Dc motor is motor that can transform DC electric energy into mechanical energy, and it can be divided into brush motor and brushless motor.
A brush motor consists of a stator(the static part),rotor(the rotating part) and brush. There is magnetic poles on the stator and wingding on rotor. After electrifying, a magnetic pole is formed on the rotor, and there is a included angle between magnetic pole of rotor and stator. Under the mutual attractions of stator and magnetic pole of rotor, the motor rotates.
From the picture above, we can know that the coil portion of brush motor rotates. The brush is used to make contact with the commutator (copper head) in the winding for the coil to contact electricity and change the direction. The brush can be worn in the rotation, therefore the brush of brush motor need to be replaced after it run out.
Because the commutator can be worn during use, the copper head needs polishing to keep smooth,and the contact area of brush and copper head need to be expanded to improve efficiency. In a word, maintaining brush motor is quite troublesome.
The brush motor is rarely used in multi-axis aircraft,while coreless brush motor is used in some light four-axis device sometimes. Traditional motor rotor is formed by winding coils in a iron core, and rotor of coreless motor consists of a cage woven of coils without iron core, which has characteristics of light weight(no iron core),quick response due to large rotating inertia and energy conversion.
The shortages of brush DC motor:
A.The friction between brush and commutator causes low efficiency, loud noise, easy to heat up and short service life that is several times shorter than that of brushless gear motor.
B.The brush need to be changed regularly
C.Low efficiency and output power for high resistance
D.High interference since the friction between brush and commutator can cause sparks
The characteristics of brush motor:
A.Great performance and high torque
B.The prices is lower than brushless motor
C.Due to the lack of electronic parts, no influence of sensor interference, electronic parts
The brushless gear motor means that the coil part of brushless motor is static,and the rotating part is rotor that contain magnet.
In this situation, three groups of coil plus brushless electric modulation is required to generate changing magnetic fields by continuously changing the current direction of coils, and drive the magnet rotor to rotate constantly. Brushless motor needs brushless electric modulation to work, while brush motor can rotate by connecting the wire to the positive or negative of the power supply.
The shortages of brushless motor
A.brushless electric modulation is required to work together, so the price is higher than brush motor
B.the reliability is influenced by electronic parts, or the motor will fail when the sensor is disturbed.
The characteristics of brushless motor:
A.no friction between brush and commutator, low noise, small vibration, less heat generating ,
long service life
B.no need to change brush, easy to maintain
C.no sparks causing by brush, less interference.
D.excellent torque characteristics, great performance of torque in medium and low speed, large
starting torque and the starting current is small.
ZHAOWEI manufactures gear for brush motor and brushless motor to reduce speed and increase torque，what’s more ,we can provides custom service according requirements of customers