Methods for adjusting the speed of series-excited motors Working principle of speed regulation of series-excited motors

Working principle of series motor speed regulation

The principle of series motor speed regulation can be explained in the following steps:

1. Change the excitation current: By changing the current of the series motor excitation winding, the excitation magnetic field strength of the motor can be changed. When the current increases, the excitation magnetic field strength increases, and the motor speed will also increase. Conversely, when the current decreases, the motor speed will also decrease.

2. Change the power supply voltage: By changing the power supply voltage, the motor speed can be changed. When the power supply voltage increases, the motor speed will also increase. Conversely, when the power supply voltage decreases, the motor speed will also decrease.

3. Control the load of the motor: By changing the load of the motor, the speed of the motor can be changed. When the load increases, the speed of the motor will decrease. Conversely, when the load decreases, the speed of the motor will increase.

Through the above steps, the speed regulation of the series-excited motor can be realized. In practical applications, different speed regulation methods and control strategies can be adopted as needed.

Method for adjusting the speed of series motor

There are three factors that affect the speed of a single-phase series-excited motor, namely, power supply voltage, magnetic flux and the number of conductors. That is, the speed of the motor can be changed as long as one or more of these factors change.

The number of conductors is an inherent parameter of the motor and cannot be adjusted in the finished motor. Therefore, in the actual process, the speed is adjusted by the power supply voltage and magnetic flux. The more commonly used speed regulation methods are:

1) A thyristor or reactor is connected in series between the voltage and speed regulating power supply and the internal feed lead of the motor;

2) Magnetic speed regulation changes the magnetic flux size through series-parallel conversion and graded tapping, thereby changing the motor speed;

3) Series resistance speed regulation is essentially still voltage regulation speed regulation, but the series inductor is replaced with a variable resistor, which can smoothly change the terminal voltage of the motor and achieve stepless speed regulation.

Can the series motor reduce the voltage to adjust the speed?

The speed of a series-excited motor can be controlled by reducing the voltage. When the voltage is reduced, the motor speed also decreases. If the load remains unchanged, the motor speed is proportional to the voltage. Generally, the speed can only be reduced. To increase the speed, the voltage must be increased, and the range is very small.

The angle grinder motor can be speed-controlled by a voltage-regulating transformer.

Yes, it is easier to change the speed through stepless voltage regulation of thyristor, such as the speed regulation of electric drill.

Which is better, a series motor or a DC motor?

Series motors and DC motors each have their own advantages and applicable occasions. Series motors have higher speeds and higher torques, can operate at different voltages, and have a wide range of applications. The housing of this type of motor has a high degree of protection to prevent the intrusion of external dust and water, so it is particularly suitable for use in harsh environments. The DC motor has a simple structure and high reliability. It has good regulation performance and high conversion efficiency, and responds quickly to load changes. In specific applications, such as equipment that requires precise speed control, the DC motor is the only choice. In addition, the DC motor can withstand higher loads and has good frequent start/stop performance. In summary, both have their own characteristics, and which motor to choose depends on your specific needs and usage scenarios.