oyostepper

Hybrid stepper motors are often classified by the number of phases in the stator, with the majority of hybrid steppers having either 2 phases or 5 phases.A 2-phase stepper motor typically has eight poles, or four poles (two pole pairs) per phase. When the stator phases are energized, the rotor moves one-quarter of a tooth pitch to align with the energized stator poles. Since the rotor has 50 teeth and moves ¼ tooth pitch at a time, the motor makes 200 steps per revolution, giving a basic step angle of 1.8 degrees.Step angle = 360 ÷ (2 * # stator phases * # rotor pole pairs)Step angle = 360 ÷ (2 * 2 * 50) = 1.8 degreesstator phasesThis 2-phase stepper has eight poles. One phase is made up of the odd-numbered poles (1, 3, 5, and 7), and the other phase is made up of the even-numbered poles (2, 4, 6, and 8). The front rotor cup has 50 teeth, and the back rotor cup (not shown) also has 50 teeth, offset from the front cup by 1/2 tooth pitch.Image credit: PhidgetsA 5-phase stepper motor has ten poles, or two poles (one pole pair) per phase. In this configuration, the rotor only needs to move one-tenth of a tooth pitch to line up with the energized stator poles. With 50 rotor teeth moving 1/10 tooth pitch with each step, the 5-phase motor makes 500 steps per revolution, resulting in a basic step angle of 0.72 degrees.Step angle = 360 ÷ (2 * 5 * 50) = 0.72 degreesstator phasesComparison of a 2-phase stepper motor with 8 poles (left) and a 5-phase stepper motor with 10 poles (right).Image credit: Oriental Motor USA Corp.The smaller step angle of a 5-phase stepper motor provides higher resolution than the 2-phase design, and microstepping control can produce even greater resolution. (Note that the accuracy of movement is determined by the motor’s mechanical accuracy, which depends on the quality of the components used in the motor construction and on the methods used for manufacturing and assembly.)Although higher resolution is an inherent benefit of stepper motors with more stator phases, the primary reason for using a higher-phase motor (5-phase versus 2-phase, for example) is that more phases, and therefore smaller steps, produce less torque ripple and more usable torque. Another benefit of more stator phases and a smaller step angle is that the motor is less likely to miss steps due to undershooting or overshooting, making it more reliable in open loop operation.[https://www.oyostepper.com/category-1-b0-Hybrid-Stepper-Motor.html][https://www.oyostepper.com/category-30-b0-Closed-Loop-Stepper-Motors.html]