Giridhar,

Difficult to answer your quention in too much detail here. Suffices to say that you need to improve upon (perhaps even redesign) the mechanics at the hub and nacelle.

-Sanjay

What is the rating of your wind generator? it seems it is very less. Apply a load of milli watts and check.

you need to use storage that plays as an energy reserve when the it is under the cut speed

Its 10kw alternator,when i apply a 10w load it took more torque to drive it,but for large load it is operating normally.

i used strong neobdynum magnets in rotor ,the field coils exciting same for small and large load so i think stator attracts rotor some what so ,it taking some more torque than the required.

so tell me how to reduce this problem.

Yes Giridhar, you are right in your judgement.

Now I get your problem (sorry your first message made it look as though the problem is in the turbine side !).

This is a common issue with PM rotors, and is known as detent torque. In fact in small PM stepper motors it is used to an advantage of making servo positions stable.

In this case, I would suggest two options:

-Sanjay 

Thank you,I maintained uniform air gap between stator and rotor ,& i think there is no bad mechanical position of the rotor. can u tell me detent torque cancellation mechanism.

Giridhar,

If what you say about non-saliency and perfectly uniform air gap is really true, frankly speaking there should be no detent torque. So there is some detent effect creeping in, and I would suspect an off-centre rotor (hence a minor non-uniformity of air gap).

The detent torque cancellation will require cancellation current in the windings. For details, check any good book on PM motors.

I would once again check for off-centre rotor thoroughly if I were in your position.

-Sanjay

thanks sanjay,i will check it.