Quote Originally Posted by wilfy View Post
see there is me misunderstanding the reason behind different sized motors. however when it comes down to running the motors in the right RPM range, is it really a case of buying the right motor if you got it wrong or can you make the wrong motor work for you if you are using belts and pulleys?
Yes you can recover to a point by using belts but something has to be lost in the process.? IE: (These examples assume motors run at correct voltage)
Too small motor regards torque will need to be geared say 2:1 but the screw speed is half'd so machine speeds are lower. Plus the motors are working harder and therefore the drives to achieve the same speed has correct motors would be, this shortens life expectancy.
Supplying Higher voltage to motors will increase rpm's slightly but also create excessive heat and eventually damage the motors.

It's possible to have too large motor.? Large motors like Nema34's run quite bit slower than smaller nema23's and RPM's can be too low for the ideal required machine speeds. Gearing say 1:2 will increase screw speed but torque and resolution is lost. Same applies regards voltage.

The way gearing can work is if you match the screw to the motor.? In this case a lower or to high spec'd motor can be made to work in a way you'd like and still have the speed and resolution you want or happy with. This is done by choosing either a higher or lower pitch screw than other wise would be chosen if the ideal motor/screw combo was available. . . BUT. . Still the same torque/resolution loses/gains applies just now your using them to your advantage.!!

Just know that selecting the right motor/drive/voltage/screw in the first place can't be beaten and gearing to make some short fall up always comes at a price.!!