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Best motor for pulling a string?
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Best motor for pulling a string?

by SusanL on Thu Jun 24, 2021 10:49 am

Hello,

I am looking for some advice on picking a motor.

This is what I want to do:
I have a cable in an electrophysiology setup that needs to be able to move freely, but it also needs to be kept off the ground and out of the way.
I would like to use a motor to gently pull on a string that is attached to a loop in my cable. The string+motor would act sort of like an elastic that keeps some tension on the cable so that the cable end can move freely. Also, the motor should pull the cable upward when the connector at the end gets unplugged (this would mean that there is nothing pulling on the cable anymore).the cable doesn't need to be held up when the power is off (it could be, but this is not a necessity). There will be no enormous forces involved, the maximum theoretical pull on the cable will be about 300g, but I don't need the motor to life this. The motor basically acts as a counterweight.
There will be no enormous forces involved, the maximum theoretical pull on the cable will be about 300g, but I don't need the motor to lift this weight (). The motor basically acts as a counterweight. We used to have a device that did this, but it has sadly disappeared. So, I'm hoping to DIY one.

I think that this means that I need a motor that continuously and gently pulls on the cable, but I am not sure what the best choice of motor is. I've been thinking about using a continuous rotation servo, but a maybe a stepper motor would be a better choice?

P.S: I hope my explanation makes some sense :)

SusanL
 
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Joined: Sat Aug 10, 2013 5:48 pm

Re: Best motor for pulling a string?

by adafruit_support_bill on Thu Jun 24, 2021 3:46 pm

DC motors in general tend to overheat when stalled. And they don't have a lot of toque when stalled either. So a stepper would probably be a better choice.

With a stepper, you can adjust the torque with the supply voltage, PWM and/or the diameter of the take-up spool. How much cable length in total will the device need to accommodate?

adafruit_support_bill
 
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