I need help on motor sizing

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1

Hi,

I’m working on calculating the motor sizing for the projects, but I’m not sure I’m right or wrong.

Motion - rotate 90 degree

RPM = 2
t = 7.5 sec
Gear reduction = 4
Jload for the system = 0.0488 kg-m^2
Tf = 2.9456 Nm
Tg = 0 Nm
Ta = 0.00273 Nm
Tpeak = 2.945 Nm

So, I picked a HT17-275.
Jmotor = 0.000008191 kg-m^2 (given by manufacturer)
Ta.m = (Jmotor+Jload)(2pi)(rps/(t/2)) = 0.00273 Nm
Tpeak = Ta.m+Tf = 2.95 Nm

Gearhead GBPS-0401-CS-004
Rated Output Toruqe = 89 in-lbs = 10.05565Nm

Torque margin
(2.95 + 10.05565 + 2.945) / (2.95) = 340%

Can anyone help me with motor sizing?

Attached is the sketch of motion.

Thank you in advance.

Sketch of Motion
Sketch of Motion1280×961 227 KB

2

@tay0237 Welcome to the RobotShop Community.

Applied Motion’s NEMA 17 HT17-275 seems like a pretty good motor, capable of providing up to 3.3Kg-cm at low speeds (24V). Coupled with Anaheim Automation’s GBPS-040X-CS 4:1 NEMA-17 compatible planetary gearbox, you could get 13.2Kg-cm out. Unless I’m missing something, that’s far from the 480Kg-cm you have as the “Rate Output Torque” above though.

Note that Applied Motion provides the torque-speed curves for their stepper motors: