why do wind turbines turn when there is no wind

ВThe short answer is that if they move slowly, they produce less power. But if the wind speed doubles, then a windmill could produce eight times more power under the appropriate conditions. If there is too little wind and the blades are moving too slowly, the wind turbine no longer produces electricity. The turbine starts to create power at what is known as the cut-in speed. Power output continues to grow as the wind speed increases, but at a slower rate than it does right after the cut-in point. The turbine then reaches its maximum rated wind speed, above which the power output holds steady under ideal conditions, generally 22 to 36 miles per hour, depending on the type of windmill. Of course, too much wind could damage the turbine, so windmills have a cut-out speed, too.


After that, a brake stops the windmillвs rotation. Windmills are generally rated to the power they would produce in ideal conditions. That means the rated power can be different from the actual power produced, because wind conditions depend on seasons and time of day. For example, the
в130 turbines slated to be located off Cape Codвis rated to produce up to 468 megawatts of wind power. But the average production will only be 170 megawatts, based on varying conditions such as wind speed and wind regularity. Those estimates are based on measurements of wind made before a site is built, so that a wind farm can be designed to harness the maximum power available. This information is crucial to the efficient utilization of wind power on the existing electric power grid.


The housing behind the blades contains the machinery that actually creates the electricity. A gear system increases the original rotational speed of the blades to the high speed needed to generate electricity, converting the mechanical movement of the blades into power. Occasionally the power available from a wind farm cannot be used, because the consumer demand isnвt there. A great deal of research is currently being done on electricity storage systemsвbatteries are one exampleвso that the power produced by this type of renewable energy can be stored and used when itвs needed. You're question refers to synchronous machines. This is not the easiest concept to explain here and would take some research on your part.


As far as I'm. You re question refers to synchronous machines. This is not the easiest concept to explain here and would take some research on your part. As far as I m aware basically all wind turbines designed to supply electricity to a grid are designed using a synchronous machine generator to convert the rotational energy produced by the wind on the fins into electrical energy. Synchronous generators work by spinning at constant speeds and what happens when there is a lack of wind, the generator will actually TAKE electricity FROM the grid to supply the energy required to keep the wind turbine spinning, rather than letting it stop. This is to do with 3-phase AC electricity and magnetic forces.


The same actually begins to happen if the wind begins to spin the turbine too quickly, power is provided by the grid to slow down the turbine. It may sound daft, but theres a good reason for it (to do with the 60/50Hz frequency that the supply to your home operates at) My best advice would be to google Synchronous Machines and/or find an Power (or Electrical) Engineer who still knows all their stuff from University. The reason why they would keep the turbines spinning without any wind? You may be correct about them seizing up, but I kind of doubt it unless you live in a place with very low temperatures? Sometimes power stations produce too much electricity as well so this would be a good way to dispense of excess electrical production.

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