The rated speed of 4000RPM is the maximum speed at which the motor still produces its rated torque. At speeds higher than 4000RPM the motor will still run, but at a lower output torque than what is rated.
The rated speed of 4000RPM is the maximum speed at which the motor still produces its rated torque. At speeds higher than 4000RPM the motor will still run, but at a lower output torque than what is rated.