admin answers:

For the efficiency calculation the formula

Power in wind = (density of air ) x (turbine blade diameter)2 x( velocity of wind)3 x (a constant)

Power in wind = d x D2 x v3 x c

Notice that the power in the wind depends on the density of the air, the diameter of the turbine blades squared (D times D), and the velocity of the wind to the third power (V times V times V). There is also a constant in there which I’ll discuss in the very next paragraph.

What about that constant, C? It’s there because what we are really interested in is the Area swept by the blades of diameter, D. The area is calculated by multiplying the number Pi (approximately 3.14159) times the diameter squared divided by 4. So part of the constant, C, is just the constant number Pi divided by 4 pulled out to show us that the important variable in the area formula is D. The other part of the constant, C, can be whatever unit conversion numbers are needed to make sure the numbers come out right. For now, we won’t go further into that. The point is that the variables that determine the wind power blowing into a wind turbine are air density, blade diameter (resulting in a certain swept area), and wind velocity.

You have probably noted that power (not energy) is dependent on the velocity times itself 3 times (V x V x V). Whoa! In other words, if the wind speed doubles, the power available from the wind increases by a factor of eight. The diameter is significant too. Doubling that increases the power by 4 times. Faster is better, and bigger is better (if you can afford it and can build it strong enough).

Of course, the wind doesn’t blow all the time in most places and when it blows too hard the turbine blades can break or spin so fast they break off (not good when each blade can weigh several tons). In that case, the blades are usually “feathered” to reduce stresses on them and to slow them down. This means we can’t take advantage of really high wind speeds.

Turbine Efficiency

If the turbine could convert all the wind’s power to mechanical power we would say it was 100% efficient. But as you probably know, the real world is never so generous. To even achieve 50% is unlikely, and would be a very efficient machine. A 50% efficient turbine would convert half of the power in the wind to mechanical power.

Hope this will solve your problem

Regards

For other references

Efficiency Varies with Wind Speed
A given wind turbine has a “design point” that generally defines its peak efficiency at the wind speed for which the system is designed. At wind speeds above and below the design speed the efficiency is the same or less – maybe much less. If a turbine’s best efficiency is 40% at a wind velocity of 9 meters per second (about 20 mph), it will be 40% only at that wind speed. At all other wind speeds it will be something worse. That wind turbine will generally operate at lower than its best efficiency, because wind speeds are never constant or average.

The electric power actually produced will be still lower because the generator efficiencies are also less than 100% (generally in the mid- or low-90’s at best), and there are further losses in the conversion electronics and lines. But this is true of all power technologies. When all these losses are figured in, you might, if you are lucky, be getting 35% or so of the wind’s energy actually delivered as useful electrical energy to the end user in the very best conditions. The average might only be in the twenties.

In the formula above, then, we have to add one more number that I don’t show. That number is an efficiency number that would have to supplied by the manufacturer of the wind turbine, or experimentally determined by you if you make it yourself. It will not be one number, but a variable that is a function of wind speed.

admin answers:

It depends. You didn’t say what kind of motor it was. Is it an AC motor? DC?
What configuration is it?

If its armature has a commutator, then it can be configured as a pulsed DC generator and you will need to do the filtering of that waveform. But you may have to make changes depending on the configuration. You need to be more specific. Surely there is model number and manufacturer plate.