servo motor, step motor karşılaştırması (en)


Stepper Vs. Servo Motors
CharacteristicsServo Motor (DC BrushedStepper (Hybrid)
CostThe cost for a servo motor and servo motor system is higher than that of a stepper motor system with equal power rating.This feature would have to go to stepper motors. Steppers are generally cheaper than servo motors that have the same power rating.
VersatilityServo motors are very versatile in their use for automation and CNC applications.Stepper motors are also very versatile in their use for automation and CNC applications. Because of their simplicity stepper motors may be found on anything from printers to clocks.
ReliabilityThis is a toss up because it depends on the environment and how well the motor is protected.The stepper takes this category only because it does not require an encoder which may fail.
Frame SizesServo motors are availible in a wide variety of frame sizes, from small to large motors capable of running huge machines. Many of the motors come in NEMA standard sized.Stepper motors do not have as many size selections as servo motors in the large sizes. However stepper motors may still be found in a variety of NEMA frame sizes.
Setup ComplexityServo motors require tuning of the (PID) closed loop variable circuit to obtain correct motor function.Stepper motors are almost plug-and-play. They require only the motor wires to be wired to the stepper motor driver.
Motor LifeThe brushes on servo motors must be replaced every 2000 hours of operation. Also encoders may need replacing.The bearing on stepper motors are the only wearing parts. That gives stepper motors a slight edge on life.
Low Speed High TorqueServo motors will do fine with low speed applications given low friction and the correct gear ratioStepper motors provide most torque at low speed (RPM).
High speed High TorqueServo motors maintain their rated torque to about 90% of their no load RPM.Stepper motors lose up to 80% of their maximum torque at 90% of their maximum RPM.
RepeatabilityServo motors can have very good repeatability if setup correctly. The encoder quality can also play into repeatability.Because of the way stepper motors are constructed and operate they have very good repeatability with little or no tuning required.
Overload SafetyServo motors may malfunction if overloaded mechanically.Stepper motors are unlikely to be damages by mechanical overload.
Power to Weight/Size ratioServo motors have an excellent power to weight ratio given their efficiency.Stepper motors are less efficient than servo motors which usually means a smaller power to weight/size ratio.
EfficiencyServo motors are very efficient. Yielding 80-90% efficiency given light loads.Stepper motors consume a lot of power given their output, much of which is converted to heat. Stepper motors are usually about 70% efficient but this has some to do with the stepper driver.
Flexibility in motor resolutionSince the encoder on a servo motor determines the motor resolution servos have a wide range of resolutions available.Stepper motors usually have 1.8 or 0.9 degree resolution. However thanks to micro-stepping steppers can obtain higher resolutions. This is up to the driver and not the motor.
Torque to Inertia RatioServo motors are very capable of accelerating loads.Stepper motors are also capable of accelerating loads but not as well as servo motors. Stepper motors may stall and skip steps if the motor is not powerful enough.
Least Heat productionSince the current draw of a servo motor is proportional to the load applied, heat production is very low.Stepper motors draw excess current regardless of load. The excess power is dissipated as heat.
Reserve Power and TorqueA servo motor can supply about 200% of the continuous power for short periods.Stepper motors do not have reserve power. However stepper motors can brake very well.
NoiseServo motors produce very little noise.Stepper motors produce a slight hum due to the control process. However a high quality driver will decrease the noise level.
Resonance and VibrationServo motors do not vibrate or have resonance issues.Stepper motors vibrate slightly and have some resonance issues because of how the stepper motor operates.
AvailabilityServo motors are not as readily available to the masses as are stepper motors.Stepper motors are far easier to find than quality servo motors.
Motor SimplicityServo motors are more mechanically complex due to their internal parts and the external encoders.Stepper motors are very simple in design with no designed consumable parts.
Direct Drive CapabilityServo motors usually require more gearing ratios due to their high RPM. It is very rare to see a direct drive servo motor setup.Stepper motors will work fine in direct drive mode. Many people simple use a motor couple and attach the motor shaft directly to the leadscrew or ballscrew.
Power RangeBecause servo motors are available in DC and AC servo motors have a very wide power availability range.The power availability range for stepper motors is not that of servo motors.
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