The number is the width/height of the mounting face in inches. So Nena 17 is 1.7inx1.7in on the mounting face, nema 23 is 2.3inx2.3in etc. though looking at datasheet for different nema sized mount that seems like an approximate not dead on number.
NEMA is just a mechanical aspect and contains zero information about the performance. Equally comparing motors by torque isn't the full picture as the inductance (and other aspects) can be different. Equally important is the stepper-driver & supply voltage.
Oh, that makes sense. I was trying to mentally imagine what kind of FDM printer could possibly need that much power and was very much coming up with a blank, lol.
I see. Size doesn't matter to you. It is all about skills.
Let's me introduce you to the 400W NEMA24 servo.
edit: Sorry. Was only the 400W unit. Somewhere there should be a 750W speciment.
Also be careful with these motor. While a small NEMA17 found on 3D-printer has 0.5 Nm and under normal conditions will stall before serious harm happens this NEMA34 is 9Nm which is enough to break bones.
Those 400W servos are equally dangerous. While only around 1Nm they have roughly 4Nm peak and keep this torque at high RPMs.
Thats why you go CF. It drastically increases the MoE of most plastics and they will not have nearly as much creep; you're pulling mostly against the rigid fibers in the plastic matrix, and not loosely interlinked polymer bonds of plastic alone (which will disconnect over time and causes creep). As long as your service temp is not extremely high (>60C).