What are the things that must be paid attention to in the grinding process of the commutator

Update:22 Aug 2022

The commutation device is a part of the DC permanent magnet series excitation motor in order to allow the motor to continue to roll. Structurally, the dc motor commutator is a circle surrounded by several contact pieces, which are connected to each contact on the rotor respectively. The two electrodes connected to the outside are called brushes, and only two of them are contacted at the same time.
After a long-term operation of the DC motor, due to poor commutation, unreasonable brush arrangement and inappropriate brush material, streaks, regular burns, surface pitting and uneven wear often appear on the surface of the commutation equipment. The waviness, at this time, it is generally necessary to use a special grinding stone to polish the reversing equipment. When in use, the grinding stone should be glued to the base of the grinding tool with a handle. The speed of the reversing equipment should be about 10m/s during grinding, and the sand and stone should be stably pressed on the reversing equipment with both hands. The holding pressure should not be too large, and it has been polished until the surface burn marks and channels are no longer visible. After the grinding stone is finished, use a finer-grained emery cloth to surround the wood block, and use the same method to polish it again. For high-demand reversing equipment, canvas should also be used instead of fine emery cloth, and then polished again.
It is necessary to pay attention: Do not use emery cloth to polish the commutator, because the emery particles are embedded in the surface of the commutator, which can scratch the surface of the commutator and the brush, form a fine channel on the surface, and affect the formation of the oxide film; when the commutator is When the surface burn is severe, the channel is deep and the wave degree exceeds 0.5mm, grinding the commutator will not achieve the effect of improving the surface condition of the commutator, and the surface of the commutator should be turned.

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