What happens when voltage to the stepper motor coils are turned on and off in sequence?

When voltage is applied to the stepper motor coils in a sequential manner, it creates an electromagnetic field that interacts with the rotor. This interaction causes the rotor to align with the energized coils and move incrementally with each change in the activated coils. The precise control of these electrical signals allows for accurate positioning and rotation in small, discrete steps.

Stepper motors are specifically designed to take advantage of this sequential powering method, enabling them to achieve high precision in their movements, which is essential in various applications such as robotics and CNC machinery. Thus, the rotation of the motor is a direct result of the carefully timed switching of the voltage across the coils, making it possible to control the movement smoothly and reliably.