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2023

Brushless stepper small motor difference

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The following table summarizes the characteristics of stepper motors, brushed motors and brushless motors.

	Stepper motor	Brushed motor	brushless motor
Rotation method	Through the drive circuit in order to determine the armature winding phase (two-phase, three-phase, five-phase) excitation.	The armature current is switched by a sliding contact rectifying mechanism of the brush and the commutator.	Brushless is achieved by replacing the functions of a brush and a commutator with a magnetic pole position sensor and a semiconductor switch.
drive circuit	Need	No need	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 at medium to high speed is relatively large)
Rotation speed	proportional to the input pulse frequency. There is out-of-step zone in the low speed range	proportional to the armature applied voltage. The speed decreases as the load torque increases
high speed rotation	Difficult to spin at high speed (need to slow down)	Due to the limitation of brush and commutator rectifier mechanism, up to several thousand rpm	Up to thousands ~ tens of thousands of rpm
rotational life	Determined by the bearing life. tens of thousands of hours	Limited by brush and commutator wear. Hundreds to thousands of hours	Determined by the bearing life. tens of thousands to hundreds of thousands of hours
forward and reverse methods	Need to change the order of the excitation phase of the drive circuit	Reverse the polarity of the pin voltage	Need to change the order of the excitation phase of the drive circuit
Control	Open-loop control where the rotational speed and position (amount of rotation) are determined by the command pulse is possible (but there is a step-out problem)	Constant speed rotation requires speed control (feedback control using a speed sensor). Since the torque is proportional to the current, the torque control is easy
How easy it is to get	Easy: more varieties	Easy: many manufacturers and varieties, many options	Difficulties: mainly dedicated motors for specific applications
Price	If the drive circuit is included, the price is expensive. Cheaper than brushless motors	Relatively cheap, coreless motors are a bit expensive due to their magnet upgrades.	If the drive circuit is included, the price is expensive.

Performance comparison of small motors

The performance comparison of various small motors is listed in the radar chart.

Speed-torque characteristics of small motors

The rotational speed-torque characteristics of each small motor are summarized below. It can be considered that the brushless motor and the brushed motor are basically the same.

Summary of key points：

1) When selecting motors such as brushed motors, stepping motors and brushless motors, 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 motors, stepper motors and brushless motors, the same category of motors includes a variety of specifications, so the characteristics, performance and characteristics of small motors are only used for reference.

3) When selecting motors such as brushed motors, stepping motors and brushless motors, it is finally necessary to confirm the detailed information through the technical specifications of each motor.