In the step (1) from the Angle, three-phase motor is better than two phase motor

(2) three-phase motor two phase excitation maximum keep the moment for 3 quality T1 (T1 for single-phase excitation torque), and two phase motor for quality 2 T1, so the synthesis of three-phase motor torque. (3) three-phase motor torque fluctuation ratio two-phase motor to small. (4) three-phase motor continuous 2 steps for half step torque difference than two phase motor will be small. [5] three-phase motor winding can star connection, and three terminal drive, excitation circuit transistor six;
And two phase motor is eight. [6] continuous operation, due to rotary joints three-phase stepper motor structure reason, the flux and current three harmonic is eliminated, so the vibration of the three-phase motor torque than two phase motor will be small. The conclusion is obvious. Another conclusion is HB motor is more suitable for low speed high torque purpose; RM type suitable for smooth running and speed is more than 1000 r/min purposes; And PM type low cost, in low speed vibration and high speed large torque, three-phase PM motor than two phase motor performance is better. Therefore, the current most development prospect, when is the hybrid stepping motor, and hybrid motor and to the following four direction: One of the development trends, is to continue along the direction of miniaturization. With the motor itself in the field of application of widening and all kinds of the continuous miniaturization, requirements and the related motor must also be more and more small, in 57, 42 frame size motor application after many years, now the base number to 39, 35, 30, 25 direction downward extension. Swiss ESCAP company also recently developed only 10 mm diameter of stepping motor.
The development trend of another, is change circular motor for square motor. Due to the motor using square model structure, make rotor may design better than large, round, so the moment volume ratio will be greatly improved. The same base number of the motor, square moment than round will be raised by 30% ~ 40%. The third development trend, the motor for integrated design. The rotor position sensor, reduction gear, etc and motor noumenon integrated design together, so make it easy to form a closed loop system, thus has better control performance. The development trend of four to rotary union five and three-phase motor direction. It is used widely in two and four phase motor, its vibration and noise is bigger, and five and three-phase motor has the dominance. And these two kinds of motor is concerned, five phase motor drive circuit than three-phase motor complex, so the three-phase motor system of performance to price than five phase motor better.
China's situation is different, until the 1980 s, has been magnetic resistance type stepping motor is dominant, hybrid stepping motor is 80 s began to fiber optic rotary joint development, is still the two kinds of structure type coexist. Although the new hybrid stepping motor completely may replace reluctance motor, but reluctance motor of the machine won the long-term use, for its technology is also more familiar, especially typical hybrid stepping motor's footsteps Angle (0.9 ° and 1.8 °) and the typical reluctance motor step pitch Angle (0.75 ° and 1.5 °), users change the product structure is not very easy, this makes two models of both the situation is in a relatively short period of change. This kind of present situation of stepping motor is adverse to the development of.