Microstepping

Microstep drivers divide the basic step angle of the motor by decreasing the current to one phase while increasing the current to the next phase in increments. This results in the motor taking smaller steps. With a microstep driver the motor’s basic step can be divided into smaller steps ranging from 1/1 to 1/250.

The illustrations to the right represent the basic concept of microstepping.

Figure 1 - phase A is at 100% current so the rotor lines up directly.

Figure 2 - the current to phase A is decreased to 75%, while 25% of the current is now in phase B.

Figure 3 - the current for both phase A and B is 50% so the rotor lines up directly in the middle of the two.

Figure 4 - phase A is now at 25% and phase B is at 75% so the rotor moves closer to phase B.

Figure 5 - phase A is turned off and phase B is at 100% so the rotor finally lines up directly with phase B.

By microstepping the motor in this example we have divided the basic 500 steps per revolution of the 5-phase motor by 5, increasing it to 2,500 steps per revolution. The resolution of the motor is now 0.144°.

Microstepping not only provides a higher resolution, it also ensures smoother operation, lower vibration and less noise than other drives.

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