speed change control of frequency

• 变频调速

speed change control of frequency的用法和样例：

例句

1. The paper introduces the method and effect of boiler fa.
   文章介绍了锅炉引风机采用变频调速实现炉膛负压自动调节的方法以及在工业运行中的效果。
2. This product conforms to the requirements of GMP completely.
   静音设计，变频调速，数显控制介面。