What is a vertical motor? What are the common failures?

What is a vertical motor? What are the common failures?

　　A vertical motor is a motor with the output shaft axis perpendicular to the chassis or variable speed mechanism. Its distinguishing feature is that the mounting holes are located in the center of the output shaft and are equally spaced around it. The vertical motor is arranged vertically on the driven machine, and the motor shaft also drives the machine vertically. It is widely used in industrial production, such as vertical water pump, vertical lathe, etc. Vertical motor is a motor whose motor output shaft axis is perpendicular to the chassis or variable speed mechanism. Its prominent feature is that the mounting holes are located in the center of the output shaft and are equally spaced around. During the use of the motor, the motor or bearing temperature is often too high and does not meet the requirements of equipment use due to the selection of bearings and the matching of parts and bearings with hidden problems.

　　Vertical motor common failures

　　1、 Thrust tile burning: thrust tile is the key component of large vertical motor. According to statistics, the thrust tile burning failure accounts for about 40% of the pump group equipment failure. The root cause is that the oil film between the thrust tile and the mirror plate is damaged, frictional heat increases rapidly, and the temperature of the shaft tile surface exceeds the melting point of the pasteurized alloy on the surface of the shaft tile, resulting in combustion loss.

　　The solution mainly includes: increasing the area of the existing pasteurized alloy thrust tile, improving the overload capacity of the thrust tile, using a hydraulic jacking device (opening a hole in the center of the thrust tile and injecting high-pressure oil to promote the formation of the oil film), ensuring the machining accuracy of the contact surface of the thrust head and thrust tile, and improving the cooling capacity of the water cooler in the oil tank.

　　2, bearing chamber oil leakage: most large vertical water pump motors are equipped with thin oil lubrication thrust bearings. Bearing chamber oil shedding occurs frequently, which seriously affects the stable and safe operation of the unit. The problem of oil shedding in the bearing chamber is mainly caused by negative pressure and turbulence. When the axial fan rotates while the motor is running, the negative pressure formed inside the motor causes negative pressure. Oil and gas in the motor bearing chamber are sucked out by the negative pressure and condense into oil droplets. The oil easily flows into the motor rotor through the top edge of the oil baffle. Turbulence occurs because the motor drives the thrust head of the thrust bearing to rotate at high speed and the lubricant agitates rapidly and the oil flow becomes turbulent and milky with a large mixture of oil and gas, which enters the motor through the gap between the oil retaining cylinder and the spindle.

　　A feasible way to solve the negative pressure is to increase the height of the oil baffle in the thrust bearing and add floating seals on the outside of the oil baffle, which can greatly reduce the oil and gas entering the rotor. At the same time, add an air filter to the bearing oil tank to balance the air pressure

　　Conventional thrust bearings generally use fan-shaped thrust shingles. This type of shaft shingle has a wide range of applications. Most of the vertical water pump thrust bearings operating in China use this type of thrust bearing. In addition, large, medium or very large generating units in the hydropower industry have enormous size and weight. Under the premise of meeting the unit pressure requirements on the surface of the shaft shingles, the thrust shingles are fan-shaped, with large areas, narrow shapes and large numbers of shingles. However, the larger the area of traditional fan-shaped thrust shingles, the more difficult it is to control the deformation and the higher the operating temperature may be. In practice, it is difficult to control the deformation within a good range.

　　When using fan tiles, round tiles are used to eliminate the edge effect. In addition, the thermal and elastic deformation of round tiles is easy to calculate, which facilitates the optimal design of tiles to select a more reasonable ratio between tile diameter and its thickness. Round thrust tiles can automatically adjust the tilt angle during operation, providing better adjustment than traditional tiltable tiles, which have a greater load-bearing capacity than tiltable tiles, while being cheaper to manufacture. In particular, the round thrust tile reduces the requirement of installation precision, which largely avoids the failure of tile combustion and mechanical vibration caused by installation and makes installation and use more convenient.