Let say the rotor frequency is 60Hz and the stator frequency suddenly become 2 Hz or 0 Hz(DC) in 1-2 sec the motor will generate a lot current?
Lets say your AC motor accelerate from stand still and your voltage and frequency is controlled properly, but suddenly the frequency (an error occur) is not proper compared to the voltage (V/f ratio). The stator frequency are still in front compared to rotor frequency. Do the AC motor draw a big current?
Condition of rotor is not important in this case. When the frequency of power supply drops close to zero without any voltage reduction, this case is same that you connect an ac motor to the dc power supply. Generally reduction of motor internal inductance due to frequency drop (Xl=2*pi*f) can be caused a big current.