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Two Difference Of The Servo Motor And Stepper Motor
- May 28, 2018 -

First, different control precision

Two-phase hybrid stepper motor step Angle is 1.8 ° and 0.9 °, 5 phase hybrid stepping motors interval Angle is 0.72 ° and 0.36 ° in general. There are also some high-performance step motor by subdividing hind leg from the Angle of smaller. Such as SANYO (SANYO DENKI) production of two-phase hybrid stepper motor where the step Angle can dial the code switch is set to 1.8 ° and 0.9 ° and 0.72 ° and 0.36 ° and 0.18 ° and 0.09 ° and 0.072 ° and 0.036 °, combine the two and five phase hybrid stepper motor step Angle.

Control precision of the ac servo motor by the motor shaft after the rotary encoder. Sanyo all-digital ac servo motor, for example, in line with standard 2000 encoder of the motor, drive due to the internal used four frequency multiplication technology, the pulse equivalent to 360 ° / 8000 = 0.045 °. For with 17 encoder of the motor, drive round each receive 131072 pulse motor, i.e. the pulse equivalent of 360 ° / 131072 = 0.0027466 °, is a step from the Angle of 1.8 ° of the stepper motor of 1/655 of the pulse equivalent.


Second, the low frequency characteristics are different

Stepper motor at low speed is easy to appear low frequency vibration phenomenon. Vibration frequency is associated with load and drive performance, it is generally believed half frequency vibration frequency for the motor no-load takeoff. This determined by the working principle of stepper motor in low frequency vibration phenomenon is very bad for the normal operation of the machine. When the stepper motor work in low speed, general damping technology should be adopted to overcome the low frequency vibration phenomenon, such as add damper on motor, or drive the segmentation technology, etc.

Ac servo motor running smoothly, even in the low speed also won't appear when the vibration phenomenon. Ac servo system has a resonance suppression function, can cover the mechanical rigidity, and internal system has the function of frequency resolution (FFT), can detect the mechanical resonance point, is advantageous for the system adjustment.