Читать книгу Analysis and Control of Electric Drives - Ned Mohan - Страница 53

In many systems, a linear motion is achieved by using a rotating‐type motor, as shown in Fig. 2-14.

Fig. 2-14 Combination of rotary and linear motion.

In such a system, the angular and the linear speeds are related by the radius r of the drum:

(2-35)

To accelerate the mass M in Fig. 2-14, in the presence of an opposing force f_L, the force f applied to the mass, from Eq. (2-1), must be

(2-36)

This force is delivered by the motor in the form of a torque T, which is related to f, using Eq. (2-35), as

(2-37)

Therefore, the electromagnetic torque required from the motor is

(2-38)