Construction of Stepper Motor

A stepper motor consists of a permanent magnet sandwiched between the two rotor halves (causing axial polarity), which make up the spinning part of the motor, placed into a stator housing where the stator coils of wire make up the different motor phases. With a 2 phase stepper motor, each phase has four coils.

The phase is magnetized where the A and A- phases (or B and B-)are magnetized at the same time so that both A phases are magnetized as one pole, and both A- phases are magnetized as the opposite pole because the winding direction of the A-phase is opposite the winding direction of the A- phase.

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Stepper Motor Construction

Stepper Motor Construction

The rotor is connected to the motor shaft, which gives the output rotation and torque of the motor when voltage and current pulses are applied to the motor windings. The bearings on either side of the rotor allow for smooth rotation with little friction and wear.

The bearings are placed into their designated spaces in the front and rear end caps, which allow for the concentricity of the rotor inside the stator. Perfect alignment of the rotor and the stator is very important because the air gap between them, where the motor torque is generated, must be equal on all sides and is only a few nanometers wide – thinner than a strand of hair. If you’re having trouble narrowing down your exact requirements, let us help.