When designing equipment using motors, it is of course necessary to select the motor most suitable for the required work. This paper will compare the characteristics, performance and characteristics of brush motor, stepper motor and brushless motor, hoping to be a reference for everyone when choosing motors. However, since there are many specifications in the same category of motors, please use them for reference only. Finally, it is necessary to confirm the detailed information through the technical specifications of each motor.
Features of small motor: The following table summarizes the features of stepping motor, brush motor and brushless motor.
| Stepper motor | Brushed motor | Brushless motor | |
| Rotation method | The drive circuit is used to determine the order of each phase (including two phases, three phases and five phases) of the armature winding. | The armature current is switched through the sliding contact rectifier mechanism of the brush and the commutator. | Brushless is realized by replacing brush and commutator with magnetic pole position sensor and semiconductor switch. |
| drive circuit | need | unwanted | need |
| torque | The torque is relatively large. (especially torque at low speed) | The starting torque is large, and the torque is proportional to the armature current. (The torque is relatively large at medium to high speed) | |
| Rotation speed | The torque is relatively large. (especially torque at low speed) | It is proportional to the voltage applied to the armature. The speed decreases with the increase of load torque | |
| High speed rotation | It is proportional to the input pulse frequency. Out of step area in low speed range，It is difficult to rotate at high speed (it needs to slow down) | Due to the limitation of the rectifier mechanism of the brush and commutator, the maximum speed can reach several thousand rpm | Up to thousands to tens of thousands of rpm |
| Rotating life | It is determined by bearing life. Tens of thousands of hours | Limited by brush and commutator wear. Hundreds to thousands of hours | It is determined by bearing life. Tens of thousands to hundreds of thousands of hours |
| Forward and reverse rotation methods | It is necessary to change the sequence of excitation phases of the drive circuit | Reverse the polarity of the pin voltage | It is necessary to change the sequence of excitation phases of the drive circuit |
| controllability | Open loop control of rotation speed and position (rotation amount) determined by command pulse can be carried out (but there is a problem of out of step) | Constant speed rotation requires speed control (feedback control using speed sensors). Since torque is proportional to current, torque control is easy | |
| How easy it is to obtain | Easy: there are many varieties | Easy:many manufacturers and varieties,many options | Difficulties: mainly special motors for specific applications |
| Price | If the driver circuit is included, the price is expensive. Cheap than brushless motor | Relatively cheap, coreless motor is a little expensive due to its magnet upgrade. | If the driver circuit is included, the price is expensive. |
Performance comparison of micro motors: The radar chart lists the performance comparison of various small motors.
Speed torque characteristics of micro stepping motor:Working range reference (constant current drive)
● Continuous operation (rated): keep about 30% of the torque in the self starting area and out of step area.
● Short time operation (short time rating): keep the torque in the range of about 50%~60% in the self starting area and out of step area.
● Temperature rise: meet the insulation grade requirements of the motor under the above load range and service environment
Summary of key points:
1) When selecting motors such as brush motor, step motor and brushless motor, the characteristics, performance and characteristic comparison results of small motors can be used as a reference for motor selection.
2) When selecting motors such as brush motor, step motor and brushless motor, motors of the same category include multiple specifications, so the comparison results of characteristics, performance and characteristics of small motors are only for reference.
3) When selecting motors such as brush motor, step motor and brushless motor, the detailed information shall be confirmed through the technical specifications of each motor.
Post time: Jan-30-2023