speed-variable pump造句

It is indicated that , when a two - speed motor is used for driving oil transfer pump , the motor with the characteristic of torque reduction on square rotary speed should be chosen ; the working economy of the variable speed pump is restricted by the characteristic curves of pipeline resistance , and its speed control range is restricted by the pipeline resistance characteristic curve , the pressure head needed by the system and the working characteristic of the pump ; when several pumps work in parallel , the pump with better performance should be changed into speed - variable pump
指出双速电动机用于输油泵的调速时，应选用转矩按转速平方降低特性的电动机；调速泵的运行经济性受到管路阻力特性曲线的限制，其调速范围受到管路阻力特性曲线、系统所需扬程和泵运行特性的限制；在母管制系统中把部分定速泵改为调速泵时，应将性能较高的定速泵改为调速泵。
It's difficult to find speed-variable pump in a sentence. 用speed-variable pump造句挺难的