The protection grade and cooling method are important components of the performance of motor products. The protection grade is the specific requirements for the protection of the motor based on different protection requirements through the design of the components themselves and their coordination. It mainly manifests in key parts such as the motor frame, end cover, bearing system and wiring system. For example, IP23, IP44 and IP54 are common protection grades in small and medium-sized motors. “IP” is the internationally recognized code for protection grades, and the two digits following “IP” respectively represent the degree of protection against dust and liquids.
During the operation of the motor, a certain amount of heat is always generated. To ensure the normal operation of the motor, appropriate cooling measures should be taken to dissipate the heat generated by the motor and ensure that the motor windings and related components operate under safe environmental conditions. The cooling method is represented by the code “IC”, and the numbers following “IC” respectively represent the cooling medium, the cooling medium circuit, the primary cooling medium driving method and the secondary cooling medium driving method. IC01, IC06, IC411, IC416, IC611 and IC616 are common cooling methods for motor products. The cooling method should be matched or correspond to the protection grade of the motor, and be carried out in accordance with the principle of meeting the requirements.
IC01 – The motor uses air as the cooling medium for free circulation cooling. This means that the cooling medium freely enters from the surrounding environment and then directly returns to the surrounding environment, representing an open circuit state where there is only entry and no exit. The movement of the cooling medium is related to the motor’s rotational speed, or it can be due to the action of the rotor itself, or it can be caused by the movement of an overall fan or pump driven by the rotor, which in turn promotes the movement of the medium. Most IP23 motors adopt this cooling method, while there are also cases where the IC06 cooling method is used.
IC06 – It operates with an externally-mounted independent component as the driving medium. The difference from IC01 lies in that an independent component installed on the motor drives the medium to operate, and it is independent of the motor’s speed, such as axial flow fans and centrifugal fans used in variable frequency motors.
IC411 – Air-based enclosure general cooling, that is, the primary cooling medium circulates in the inner circuit of the motor, and the heat is dissipated through the enclosure. The heat dissipation ribs added on the motor base and end cover achieve this effect. The primary and secondary cooling driving modes of this cooling method are both self-circulation modes, that is, related to the motor speed, or due to the action of the rotor itself, or by the action of the overall fan or pump driven by the rotor, to promote the movement of the medium. Most of the closed small and medium-sized industrial frequency motors with IP44, IP54, IP56, etc. adopt this cooling method.
IC611 – Uses air as the medium and has an external cooler. The primary medium circulates in a closed loop and the heat is removed through the cooler; the driving methods of the primary and secondary cooling media are the same as those of IC411. IC616 – Different from IC611, this cooler operates in an independent mode and is not related to the rotational speed of the motor body; it is of forced ventilation structure.
From the above content, we can conclude that most variable-frequency motors adopt forced ventilation structures, while most industrial-frequency motors adopt self-circulation ventilation structures. IC611 and IC616 are the commonly used cooling methods for high-voltage motors and low-voltage power box-type enclosed motors.
Post time: Nov-04-2025