The opening and closing of smart electric curtains are driven by the rotation of micro motors. Initially, AC motors were commonly used, but with technological advancements, DC motors have gained widespread application due to their advantages. So, what are the advantages of DC motors used in electric curtains? What are the common speed control methods?
Electric curtains utilize micro DC motors equipped with gear reducers, which offer high torque and low speed. These motors can drive various types of curtains based on different reduction ratios. The common micro DC motors in electric curtains are brushed motors and brushless motors. Brushed DC motors have advantages such as high starting torque, smooth operation, low cost, and convenient speed control. Brushless DC motors, on the other hand, boast a long lifespan and low noise levels, but they come with higher costs and more complex control mechanisms. Consequently, many electric curtains on the market employ brushed motors.
Different Speed Control Methods for Micro DC Motors in Electric Curtains:
1. When adjusting the speed of the electric curtain DC motor by reducing the armature voltage, a regulatable DC power supply is required for the armature circuit. The resistance of the armature circuit and the excitation circuit should be minimized. As the voltage decreases, the speed of the electric curtain DC motor will correspondingly reduce.
2. Speed control by introducing series resistance in the armature circuit of the DC motor. The larger the series resistance, the weaker the mechanical characteristics, and the more unstable the speed. At low speeds, due to the significant series resistance, more energy is lost, and the power output is lower. The speed control range is influenced by the load, meaning different loads result in varying speed control effects.
3. Weak magnetic speed control. To prevent excessive saturation of the magnetic circuit in the electric curtain DC motor, speed control should utilize weak magnetism instead of strong magnetism. The armature voltage of the DC motor is maintained at its rated value, and the series resistance in the armature circuit is minimized. By increasing the excitation circuit resistance Rf, the excitation current and magnetic flux are reduced, thereby increasing the speed of the electric curtain DC motor and softening the mechanical characteristics. However, when the speed increases, if the load torque remains at the rated value, the motor power may exceed the rated power, causing the motor to operate overloaded, which is not permissible. Therefore, when adjusting the speed with weak magnetism, the load torque will correspondingly decrease as the motor speed increases. This is a constant power speed control method. To prevent the motor rotor winding from being dismantled and damaged due to excessive centrifugal force, it is important not to exceed the allowed speed limit of the DC motor when using weak magnetic field speed control.
4. In the speed control system of the electric curtain DC motor, the simplest way to achieve speed control is by altering the resistance in the armature circuit. This method is the most straightforward, cost-effective, and practical for the speed control of electric curtains.
These are the characteristics and speed control methods of DC motors utilized in electric curtains.
Post time: Aug-22-2025