It produces the same torque at any speed below its base speed, which means power below base speed falls off with RPM. Above base speed, power is constant, which means torque falls off as speed increases. So, you'll have full torque at any frequency up to 50Hz, and decreasing torque above that speed. At 100 Hz, torque will be half what it is at 50Hz. If it's a 1HP motor, it will deliver 1 HP at 50Hz and above, but only 1/2 HP at 25Hz.
Regards,
Ray L.