Variable speed motor applications and principles

Usually, the work part of the motor is rotated. This type of motor is called a rotor motor. It is also called a linear motor. Motors can provide a wide range of power, from milliwatts to 10,000 kW. The use and control of the motor is very convenient. It has the ability of self-starting, accelerating, braking, reversing, slamming, etc. It can meet various operational requirements. The motor has high working efficiency, no smoke, odor, no pollution, no noise. Also small. Because of its series of advantages, it is widely used in industrial and agricultural production, transportation, national defense, commercial and household appliances, medical electrical equipment and other aspects.
The most widely used of various motors is an AC asynchronous motor (also known as an induction motor). It is easy to use, reliable in operation, low in price, and firm in structure, but with low power factor and difficult speed regulation. Synchronous motors are commonly used in high-capacity, low-speed power machines (see Synchronous Motors). The synchronous motor not only has a high power factor, but its speed is independent of the load and is determined only by the grid frequency. The work is more stable. DC motors are often used where wide-range speed regulation is required. However, it has a commutator, which is complicated in structure, expensive, difficult to maintain, and unsuitable for harsh environments. After the 1970s, with the development of power electronics technology, the speed control technology of AC motors has gradually matured, and the price of equipment has been decreasing, and it has begun to be applied. The maximum output mechanical power that the motor can bear under the specified working mode (continuous, short-time operation, intermittent cycle operation) and not cause the motor to overheat is called its rated power. Pay attention to the requirements on the nameplate when using it. . When the motor is running, care should be taken to match the characteristics of the load with the characteristics of the motor to avoid flying or stopping. There are many speed control methods for electric motors, which can adapt to the requirements of different production machinery speed changes. In general, the output power of the motor will change with the speed when the speed is adjusted. From the perspective of energy consumption, the speed regulation can be roughly divided into two types: 1 keeping the input power constant. By varying the energy consumption of the governor, the output power is adjusted to adjust the speed of the motor. 2 Control the motor input power to adjust the speed of the motor.

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