The step motor and the servo motor are big
Torque-speed characteristics different ac servo motor as the constant torque output, namely in the rated speed (generally is 2000 RPM and 3000 RPM) of less than, can output rated torque and constant power output above the rated speed of stepper motor's output torque increases with speed decreases, and at a high speed when they fell sharply, so its maximum working speed is in commonly 300 ~ 600 RPM The overload ability of different ac servo motor has the capability of overload and torque overload. Its maximum torque for two to three times the rated torque, can be used to overcome inertia load at startup moments of inertia moment of stepper motor is generally not have overload ability, in order to overcome the inertia moment when selection, often need to select a larger torque of the motor, and the machine during the normal work and don't need that big torque, there is a moment of waste phenomenon
They say so much is crap, look at the parameters, torque. In addition, the step motor usually has no big power motor, servo has. Heavy load or servo.
You will find that if is with torque motor servo motor much larger force, reason is that the servo motor drive has the function of adjust output can make servo motor in 2-3 times within a certain time under overload, therefore, when servo motor overload showed a trend of slow down automatically adjust the output current and voltage, make its operating force to keep the original speed slow, locked-rotor occur without (but not limited to motor overload capacity and drive affordable oh). The stepper motor was not the function, but also can meet the state of relatively low frequency (low speed) reach the rated torque output, when high speed stepping electric opportunity because of the high frequency, the pulse current in coil electricity shorter time and reach the maximum current, instead to cause a decline in moment, therefore, the stepper motor is only suitable for low speed and torque is small. Obviously, compared to the stepping motor and servo motor, the servo motor is larger than the step motor
Running performance different ac servo drive system for closed-loop control, the drive can be directly to the motor encoder feedback signal sampling, internal position loop and speed loop, general won't appear step motor lose step or overshoot phenomenon, more reliable control performance Stepper motor control for the open loop control, start frequency is too high or too much load step easy appear lost or blocked, stops frequently occur high speed overshoot phenomenon, so as to ensure the control accuracy, should handle the ascending and descending speed problem Speed response performance better acceleration performance of the ac servo system, different from the static accelerated to the rated speed 3000 RPM it takes only a few milliseconds, can be used for quick start-stop control occasions Stepper motor accelerate from 0 to work speed (generally for a few hundred revolutions per minute) 200 ~ 200 milliseconds
Servo motor stepper motor Different control precision Ac servo motor control precision is interval Angle is 1.8 ° of the stepper motor pulse equivalent 1/655 of 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 stepper motors that are smaller by segmenting the back step The low frequency characteristics of the ac servo motor are very stable, and even at low speeds there is no vibration. 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 to adjust stepper motor at low speed is easy to appear low frequency vibration phenomenon. The vibration frequency is related to the load condition and drive performance, and the frequency of vibration is generally considered to be half the frequency of the motor. The low-frequency vibrations, determined by the principle of stepping motor, are 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
