The opening and closing of smart electric curtains rely on the rotation of micro motors to achieve. Some electric curtain motors use AC motors, but with the advancement of technology, micro DC motors have been widely applied to various types of electric curtain products. So, what are the advantages of DC motors used in electric curtains? What are the common speed control methods? Electric curtains use micro DC motors with gear reducers, which have the advantages of high torque and low speed, and can drive different types of curtains based on different reduction ratios. Common micro DC motors in electric curtains are brushed motors and brushless motors. The main advantages of brushed DC motors include high starting torque, smooth operation, low cost, and convenient speed control; brushless DC motors have the advantages of long life and low noise, but their cost is higher, and control is more complex. Therefore, there are many electric curtains on the market that use brushed motors.
Different Speed Control Methods for Micro DC Motors in Electric Curtains
1. When the speed of the electric curtain DC motor is adjusted by reducing the armature voltage, the armature circuit requires a regulatable DC power supply, and the resistance of the armature circuit and the excitation circuit should be as small as possible. When the voltage is reduced, the speed of the electric curtain DC motor will also decrease correspondingly.
2. Speed control by 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 large series resistance, more energy is lost, and the power is lower. The speed control range is affected by the load, that is, different loads result in different speed control effects.
3. Weak magnetic speed control, to prevent the magnetic circuit of the electric curtain DC motor from being overly saturated, the speed control should use weak magnetism instead of strong magnetism. The armature voltage of the DC motor is kept at the rated value, and the series resistance in the armature circuit is minimized. The excitation current and magnetic flux are reduced by increasing the excitation circuit resistance Rf, thereby increasing the speed of the electric curtain DC motor and softening the mechanical characteristics. When the speed rises, if the load torque remains at the rated value, the motor power will exceed the rated power, causing the motor to operate overloaded, which is not allowed. Therefore, when weak magnetic speed is adjusted, the load torque will decrease correspondingly with the increase of the motor speed. This is a constant power speed control. To prevent the motor rotor winding from being dismantled and damaged due to excessive centrifugal force, attention should be paid not to exceed the allowed limit of the DC motor speed when using weak magnetic field speed control.
4. In the speed control system of the electric curtain DC motor, the simplest way to complete the speed control is by changing the resistance in the armature circuit. This method is the simplest and has the lowest cost, and it is very practical for the speed control of electric curtains.
These are the characteristics and speed control methods of DC motors used in electric curtains.
Post time: Dec-19-2024