Characteristics and Speed Control Methods of DC Motor for Electric Curtains.
The opening and closing of intelligent electric curtains rely on the rotation of micro motors. Some electric curtain motors use AC motors, but with the development of technology, micro DC motors have been widely used in various types of electric curtain products. So what are the advantages of DC motors for electric curtains? What are the common speed control methods?
Electric curtains adopt a micro DC motor and gear reducer structure, which has the advantages of high torque and low speed. Different types of curtains can be driven according to different reduction ratios. Micro DC motors for electric curtains commonly include carbon brush motors and brushless motors. The main advantages of carbon brush DC motors are high starting torque, smooth operation, low cost, and convenient speed regulation. Brushless DC motors have the advantages of long life and low noise, but the cost is too high and the control is complex. Therefore, there are many electric curtains on the market that use carbon brushes.
Electric curtain micro DC motor with various speed control methods
One; When the armature voltage of the DC motor for electric curtains decreases due to speed regulation, the armature circuit needs to have an adjustable DC power supply, and the resistance between the armature circuit and the excitation circuit should be minimized. When the voltage decreases, the speed of the DC motor for electric curtains will also decrease.
Two; DC motor armature circuit series resistance control speed regulation. The larger the series resistance, the weaker the mechanical characteristics and the more unstable the speed. At low speeds, the series resistance is large, resulting in more energy loss and lower power. The speed range is affected by the load, with high load and low load resulting in light load.
Three; Weak magnetic speed regulation, in order to prevent the magnetic circuit of the electric curtain DC motor from being too saturated, the speed regulation can only be weak magnetic and not strong magnetic. The armature voltage of the DC motor is kept at the rated value, and the series resistance of the armature circuit is reduced to the minimum. 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 its mechanical characteristics. When the speed increases, if the load torque is still rated, the motor power will exceed the rated power, and the motor will operate under overload, which is not allowed. Therefore, when the weak magnetic speed is adjusted, the load torque will decrease correspondingly with the increase of motor speed, which is a constant power speed regulation. To prevent the motor rotor winding from being removed and damaged due to excessive centrifugal force, when using weak magnetic field speed regulation, attention should be paid to ensuring that the DC motor speed does not exceed the allowable limit.
Four; In the speed control system of electric curtain DC motor, the simplest method is to change the resistance in the armature circuit to achieve speed control. This method is the simplest and low-cost speed control method, which is very practical for speed control of electric curtains.
The above are the characteristics and speed control methods of the DC motor for electric curtains.
