Brushed motor is also known as DC motor or carbon brush motor. DC motor is often referred to as brushed DC motor. It adopts mechanical commutation, the external magnetic pole does not move and the internal coil (armature) moves, and the commutator and rotor coil rotate together. , the brushes and the magnets do not move, so the commutator and the brushes are rubbed and rubbed to complete the switching of the current direction.

Disadvantages of brushed motors:

1. The sparks generated by the mechanical commutation cause friction between the commutator and the brush, electromagnetic interference, high noise and short life.

2. Poor reliability and many failures, requiring frequent maintenance.

3. Due to the existence of the commutator, the inertia of the rotor is limited, the maximum speed is limited, and the dynamic performance is affected.

Since it has so many shortcomings, why is it still widely used, because it has high torque, simple structure, easy maintenance (ie, carbon brush replacement), and cheap.

Brushless motor is also called DC variable frequency motor (BLDC) in some fields. It adopts electronic commutation (Hall sensor), and the coil (armature) does not move the magnetic pole. At this time, the permanent magnet can be outside the coil or inside the coil. , so there is a distinction between an outer rotor brushless motor and an inner rotor brushless motor.

The brushless motor construction is the same as the permanent magnet synchronous motor.

However, a single brushless motor is not a complete power system, and the brushless basically must be controlled by a brushless controller, that is, an ESC to achieve continuous operation.

What really determines its performance is the brushless electronic governor (that is, the ESC).

It has the advantages of high efficiency, low energy consumption, low noise, long life, high reliability, servo control, stepless frequency conversion speed regulation (up to high speed), etc. It is much smaller than the brushed DC motor. The control is simpler than the asynchronous AC motor, and the starting torque is large and the overload capacity is strong.

The DC (brush) motor can adjust the speed by adjusting the voltage, connecting the resistance in series, and changing the excitation, but it is actually the most convenient and most commonly used to adjust the voltage. At present, the main use of PWM speed regulation, PWM is actually through high-speed switching to achieve DC Voltage regulation, in one cycle, the longer the ON time is, the higher the average voltage is, and the longer the OFF time is, the lower the average voltage is. It is very convenient to adjust. As long as the switching speed is fast enough, the harmonics of the power grid will be less, and the current will be more continuous. .

Stepper Motor – Open Loop Stepper Motor

(Open-loop) Stepper motors are open-loop control motors that convert electrical pulse signals into angular displacements, and are widely used.

In the case of non-overload, the speed and stop position of the motor only depend on the frequency and number of pulses of the pulse signal, and are not affected by the load change. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate. A fixed angle, called “step angle”, the rotation of which runs step by step at a fixed angle.

The angular displacement can be controlled by controlling the number of pulses, so as to achieve the purpose of accurate positioning; at the same time, the speed and acceleration of the motor rotation can be controlled by controlling the pulse frequency, so as to achieve the purpose of speed regulation.