Wind turbines have a problem: Depending on the wind's force, the rotational speed of the turbine and thus of the generator changes. However, alternating current must be fed into the grid with precisely 50 (or 60) hertz. Typically ...
Energy & Green Tech
Feb 23, 2011
7
1
While those wonderful light sabers in the Star Wars films remain the figment of George Lucas' fertile imagination, light mills - rotary motors driven by light - that can power objects thousands of times greater in size are ...
General Physics
Jul 5, 2010
8
2
