Servo Motor

Stepper technology has come a long way and certainly can be a good choice for many applications. However, there are considerations such as torque ripple and the fact they will slip position when over torqued. Some systems can detect the slip (even without an encoder) which is good, but unlike a servo will not create and correct the following error. If you add an encoder then more is possible but the control is still open loop, but you then have the ability to know if it slipped and how much. ...

For someone who works with machines that are for large, heavy-duty industrial processes (like steel mills), the answer will be different than if they come from a background of moderate process requirements (pumps and fans) or precision processes (servo motors, actuators, etc).

From my perspective (which is the "large industrial" side of things): I work with designs that have continuous torque ratings that start at about 4500 lb.ft (6.1 x 10^3 N.m) and go up from there. The largest ...

Most manufacturers have separate product families for "servo drives" and "variable frequency drive" or "inverter". However, if we take one of the many VFDs that support PM motors with sensor and a PM servo drive, the control, is the same up to the speed loop. Both servo and VFD (except for DTC) need an inner vector current control loop, which means torque control, and a speed control regulator. They also need a self-tuning pr ...