variable frequence variable speed的用法和樣例：
例句
- The imported frequency control of motor speed adapts to different printing speeds.
進(jìn)口變頻電機調速，適應不同印刷速度。 - The doffer is driven by an inverter and a synchronous toothed belt which permits stepless variations of the speed.
道夫采用變頻電機，同步齒形帶傳動(dòng)，實(shí)現無(wú)級調速。
