IEC uses a letter-and-number code to designate how a motor is cooled. The code covers nearly every known cooling method, including those for very large liquid-cooled motors.
IC 01, The first digit means there is free exchange of coolant into and out of the motor. The second digit means the exchange takes place because of “self circulation,” or a fan mounted on the motor shaft.
IC 410, The first digit means the frame surface is cooled; the second digit means that cooling is by convection only with no fanning action. The motor is totally enclosed, non-ventilated (TENV).
IC 411, The first digit again indicates frame-surface cooling, but the second digit shows fanning. This is a fan-cooled motor (TEFC).
IC 416, This motor features an external blower motor on back and therefore is it is totally enclosed blower cooled motor (TEBC).
IC 418, The first digit again indicates frame-surface cooling. The second digit says the coolant and motor move relative to each other.