It is easy to found stepper motors with torque over 2NM for a few coins, however, only expensive industrial servomotors achieve this torque.
- Stepper motor: 10usd for 1.3nm with 2.8V at 3.5A rpm 0.6kg
- Servo AC motor: 278usd for 2.39nm with 220V~ at 3A 3000rpm 6kg
- Servo DC motor: 67usd for about 0.4nm 24V at 7.8A 3000rpm 1Kg
Torque is not power, and closed loop has many benefits, but I am still confused:I believe many industrial purpose require quite high torque (CNCs, robotic, etc.) and it would be preferable (to my understanding) a lower rpm with higher torque. Additionally, it seem to me that any purpose for a servomotor require more than a few 0.4nm
Why is this torque that different?
What is the benefit / purpose of those non-hybrid servo-motors?
What am I missing?