Some performance differences between stepper servo systems and their respective motor designs. Stepper motors have more electrodes than servo motors. One rotation of the stepper motor requires more current exchange through the winding than the servo motor. Compared to servo systems, stepper motors are designed to reduce the speed at higher speeds. Using a higher drive bus voltage reduces this effect by reducing the electrical time constant of the winding. Conversely, high pole numbers have beneficial effects at lower speeds, making stepper motors a torque advantage over servo motors of the same size.
Another difference is the way each motor type is controlled. Conventional stepper motors operate in open loop constant current mode. This saves money because most positioning applications do not require an encoder. However, stepper systems operating in constant current mode generate a significant amount of heat in the motor and driver, which is a consideration for some applications. Servo control solves this problem by providing only the motor current required to move or hold the load. It also provides peak torque several times higher than the maximum continuous motor torque during acceleration. However, by adding an encoder, it is also possible to control the stepper motor in this full servo closed loop mode.
Stepping is easier to debug and maintain than servos. They are cheaper, especially in small motor stepper motor drive applications. If they operate within design limits, they do not lose steps or require an encoder. The stepper remains stable and remains in position without any fluctuations, especially under dynamic loads.
Servo systems excel at applications that require speeds above 2,000 RPM and high speed and high torque or where high dynamic response is required. Stepper speeds below 2,000 RPM, medium to low acceleration and high holding torque
But with the excellent stepper motor driver, the stepper motor can reach up to 4000RPM.