Advantages and Disadvantages of DC Brushed Motors

The DC brush motor has fast response, large starting torque, and the physical picture of the motor can provide rated torque from zero speed to rated speed. However, its advantages are also its shortcomings, because the DC brush motor requires To produce constant torque performance under rated load, the armature magnetic field and the rotor magnetic field must be constantly maintained at 90°, which requires carbon brushes and commutators. The carbon brushes and commutator will produce sparks and carbon powder when the motor rotates. In addition to causing damage to the components, the use occasions are also limited. AC motors have no carbon brushes and commutators and are maintenance-free, sturdy, and widely used. However, in terms of characteristics, complex control technology is required to achieve performance equivalent to that of DC brushed motors.

Today, the rapid development of semiconductors has accelerated the switching frequency of power components, improving the performance of drive motors. The speed of microprocessors is getting faster and faster, and it is possible to control the AC motor in a rotating two-axis rectangular coordinate system, appropriately control the current components of the AC motor in the two axes, and achieve similar DC motor control and performance comparable to that of a DC motor. performance.

Advantages of brushed DC motors:

1. High energy efficiency, which can reach 80-90%.

2. Good controllability and good linearity of the characteristic curve.

3. The technology is mature and widely used.

Disadvantages of brushed DC motors:

1. The service life is short. The brush is a wearable product and needs to be replaced after several thousand hours.

2. There is noise caused by carbon brush friction.

3. There are electric sparks, which are generated when the carbon brushes are reversed. In serious cases, they will interfere with the normal use of other electrical appliances.

4. Many occasions where it is used are affected by brushless DC motors.

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