主元件 meaning in English

main unit
master element
primary element

Introductory element - main element - complementary element
引导元件.主元件.辅助元件
It is necessary to study the mechanism of harmonics generation , make sure the content and distribute of harmonics current in order to alleviate their harm to traction power system ' s component , equipments of protect and measure as well as other customer ' s electronics equipments
为了从根本上抑制电力牵引负荷谐波带来的影响，削弱谐波对牵引供电系统主元件、保护测控装置和其他用户电子设备的影响，有必要研究电气化铁道牵引谐波产生的机理，确定馈线电流谐波的含量与分布状况。