Читать книгу Analysis and Control of Electric Drives - Ned Mohan - Страница 57
Optimum Gear Ratio
ОглавлениеEquation (2-43) shows that the electromagnetic torque required from the motor to accelerate a motor‐load combination depends on the gear ratio. In a basically inertial load where TL can be assumed to be negligible, Tem can be minimized, for a given load‐acceleration , by selecting an optimum gear ratio (r1/r2)opt.. The derivation of the optimum gear ratio shows that the load inertia “seen” by the motor should equal the motor inertia, that is, in Eq. (2-44),
(2-45a)
and, consequently,
(2-45b)
With the optimum gear ratio, in Eq. (2-43), using TL = 0, and using Eq. (2-41),
(2-46)
Similar calculations can be made for other types of coupling mechanisms (see homework problems).