I am trying to properly spec a proper stepper motor for a project I am working on. I am attempting to provide roughly 3000 pounds of compressive force (about 13300 Newtons) using a p series NEMA 34 closed loop stepper motor. I believe this is equivalent to lifting about 1,400 kg if the shaft of the motor is 14 mm. This motor has a maximum pull out torque of about 6.5 N-m at roughly 80 rpms... How do I spec a proper motor for my needs? Do I start with power?

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    \$\begingroup\$ You don't have enough information. An (almost) arbitrarily small motor can produce a force over a finite distance given enough gear reduction and time to get there. \$\endgroup\$ – Spehro Pefhany Jan 7 at 21:17
  • \$\begingroup\$ Gearing is all. \$\endgroup\$ – Brian Drummond Jan 7 at 21:24
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    \$\begingroup\$ 80 RPM, is that the desired max speed? \$\endgroup\$ – rdtsc Jan 7 at 21:43
  • \$\begingroup\$ What gearbox are you using to convert rotation (torque), into linear motion (force)? The gearbox efficiency will be very important, as well as the maximum speed you require. A hydraulic jack for example can lift 5000 kg or more, using only a smallish 12v motor. it does this by having a large gear reduction. \$\endgroup\$ – Drew Jan 8 at 2:04
  • \$\begingroup\$ My apologies. I guess I am just lost on where to start so I can properly spec a motor. The most important requirement is that I need the motor/gearbox to be able to supply 3000 lbs of linear force to an area. I plan to achieve this using a rack that is actuated by the motor, whether directly or using a gear configuration. I only need the 3000 lbs of linear force to act in the direction of the rack for about 0.25 in/s for about 2 seconds. Hopefully this clears up my problem statement. Any guidance on how to spec a motor as well as how a gear train/box would benefit my needs. \$\endgroup\$ – MistakesWereMade Jan 8 at 17:23

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