induction generators used in wind machines only generate after the rated RPM is reached and exceeded.
My question has to do with the SLIP zone of maybe 15-20 rpm after that. The generator can maintain 60 hz
even if the rpm varies in this zone. What I am trying to understand is the limits on this when forces like the wind push against this. How much is too much for slip to maintain a control on the hz..?? 15-20 rpm
seems like an awfully small window to try to control in huge machines like wind turbines and unpredictable
push sources like the wind..???

Hello ip9999

Welcome to the forum.

If you overspeed an induction motor, it becomes an induction generator and generates power back into the supply.
As you increase the torque driving the motor, the slip increases such that the motor is spinning faster than synchronous speed.

The motor exhibits the same slip torque curve while gnerating as it does while "motoring".

As the torque is increased, the slip increases until the maximum torque is driven into the motor. If the torque is increased further, the motor will break away and accelerate well beyond synchronous speed.
The maximum torque will typically be in the order of 250% rated torque. This will occur at the same slip as the maximum motor torque but will be an overspeed condition.

Best regards,
Mark.

so your saying in that 250 % of wind force ,the blades will hold back the extra force and slip will continue to
keep 60 cycle..in otherwords slip makes adjustments to make that happen until the force is too much
and the generator overspeeds and probably triggers a brake..??

Yes that is correct.

Best regards,
Mark.