In motor control for automation, which statements about stepping (stepper) motors are generally true regarding motion, indexing, direction, and construction?

Introduction / Context:
Stepper motors convert digital pulse commands into discrete angular movements. Their predictability and open-loop positioning make them popular in printers, CNC stages, and pick-and-place machines. Understanding core attributes—speed variability, step size, bidirectional motion, and brushless construction—helps in selecting and driving these motors effectively.

Given Data / Assumptions:

• We consider mainstream permanent-magnet and hybrid stepper types.
• Drive electronics can vary pulse rates to change speed.
• Poles and windings determine basic step size (e.g., 1.8 degrees).

Concept / Approach:
Steppers advance one step per input pulse. Varying the pulse frequency varies speed; microstepping further refines motion. Pole count and mechanical design set the native step angle. Drive sequences can reverse the step order to rotate in either direction. Because steppers are brushless, they do not use mechanical commutators; instead, electronic commutation energizes phases in sequence.

Step-by-Step Solution:

Verification / Alternative check:
Application notes for stepper drivers explicitly describe speed control by pulse rate and bidirectional sequences, with no mechanical commutation involved.

Why Other Options Are Wrong:

Common Pitfalls:
Attempting high speeds without acceleration profiles, leading to missed steps; overlooking torque drop at higher step rates.

Final Answer:
All of the above.