Protection grade is an important performance parameter of motor products, which is directly related to the working conditions of motor products. The content of motor protection grade should be realized by specific parts such as seat, end cover, bearing cover, junction box, shaft surface oil seal and so on. The most commonly used IP23 and IP54 motors are obviously different from the shape of the motor, but the differences between IP44,IP55 and IP56 motors may not necessarily be seen by non-professionals, and some motor manufacturers will also deal with customers by changing nameplate data.

According to the requirements of shaft surface oil seal involved in different protection grade motors, we can distinguish from intuitionistic judgment. The motor of IP23 and IP44 protection grade has no shaft surface oil seal in shaft extension position, while the motor of IP54 and above protection grade adopts suitable oil seal device in bearing outer cover according to different protection grade requirements. For the oil seal device, some motor manufacturers are placed on the outside of the bearing cover bearing, while others are placed on the inside position of the bearing outer cover shaft hole, especially for the skeleton oil seal used when the protection level is high, the inner position placed by many motor manufacturers can not be seen from the appearance of the motor. the difference with other motors.