DC blowers have been around for a long time in our live […]
DC blowers have been around for a long time in our lives. They are used in industries, shopping malls, hospitals and other places. It can be said that if you look carefully, you will surely find it around.
DC motors are often used in DC blowers. The basic DC motor relies on carbon brushes and commutation rings to switch the current direction, thereby switching the polarity of the magnetic field in the rotating armature. The interaction between the inner rotor and the fixed permanent magnet causes it to rotate. In EC motors, mechanical commutation has been superseded by electronic circuitry that provides the right amount of armature current in the right direction at the right time for precise motor control. By using a compact external rotor design and fixed windings to further simplify the problem. Permanent magnets are installed in the rotor near the fan impeller.
Brushless DC motors have existed for many years, but always require a separate DC power supply. In applications that use only AC power, this adds cost and complexity. Then in 2003, ebm-papst brought out an integrated electronic EC fan that could be connected directly to AC power. In addition to performing the commutation, the electronics convert the AC to DC and control the fan speed by adjusting the motor's power.
In short, DC motors are about 30% more efficient than AC motors because the secondary field comes from permanent magnets rather than from copper windings. AC motors consume only extra energy to generate a magnetic field by inducing a current in the rotor. But this is only half the story. The use of modern electronics in motor control opens up many other possibilities that help to reduce electricity consumption
In order to control the motor accurately and effectively, the integrated electronics must continuously monitor the motor speed and adjust the control input. By making the circuit available to external sources, a simple speed control option can be provided. There is no need to worry about the DC power to the sensor, which is provided by another connection on the motor. In fact, just connect a potentiometer, you can stepless speed regulation. No triac, no inverter, no noise!