DC motor - Siemens, s.r.o.

6.1.9 Maintenance of the commutator
Cleaning the commutator
Maintenance
Oil, grease and/or dust must be cleaned from the commutator with a non-linting
cloth. The slots between the commutator segments must be cleaned with a
suitable small wooden stick or glass brush.
Note
Unclean slots can cause sparking or arcing on the commutator.
Reworking the commutator after ribbing/threading
Slight ribbing or light burn marks have no effect on the operational reliability of the
motor. Reworking of the commutator is only necessary when scorching or grooves
are apparent and/or when the commutator is out of round.
The commutator can be ground in the installed state with a commutator grinder of
average grain size, grain no. 80 (210 - 177 µm).
To do this, lift a large proportion of the brushes and run the motor at a speed of
approx. 600 rpm. Bring the grinder into contact with the brush holder.
Afterwards remove the grinding dust with dry, oil-free compressed air.
If necessary deburr the segment edges.
If it is seriously out of round, the rotor must be removed and the commutator must
be skimmed on a lathe. The commutator can be skimmed down to the smallest
permissible diameter (dmin) according to the table below.
Table 6-3 Commutator reworking – minimum diameter
Shaft height Nominal diameter
dN (mm)
1G.5/1H.5
500 560 546
630 720 706
1G.6/1H.6
180 190 184
200 210 202
225 240 232
250 265 257
280 300 292
1G.7/1H.7
355 350 340
400 350 340
Minimum diameter
dmin (mm)
SIEMENS AG T61160347010001 (DMHO V9)
Operating instructions 1GG6286-0NA4.-1VV1-Z 6-7