Maekawa Compressor Repair Report 37H1410SSC

Thread Content

1. Unit overview: Compressor model: 37H1410SSC; Serial number: 9182408. Task: Disassemble and inspect the compressor.
2. Repair process:
2.1 Used a megohmmeter to check the motor’s insulation; the values were normal both between phases and relative to ground.
2.2 The motor was disassembled; the rotor exhibited severe scrubbing, with the back surface showing discoloration due to high temperatures. The corresponding parts of the stator were dirty and covered in debris.
2.3 The rotor could be rotated manually fairly easily, but there were slight sticking points. When the rotor was pulled out, the drive shaft showed significant discoloration due to high temperatures.
2.4 The oil filter was removed.
2.5 The exhaust silencer, as well as the bearing caps and rotor chamber on the suction side of the upper rotor, were taken off. The upper rotor showed mild wear, as did its internal cavity.
2.6 Both the upper and lower rotors were pulled out together; it was found that the exhaust clearance of the lower male rotor was as high as 200 microns, which is far above the normal range. The corresponding suction end face was severely worn due to the movement of the rotor.
2.7 All four rotors were disassembled.
2.8 The bearings and air seals were removed; the balls in the bearing on the suction side of the lower male rotor were severely worn.
3. Issues identified and requiring repair:
3.1 The rotor suffered severe scrubbing wear and needed to be repaired and balanced again.
3.2 The locking mechanism of the lower male rotor was loose, resulting in an excessive exhaust clearance and movement of the main shaft. This caused severe wear on the rotor end faces and the suction seat, as well as damage to the bearings on the suction side. This was the main reason for the high noise level during compressor operation. The lower-stage male rotor needs to be repaired and subjected to a balancing test. 3.3 The balls in several bearings as well as the surfaces of their inner rings are worn out, exceeding the normal service life of these bearings; therefore, all of them must be replaced. 3.4 The sealing gaskets and air seals need to be replaced as well. 3.5 The inner wall of the water-cooled motor needs to be cleaned. 4. Analysis of the reasons for compressor damage: 4.1 Loosening of the locking mechanism of the lower-stage male rotor leads to wear on the suction end face during the operation of the main rotor, as well as high current and high temperatures during compressor operation. 4.2 Bearings that have exceeded their service life contribute to abnormal vibrations and noise during compressor operation, and they also cause the motor rotor to sweep