varying frequency speed controner的用法和樣例：
例句
- When the frequency changer has malfunction, power frequency is adopted, and the motor speed is nonadjustable.
萬(wàn)一變頻器出現故障時(shí)，可工頻驅動(dòng)，轉速不可調。 - The paper mainly introduces the technology of adjusting speed of convertor and its superiority.
主要介紹變頻器的調速技術(shù)及使用變頻器的優(yōu)越性。
