Design equations for the tooth distribution of stepping motors

Two design equations for stepping motors are developed in terms of number of phases, number of poles per phase, number of stator teeth per pole, number of steps per revolution, step angle, tooth pitch of the rotor, and tooth pitch of the stator. Two tooth distribution configurations are considered. In one type of motor, the tooth pitch of the rotor is not equal to the tooth pitch of the stator. In the second type, the two pitch angles are equal, but there is a pole-to-pole offset in the stator tooth distribution to generate the necessary driving torque. A typical use of the design equations is illustrated using numerical examples. The design equations can be used in the evaluation of existing motors and in the design of new motors