Hello,
I need to build a pulley that will raise and lower about 40lbs and need accurate positioning. Since there will be a resting load weight, I decided to go with a stepper motor as opposed to AC induction motor with VFD and dc bake injection.
I am wondering what size Stepper I need and if you can also suggest the best drive as well. the drive will not be programmed to start and stop stop set points. Instead, I need a hand control to forward/reverse and start/stop.
Thanks in advance
You indicate the load will be raised (assuming against gravity). Since torque equals distance between the axis of rotation and in this case the radius of the pulley multiplied by the force being lifted, we would need to know which pulley you are considering before suggesting an appropriate stepper motor with sufficient torque. As you can see, the smaller the radius, the lower the torque, but you’ll also have a slower moving system because linear speed (i.e. lifting speed) equals angular velocity (w) multiplied by radius. We would also need to know the lifting speed.
T=Fr
v=wr
There are not many stepper motor controllers which have manual / user input. The choice of stepper driver depends on the type of stepper motor , the voltage at which you want it to operate, and the maximum current.
Hello,
Thanks and sorry for delayed reply.
What about a gear motor? 12V with a RPM of 10 or 20. I need something that can lift about 20lbs ( I am using pulleys to lower weight) and hold it if stopped.
Thanks for any ideas.
A DCG gear motor is certainly a good option, but in order to get accurate positioning, you’d need an encoder at the rear. Note too that an encoder offers relative as opposed to absolute positioning (i.e. when you power it up, it doesn’t know its position and you would need to treat that as “zero” unless you add other sensors. You would need a microcontroller, motor controller and there would be programming required.
