Some people labor under a stubborn misundertanding that these units refer to the flow of compressed volume (as opposed to free air volume), but this is flatly wrong. The confusion arises because the term "cubic foot" sounds like a measure of volume, when in fact this term in this context...
Breakdown torque is the maximum torque a motor develops when operated at its rated voltage and frequency without a sudden drop in RPM. If the load on a motor is increased enough beyond its horsepower rating, the speed of the motor will drop without any warning and the motor may stop turning...
In the case of motors, significant parameters are critical torques, such as starting or locked-rotor, pull-in, and pull-out torques for synchronous motors, and locked-rotor, pull-up or minimum, and breakdown or maximum torques for induction motors. Typical torque–speed and current–speed ...