DC Motor Control Circuit Album—1

Note: DC motors are widely used in household appliances, electronic instruments and equipment, electronic toys, video recorders and various automatic controls. However, many readers are not familiar with its use and control, and its technical information is also difficult to find. The collection of DC motor control circuits will make readers "get it all without any effort"! In modern electronic products, automatic control systems, electronic instruments and equipment, household appliances, electronic toys, etc., DC motors have been widely used. The familiar tape recorders, record players, video recorders, electronic computers, etc. cannot lack DC motors. Therefore, the control of DC motors is a very practical technology. This article will introduce the control technology of various DC motors in detail.
A few words from the webmaster: The content of this article is relatively detailed and complete, but unfortunately the printing quality and drawing of the original manuscript are indeed very poor. Although many measures have been taken, some pictures may still not be clear.
DC motors can be roughly divided into four categories:
The first category is stepper motors with several phase windings. These stepper motors, with the addition of appropriate sequence pulses, can make the main shaft rotate a precise angle (usually between 1.8°--7.5°). As long as the appropriate pulse sequence is applied, the motor can rotate continuously at a predetermined speed or direction.
Stepper motors are easily controlled by microprocessors or dedicated stepper motor driver integrated circuits. For example, the commonly used SAAl027 or SAAl024 dedicated stepper motor control circuits.
Stepper motors are widely used in places where accurate measurement of angle rotation is required. For example: the movement of robot arms, character selection of advanced character wheels, head control of computer drives, head control of printers, etc., all require stepper motors.
The second category is permanent magnet inverter DC motors, which are very simple in design but extremely widely used. When the rated DC voltage is applied, the speed is almost the same. This type of motor is used in machines or equipment with fixed speeds, such as recorders, video recorders, record players or laser record players. It is also used in drive devices with a wide speed range, such as small electric drills, model trains, electronic toys, etc. In these applications, it greatly enhances the function of the motor with the help of electronic control circuits.
The third category is the so-called servo motor, which is an actuator in an automatic device. Its biggest feature is controllability. When there is a control signal, the servo motor rotates, and the speed is proportional to the control voltage. When the control signal voltage is removed, the servo motor stops rotating immediately. Servo motors are widely used and are needed in almost all automatic control systems. For example, the speed measuring motor, its output is proportional to the speed of the motor; or the gear box drives the potentiometer mechanism, its output is proportional to the position of the potentiometer. When this type of motor is matched with an appropriate power control feedback loop, its speed can be accurately locked to the frequency of an external oscillator, or locked to an external displacement control knob.
Servo motors are often used in turntables of record players or laser players. Servo motors are also used in antenna rotation systems, remote control model aircraft and ships.
The last category is two-phase low-voltage AC motors. This type of motor is usually a DC power supply to a low-frequency oscillator, and then uses low-frequency and low-voltage AC to drive the motor. This type of motor is occasionally used in turntable drive mechanisms.