variable-speed unit

In this article, a compact structure and energy-saving variable frequency close hydraulic power unit is introduced. The control character of this unit using PID has studied. The response characteristic of the system has improved using PID control.

针对一种结构紧凑、节能的变频闭式液压动力单元进行了PID控制特性仿真研究，采用PID控制时能改善系统的的响应特性，使系统速度和压力达到预定的控制效果。

Its fixed cost is $ 3. The variable cost unit is $ 30 and price is $ 5 unit.

固定成本是3美元, 单位变动成本是30美元,单位售价5美元.

Design of Guide Rail for the Variable Magnification Unit and Compensation Unit in Zoom Lens

变焦距镜头变倍组和补偿组移动导轨的设计

After the transformation of the flow path of a certain unit, there exits excessive negative differential expansion under normal operation condition, which seriously impacts the varying duty and the variable parameter characteristics of the unit.

某型号机组经过通流部分改造后存在着正常运行状态下负胀差偏大的问题，严重影响机组的变负荷特性及变工况特性。

Division Y has determined that the fitting would require variable costs of $ 8 per unit.

y部门已计算出每单位配件的变动成本为8美元.