What are the basic advantages of coreless motors?

What are the basic advantages of hollow cup motors?

1. High power density: The power density of hollow cup micro motors is the ratio of output power to weight or volume. The coreless rotor is lighter than the ordinary core rotor. The coreless rotor eliminates the eddy current and hysteresis losses generated by the core rotor, improves the efficiency of the micro motor, and ensures higher output torque and output power;

2. High efficiency: The coreless rotor has no eddy current loss and hysteresis loss, and the resistance is very small, which reduces copper loss;

3. No torque lag: The coreless rotor has no hysteresis loss, so the speed and torque fluctuations are reduced;

4. No cogging effect: Ordinary micro motors will produce cogging effect under the interaction between slots and magnets, while hollow cup motors eliminate this effect, so neither cogging effect nor torque lag will exist;

5. Low starting torque: Due to no hysteresis Loss, no cogging effect, so the starting torque is very low, usually the bearing load is the only obstacle;

6. High-speed coil: The inductance value parameter is important when the micromotor is running at high speed. A small inductance value will make the starting voltage low. By increasing the number of poles and reducing the thickness of the casing, the inductance value table helps to reduce the weight of the micromotor while increasing the power density;

7. Fast response: Due to the low inductance value of the micromotor, the current responds quickly to voltage fluctuations, the rotor has a small moment of inertia, and the torque and current response speed are equivalent, so the rotor acceleration is about 2 times that of an ordinary iron core motor;

8. Good heat dissipation: There is air flow on the surface of the hollow cup rotor, which has better heat dissipation performance than the iron core rotor. The enameled wire of the iron core rotor is embedded in the silicon steel sheet slot, and there is less airflow on the coil surface, and the temperature rise is large. Under the same power output conditions, the temperature rise of the hollow cup DC motor is small.

Disadvantages of hollow cup motors: When the coreless hollow cup micromotor is in a stationary state, if one phase of the winding is cut off or the power is cut off and one phase is connected to the power supply, the magnetic field points generated by the winding are equal in magnitude and rotate in opposite directions. The torques generated by them and the rotor are equal in magnitude and opposite in direction, which cancel each other out. The motor cannot start under zero starting torque. This is the disadvantage of the hollow cup motor.