If it were possible to remove the 6 volt motor from the assembly and replace it with a 12 volt crystal sync motor, it would solve any possible tork and pulling issues while still keeping the single frame animation and hand cranked capabilities that I so dearly love about this cool little camera.
If we compare of next version of Konvas cameras ( Konvas-1M, 2M ) and next generation of Konvas motors ( 15EPSS, 17EP-16 APK... ) we can see, Konvas-1 camera have other type of connection of axis of mechanism with axis of reducer of motor and other type of motor mount.
Yes, of course, If you create of special part for connect of 12 v motors with axis of Konvas-1 camera and part of body of reducer with view of Konvas-1 motor mount, you can attach of 12 v motor with Konvas-1 camera.
But, this can be complex project of upgrade.
From other side, the plastic mirror disks of Konvas-1 camera rare now and you can have problem at searching of spare shutter disks.
Konvas-1 do not have a possiblity of adjust of position of shutter disk, because, this procedure do at factory only and do not adjust at time of use of camera.
Konvas-1 mechanism have ball bearings and have more high value of noise from Konvas 1M,2M mechanisms with friction bearings.
After you study of all trhis ideas more detailed, you can think, you need upgrade of 12 v motors for Konvas-1 or can be better If you take of Konvas-1M, 2M body ?
As my opinion, the DC motors with stator and rotor windings ask of current control and do not compatible with modern pulse-width modulation of proportional, integral, derivative speed control.
I hear about a few projects of analog systems of speed stabilization of 25M-8M motors.
This was systems without feed back and hand manual adjust of speed only.
This was like electronic rheostat speed setting.
This systems build on old high power germanium transistor, ask of high power radiator and lost a some part of power of battery.
I will be glad, to discuss of any opinion about building of speed control systems of 25M-8M drive.
The great result at modern pulse-width modulation of proportional, integral, derivative speed control had DC motors with permanent magnet and hollow armature ( without magnetic circuit of rotor ).
This is type of DC motor ( like of russian DPR motos ) have very small inertia of rotor, have less self-induction.
The camera cog is made of either fiber or some kind of plastic and the drive cogs have a sloped side that allow a notched side to slide into place but allow the animation hand crank to be turned backwards without engaging the camera mechanism. The newer stabilized and sync 1Ms use an slotted notch with corresponding cog and were not designed to use the hand crank. I can't help but wonder if the sloped cog of the KSR-1 is inherently less stable and far less suited to crystal sync than the slotted solid cog of the 1m.
Yes, This is true.
The Konvas-1M, 2M version of conenction of axis of mechnaism with axis of motor ( slotted notch with ribber tubes) have more stable connection. And this very important for any automatic system of speed stabilization.
Because, the motor have two side of control : to increase of speed and braking.
The the sloped cog of connection of mechanism and motor of Konvas-1 have one side toothing only and can increase of speed only.
At mode of breaking the sloped cog will turning without cohesion.
The sloped cog work like one side free-wheel clutch.
The only problem I can see is I want it to shoot with 400 ft mags in anamorphic to make it practical to use as the B camera on my productions. A crystal sync and barney would allow me to use it in conjunction with the Kinor on a 2 camera shoot if it were set back far enough out side. I would love to have the option of a wild motor and a sync motor. If a 12 vt conversion is impractical or even impossible, can a 6 vt rheostat motor be converted to crystal sync even if it's 24-25 FPS only?
About 400 ft magazines.
If you have Moskinap made version of Konvas-1 camera, 400 ft magazines of Konvas-1M, 2M cameras must be full comatible with your camera.
If you have KMZ made Konvas-1, sorry, this do not compatible and 400 ft magaziones super rare.
About upgrade of Konvas-1 on crystal sync speed, we can have two version:
- upgrade of axis of mechanism, motor mount for attach of crystal sync speeds motor of Konvas 1M, 2M cameras
- upgrade of mechanical speed stabilizator device of Konvas-1.
If you install of modern DC motor with feed back on hole of speed stabilizer and install of gear on axis of motor, you can run of mechnaism.
All of this projects of upgrade can be complex.