Why do general DC brushless motors have three Halls?
A: In short, in order to be able to rotate, the DC brushless motor must have a certain angle between the magnetic field of the stator coil and the magnetic field of the permanent magnet of the rotor. The process of rotor rotation is also the process of changing the direction of the rotor magnetic field. In order to make the magnetic field of the two have an angle, the magnetic field direction of the stator coil must be changed to a certain extent. So how do you know the direction of the stator magnetic field? Then rely on the three Halls. It can be thought that the three Halls shoulder the task of telling the controller when to change the direction of the current.
★ What is the approximate range of power consumption of the brushless motor Hall?
A: The power consumption of the brushless motor Hall is roughly in the range of 6mA-20mA.
★ How high can the normal motor work at a high temperature? How high can the motor withstand?
Answer: If the temperature of the motor cover exceeds the ambient temperature by more than 25 degrees, it indicates that the temperature rise of the motor has exceeded the normal range. Generally, the temperature rise of the motor should be below 20 degrees. Generally, the motor coil is wound by an enameled wire, and when the temperature of the enameled wire is higher than 150 degrees, the paint film may fall off due to excessive temperature, causing the coil to be short-circuited. When the coil temperature is above 150 degrees, the temperature of the motor casing is about 100 degrees, so the maximum temperature that the motor can withstand is 100 degrees based on the temperature of the casing.
★The temperature of the motor should be below 20 degrees Celsius, that is, the temperature of the motor cover should exceed 20 degrees Celsius, but what is the reason why the motor heats more than 20 degrees Celsius?
Answer: The direct cause of motor heating is caused by large current. Generally, it may be caused by short circuit or open circuit of coil, demagnetization of magnetic steel or low efficiency of motor. Normally, the motor runs for a long time and high current.
★ What causes the motor to heat up? What is the process?
Answer: When the motor load is running, there is power loss in the motor, which will eventually become heat energy, which will increase the temperature of the motor and exceed the ambient temperature. The value at which the motor temperature is higher than the ambient temperature is called temperature rise. Once there is temperature rise, the motor will dissipate heat to the surroundings; the higher the temperature, the faster the heat dissipation. When the heat emitted by the motor per unit time is equal to the amount of heat dissipated, the temperature of the motor no longer increases, but maintains a constant temperature, that is, a state in which heat and heat are balanced.
★What is the temperature rise for general clicks? Which part of the motor is most affected by the temperature rise of the motor? How is it defined?
Answer: When the motor load is running, the load is the greater the output power (if mechanical strength is not considered). However, the greater the output power, the higher the power loss and the higher the temperature. We know that the weakest temperature resistance in a motor is an insulating material, such as an enameled wire. There is a limit to the temperature resistance of insulating materials. Within this limit, the physical, chemical, mechanical, electrical and other aspects of insulating materials are stable, and their working life is generally about 20 years. Beyond this limit, the life of the insulating material is drastically shortened and even burned. This temperature limit is called the allowable temperature of the insulating material. The allowable temperature of the insulating material is the allowable temperature of the motor; the life of the insulating material is generally the life of the motor.
The ambient temperature varies with time and location. When designing the motor, it is required to take 40 degrees Celsius as the standard ambient temperature in China. Therefore, the allowable temperature of the insulating material or the motor minus 40 degrees Celsius is the allowable temperature rise. The allowable temperatures of different insulating materials are different. According to the allowable temperature, the commonly used insulating materials for the motor are A, E, B, F, H. Five kinds.
