Slowing down a motor.
My press is finally all set up and ready to go except my Kimble single speed motor goes so fast! I understand it is a single speed and I cannot just switch the speed around with a switch, but is there a way to manually go into the motor and change the speed/slow it down? Being a beginner I don’t want to start out with a fast press. I have a 8x12 Chandler and Price by the way. Please help because I am ready to print!
Hi There,
You’d need to gear it down by running the motor via pulleys to slow it down. You can buy stepped pulleys that incrementally slow down a motor. It sounds like you are trying to drive the press directly from the motor.
You could get a slower motor or run through a gearbox.
A lot of presses here in the UK I’ve moved have had all manner of home made pulleys and belts to slow them down.
You could get a PWM (Pulse Width Modulator) to actually slow the motor down but this will probably remove too much torque.
There must be a machine shop near you or go online for other solutions. Good luck or alternatively get a treadle…!
you could get a 3 phase motor with a VFD. This will give you a range of control for RPMs with a dial to control speed.
Go with a treadle if you have the crank flywheel shaft. Much slower and safer for a beginner. If not then the stepped pulleys is the way to go. A very small one on motor and a very large one on the press. If you use the flywheel itself as the large pulley that works fairly well, though it adds its own set of challenges. For instance it is harder to mount a brake if the flywheel has a belt looped around it.
Learned friends are hinting at the solution but not quite going far enough. Follows:- small litho machines, Multiliths, Gesteliths Hamadas, and many more, up to Heidelberg Platens and beyond are driven with fixed speed motors running at optimum torque and power, speed governed mechanically with an almost simple, coned pulley attached to the output shaft of the motor, describing a small arc around the shaft the motor is mounted on, and controlled by a lead screw at front of machine. Not exactly high tech and working perfectly on applications as diverse as Tiny lithos, Adana T.P. 48,s Thompson Platens, Heidelberg Platens, etc etc (and the principle holds good for single phase or three phase, which is usually more complex and generally more expensive especially if artificial inverters are involved).The internet appears to be well blessed for purchasing such units, should second hand not be an option, and the prowess required, would seem to be, within first year engineering student capabilities. Re the tiny pulley on the motor and the flywheel as the big pulley, is usually unsuccessful, as the tiny pulley has so little wrap around that one would be forever using rosin or belt stick to maintain grip at the tiny pulley, or wear it out, so an alternative would be to fit a more suitable size big pulley, as an outrigger to the flywheel but only one fixed speed would be available unless a small array of slightly differing size slave pulleys were available to quick change on the motor shaft. No brake problem!!!