What is a differential motor?

Some introductions: For details, please refer to the Tianjin Micro Motor website at http://www.cz21315.cn/index.htm. These refer to motors with small size and capacity, whose output power is generally below a few hundred watts, as well as motors that have special requirements in terms of application, performance, and operating conditions. The full name is micro special motor, abbreviated as micromotor. It is commonly used in control systems to perform functions such as the detection, processing, amplification, actuation, or conversion of electromechanical signals or energy. It can also be used to drive mechanical loads, as well as serving as an AC or DC power source for equipment. There are a wide variety of micro and special motors, which can be broadly classified into 13 categories: DC motors, AC motors, permanent magnet motors, stepper motors, rotators, shaft angle encoders, AC/DC dual-use motors, tachogenerators, synchroscopes, linear motors, piezoelectric motors, motor assemblies, and other special motors. Micro and special motors can be broadly classified into 3 types in terms of structure: ① Electromagnetic type. Its basic structure is similar to that of a regular motor, including components such as the stator, rotor, armature windings, and brushes, but it has an exceptionally compact design. ②Modular. There are two common types: combinations of the various micro-motors mentioned above ； A combination of micro-motors and electronic circuits. For example, combinations of DC motors and sensors, combinations of linear motors in the X direction and Y direction, etc. ③Non-electromagnetic. The external structure is the same as that of electromagnetic types; for example, rotary products are designed in a cylindrical shape while linear products are designed in a square shape. However, the internal structure varies greatly due to differences in their working principles. The performance of various micro and special motors varies greatly, and it is difficult to uniformly define their performance parameters. Generally speaking, those used to drive machinery focus on the power parameters during operation and starting ； For use as a power source, factors such as output power, waveform, and stability need to be considered ； Control micromotors focus on static and dynamic characteristic parameters. The characteristic parameters of the first two types of motors are similar to those of ordinary motors. Only the micro motors used for control have their unique characteristic parameters. ①Job characteristics. It is commonly expressed in terms of the relationship between input and output values, or between one output value and another. In terms of control requirements, the static characteristic curve should be continuous and smooth, without any abrupt changes ； Dynamic characteristics are commonly represented by frequency curves or response curves. The frequency curve should be smooth, without any sudden jumps or oscillations ； The response curve should converge rapidly. ②Sensitivity. The magnitude of the output corresponding to a unit input signal. It is generally expressed using terms such as specific torque, specific electromotive force, and amplification factor. ③Accuracy. Under certain input conditions, the difference between the actual value of the output signal and its theoretical value represents the precision of the micromotor, which is commonly expressed in terms of error magnitude. ④Impedance or resistance. In the system, the input and output impedances of the micromotor should match those of the corresponding circuits, in order to ensure the system’s operational performance and accuracy. ⑤Reliability. These requirements apply not only to control micro motors, but also to drive micro motors and power micro motors. Parameters such as useful life, failure rate, reliability, and mean time between failures are commonly used to characterize the operational reliability of micro motors. Micro and special motors are mainly applied in 3 fields: ① as power sources for moving machinery loads in driving applications where no special control requirements exist. ②Audio-visual equipment. For example, in video cassette recorders, the micro motor is not only a key component of the drum assembly but also an essential element for driving the main shaft, enabling the automatic loading and unloading of the tape, as well as controlling the tape tension. ③Office automation equipment, computer peripherals, and industrial automation equipment. Micro and special motors are used in devices such as disk drives, copiers, CNC machines, robots, and so on.