Motor mechanical troubleshooting Daquan! (Three)

24/07/2019

Fifth, how to remove the end cap?

The end cap removal method of the motor is as follows:

1. In order to avoid mistakes during assembly, mark the joint between the casing and the end cover before removing the end cover.

2. Before removing the sliding bearing end cover, first release the grease (oil) and lift and tie the oil ring.

3. For the slip ring or commutator motor, remove or lift and tie the brush, and mark the position of the brush holder. Be careful not to damage the brush and lifting device when disassembling.

4. For motors with roller bearings on the load end, the non-load end should be removed first.

5. For general small motors, just remove the end cover on the fan side, first remove the screws on the end cover, and then pull out the rotor, end cover, bearing cover and fan together.

6. For large and medium-sized motors, because the rotor is heavy, the end covers must be removed. When removing the two-sided end cover, first loosen the upper cover screw, then loosen the lower cover screw, then uncover the upper cover, remove the upper tile after lifting, remove the oil ring, take off the lower tile, and remove the lower cover. For ease of assembly, load and non-load terminals should be marked for disassembly.

7. When removing the rolling bearing end cover, first remove the small cover, then remove the large cover screw and remove the large cover.

8. In order to prevent the stator and rotor from colliding with each other, the insulating paperboard should be placed in the air gap after removing the end cover.

9. The removed small parts should be stored in a special parts box, and each set of parts should be assembled as they are to facilitate the assembly.

Sixth, how to extract the rotor of the motor?

The rotor extraction method of the motor depends on the structure and weight of the rotor and the lifting equipment used at the repair site.

There are four common methods for extracting the rotor of a motor:

1. The rotor of the small motor can be taken out from the stator directly by hand. However, care should be taken not to scratch the core and windings.

2. When the rotor of the motor is larger than the inner bore of the stator, the rotor should be withdrawn from the side of the fan; for motors with slip rings or commutators, the rotor should be withdrawn from the side of the slip ring or commutator. The fan, slip ring or commutator does not have to be removed.

3. If the rotor of the motor is heavy and the shaft extension is long, the crane can be used to extract the rotor. During operation, the wire rope of the crane is used to hang the rotating shaft, and the center of gravity of the rotor is slowly moved to the outside of the stator, and then the moving end is placed on the bracket with the insulating cardboard. At this time, the crane wire rope is changed to the center of gravity of the rotor, and the rotor can be lifted. When the rotor shaft of the motor is short, the center of gravity of the rotor cannot be removed from the outside of the stator. A steel pipe of appropriate length (false shaft) can be placed on the shaft.

Care must be taken when pumping the rotor to prevent the stator winding from being scratched. If necessary, an insulating cardboard can be placed on the end of the coil for protection.


4. For a rotor that cannot be fitted with a false shaft, it can be extracted by two-draw rotor method. That is, the rotor is first drawn by a double hook, and after a certain length is extracted, the extracted rotor portion is placed on the height-adjustable bracket, and the portion in the stator is temporarily supported on the stator core. After that, the rotor is lifted and pulled out.

After the rotor of the motor is drawn out, the coil, iron core, wedge, and end banding should be inspected in time for any bruises. If there is a damaged part, it should be repaired in time.