(2) High efficiency and light weight make the hollow cup motor have a high power density. Light weight: Power density is the ratio of output power to weight or volume. From the point of view of the internal structure, the hollow cup motor eliminates the iron core, making its own weight and volume smaller, compared with the general core motor of the same power, the weight of the hollow cup motor is reduced by 1/3-1/2, and the volume is reduced by 1/3-1/2. High energy conversion efficiency: Compared to conventional induction coils, copper coils are lighter in weight. Because neither winding nor adding slotted silicon steel sheet is required when winding the coil, the hollow cup motor does not produce eddy current loss and hysteresis loss in this aspect during operation. Although the copper coil will also bring a certain eddy current, but this loss is small and easy to control, ensuring a high output power and output torque. In general, the output power and output torque of the hollow cup motor are higher than that of the ordinary motor of the same specification, and the weight or volume is small, so the power density is high, generally up to 30mW/cm3.

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(3) The smaller rotor inertia makes the hollow cup motor have a faster response speed. Mechanical time constant: refers to the time required when the motor is no-load plus step rated voltage, when the speed reaches 63.2% of the no-load speed, which is one of the main technical indicators to reflect its dynamic performance. Compared with the ordinary brush DC motor of the same size, the rotor inertia of the hollow cup motor is smaller, so it has a higher response speed, and its mechanical time constant is usually within 28ms, and the mechanical time constant of some products is even less than 10ms, and the mechanical time constant of the iron core motor is generally more than 100ms.

(4) No slot effect makes the hollow cup motor run more smoothly. Alveolar effect: The slot effect is due to the uneven distribution of the electromagnetic field, resulting in changes in the density of the magnetic field line at different positions, when the magnetic field line density changes, it will produce a short period of current pulse, although it will not reduce or increase the average torque of the motor, but will cause noise, motor vibration, speed fluctuations, etc. The servo performance and accuracy of motor positioning are greatly affected, especially at low speed. The hollow cup motor removes the iron core and adopts a toothless groove structure, which reduces the magnetic resistance moment of the motor during operation, thus reducing the output torque fluctuation and making the motor run more smoothly.