Brushless DC motor uses semiconductor switching devices to achieve electronic commutation, that is, electronic switching devices instead of traditional contact commutator and brush. It has the advantages of high reliability, no commutation spark and low mechanical noise, and is widely used in recording stands, video recorders, electronic instruments and automated office equipment.
Brushless DC motor consists of permanent magnet rotor, multi pole winding stator, position sensor and so on. The position sensor commutates the current of the stator winding according to the change of the rotor position in a certain order (i.e. detects the position of the rotor magnetic pole relative to the stator winding, and generates the position sensing signal at a certain position. After the signal conversion circuit is processed, the power switching circuit is controlled and the winding is carried out according to a certain logical relationship. Current switching. The work of stator windings.
What aspects do we need to start with when we buy brushless DC motor? What problems should we pay attention to? The following Demag motor to give you one or two, in the purchase of brushless DC motor selection time may as well compare to see if it is useful.
1. pay attention to the voltage of Brushless DC motor.
The voltage is supplied by the electronic switch circuit controlled by the position sensor output. Choose DC brushless motor products should first choose the correct voltage, according to customer needs to choose the rated voltage to choose the driver voltage parameters, pay attention to the use of voltage in the no-load and full-load process do not exceed the range set by the driver.
2. pay attention to the current of Brushless DC motor.
We choose the peak current of the driver by selecting the rated input current Ir (A) of the motor, then the peak current Ip (A) = 2xIr. Otherwise, there is no engineering allowance for the output current of the driver during use. If the rated output power (or output power) Pr (W) and the driving voltage Vr (V) of the motor are known, then the peak current will be zero. The value current Ip (A) is greater than 4xPr/Vr..
3. pay attention to the use temperature of Brushless DC motor.
We can also set the motor according to the parameters, but we need to set it according to different motor parameters, of course, we need to take into account the temperature range of use, the wider the temperature, the higher the price.
4. pay attention to the resistance of Brushless DC motor.
According to the requirements of power insulation, in order to ensure the normal operation of the driver, the insulation resistance between the Hall wire and the motor winding wire, the Hall wire winding wire and the casing is greater than 100 MHz 500VDC, and can withstand 600VAC/50Hz/1mA/1 second voltage withstanding without breakdown.
Special attention: DC brushless motor driver brake using motor end short-circuit brake, motor operation there is braking force, not running there is no braking force, the higher the speed of braking force. Because the brake current does not pass the current sensing resistance, the brake current can not be controlled. Therefore, the braking speed should not exceed the safe braking speed, otherwise the power tube may be burned out, this function should be used with caution.