In terms of output characteristics, motor speed regulation can be divided into two categories: stepless speed regulation and step speed regulation. Speaking of specific speed regulation methods, there are many kinds. Here are some common, representative speed regulating motors.
Electromagnetic speed regulating motor: It is composed of single-speed or multi-speed squirrel cage asynchronous motor and electromagnetic slip clutch, which is also called slip motor. It is a constant torque AC stepless variable speed motor. Electromagnetic speed regulation or slip motor has the advantages of wide speed range, smooth speed regulation, large starting torque and low control power. The automatic control system is composed of controller and speed control, high hardness of machanical characteristics, etc. The core of electronmagnetic speed regulation is electromagnetic slip clutch with relative fixed polarity. The claw pole, which distributes alternately between N pole and S pole, rotates under the drive of asynchronous motor, and the solid armature cuts the magnetic force line induces the eddy current, rotates under the action of the claw pole magnetic field, drives the output shaft to output the mechanical power. By adjusting the excitation current of the claw pole, the coupling degree of eddy current field and the magnetic field of the claw pole can be adjusted, or the velocity difference can be saide, so as to realize the speed regulation.
Advantages: Simple structure, small control device capacity, low value. Reliable operation and easy maintenance.
Disadvantages: Speed loss.
Vaeiable-frequency speed regulating motor: The frequency conversion speed regulating motor is the general name of the motor driven by the frequency converter. In fact, the motor designed for the frequency converter is a special frequency conversion motor, the motor can realize different speed and torque under the drive of the frequency converter, in order to adapt to the change of load demand. The frequency conversion motor is developed from the traditional squirrel-cage motor. The traditional motor fan is replaced by the independent fan, and the insulation performance of the motor winding is improved. In the case of low requirement such as low power and frequency working at rated frequency, it can be replaced by ordinary squirrel cage motor. Frequency conversion is to change the synchronous speed of an asynchronous motor by changing the frequency of its stator end power supply and making it continuously adjustable.
Adavantages: No additional slip loss, high efficiency, wide speed range; for low load running time, or running frequently, can achieve the purpose of saving electricity and protecting the motor.
Disadvantages: The technology is more complex and the price is higher.