Motor mechanical troubleshooting Daquan! (Four)

27/07/2019

Seventh, how to check and clean the stator and rotor?

After the motor is disassembled and disassembled, the following checks and cleanings should be performed on the stator and rotor:

1. Clean the dust on the stator and rotor with compressed air or leather tiger.

2. The oil tower and dirt on the coil are wiped clean with a clean cloth, alcohol or carbon tetrachloride.

3. Clean the iron core, coil and commutator, etc., do not use metal tools to prevent damage to the insulation. Use a clean brush or a soft rag.

4. Check whether the iron core lamination is tight, whether there are any defects such as burrs and chamfers; whether the clamping bolts are symmetrically pressed, whether the chains, pins, etc. are loose; whether there are any debris in the ventilation ditch and the welding of the ventilation sheets is firm.

5. Check the insulation of the coil for air bubbles, peeling and damage; whether the binding wires, wedges and spacers of the coil are complete and tight, whether there is looseness, turbulence or protruding wedges.

6. Check whether the magnetic pole and the coil are fixed firmly, whether the insulation of the insulating bolt is good, whether the compensation coil of the extreme palm is tight and whether the connection is bent or short-circuited.

7. Check whether the balance block on the rotor is firm, with or without displacement and falling off.

8. Check whether the armature winding binding wire is firm, and whether the head cover, the lifting piece and the lead wire are damaged or poorly welded, and there is no conductive foreign matter between the slits.

9. Check the cage rotor copper strip (aluminum strip) for cracks, whether the welding with the end ring is firm, whether there are cracks or looseness, and whether the leads are damaged or broken.

10. In the above inspection, if problems are found, corresponding measures should be taken to repair them, and the damage should be replaced in time.

Eight, how to disassemble the bearing?

The rotating shaft of the motor is closely matched with the inner ring of the bearing. Usually, the inner ring of the bearing is pressed against the journal by pressing in, so that the inner ring of the bearing can rotate together with the rotating shaft when the motor is running. Therefore, disassembling the motor bearing is a cumbersome task.

Commonly used bearing disassembly methods are as follows:

1. Disassemble the bearing with a special puller

When disassembling with a special puller, place the foot of the puller on the inner ring of the bearing, but not on the outer ring to prevent the bearing from being damaged. The apex of the puller screw should be aligned with the center of the shaft. The puller should be parallel to the shaft. When the handle is rotated, the force should be uniform and the rotation should be slow to prevent the bearing from being pulled too quickly. In order to make the disassembly easy, some kerosene may be infiltrated between the inner ring of the bearing and the rotating shaft.

2, remove the bearing with a metal rod

When there is no special puller or is not suitable for disassembly with a puller, the metal rod can be placed on the inner ring of the bearing, and the metal rod is hammered by hand, and the bearing is slowly knocked out from the rotating shaft. In order to prevent bearing damage during tapping, the force should not be too violent. The two corresponding sides of the bearing should be beaten in turn, not only on one side, so that the bearing inner ring is evenly stressed.

3, placed on the cylinder to disassemble the bearing

Place the bearing on the cylinder, place two iron plates under the bearing inner ring, and rest the iron plate on a cylinder with an inner diameter slightly larger than the outer diameter of the shaft. In order to prevent the bending of the shaft and the deformation of the end, it is not possible to directly hit the end face of the shaft with a hammer. A hard wood board or a copper block should be placed on the end surface of the shaft, and then the board or the copper block is hit with a hammer. The point of impact when striking should be aligned with the center of the shaft, and the force should not be too violent. In order to prevent the rotor or the shaft from being damaged when the bearing is detached, some soft things should be placed at the bottom of the cylinder. In addition, when the bearing is gradually loosened, the tapping force should also be reduced.

4, heating method to disassemble the bearing

The method of disassembling the bearing by heating is to use the principle of thermal expansion and contraction to make the inner ring of the bearing expand and then remove it. It is suitable for situations where assembly tolerances are too tight or bearing oxidation is difficult to disassemble using the above methods. Before heating, in order to make the bearing and the rotating shaft produce a significant temperature difference and prevent heat dissipation, wrap the rotating shaft with a cloth soaked in cold water, then pour the oil heated to about 100 °C on the inner ring of the bearing, and remove the bearing. under.

5. Bearing removal method in the end cover hole

When the bearing outer ring and the motor end cover hole are tightly assembled, the outer ring of the bearing is left in the motor end cover hole after the end cover is removed. At this point, the end caps can be placed face up and placed smoothly on the two iron plates, taking care not to catch the bearings. Then, a metal rod with a diameter slightly smaller than the outer diameter of the bearing is placed on the bearing outer ring, and the bearing outer ring can be pushed out by slowly tapping the metal rod with a hammer.