Error is Inf or NaN with wind turbine

I simulate generator with wind turbine and have a problem that this error is show: "Derivative input 1 of 'Model07/Generator/Integraor2' at time 6.3840226536120968 is Inf or NaN. Stopping simulation. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)"

while if constant or step replace with turbine this error not shown. Please help me?