Stepping motor characteristics: which statement correctly identifies a core use-case advantage of stepper motors in motion control?

Introduction / Context:
Stepping motors are electromechanical devices that move in fixed angular increments when driven by pulse commands. They are widely used for open-loop positioning where repeatable, discrete moves are more important than continuous high-speed rotation.

Given Data / Assumptions:

• Steppers advance by steps determined by their internal pole/phase geometry.
• Microstepping allows finer positioning granularity.
• They do not require commutators; coils are electronically switched.

Concept / Approach:
The essential advantage is indexed positional control: each drive pulse advances the shaft by a known increment, enabling precise, repeatable positioning without a feedback encoder in many applications. This suits 3D printers, CNC axes (light duty), and pick-and-place systems. Voltage alone does not set speed; step rate (pulse frequency) is the key variable.

Step-by-Step Solution:
Reject voltage-proportional speed; step frequency controls rotor speed.Note the absence of mechanical commutators; control is via electronic commutation.Recognize stepper strengths in indexing; select the option stating discrete positional moves.

Verification / Alternative check:
Drive manuals specify steps/rev (e.g., 200 steps/rev) and microstep ratios that directly translate pulses into position.

Why Other Options Are Wrong:
Option A confuses DC motor behavior; Option B is incorrect technologically; Option C favors AC/BLDC/servo drives for continuous rotation.

Common Pitfalls:
Ignoring torque-speed curves; steppers lose torque at high speeds without appropriate gearing or current control.

Final Answer:
It can index precise positional movements in discrete steps.