DC motor - Siemens, s.r.o.

6.1.6 Checking brushes
Brush movement
Brush height
Maintenance
In normal operation the carbon brushes must rest properly against the commutator
and move easily in the brush boxes. The freedom of movement must be checked
at regular intervals.
Note
The permissible residual brush height is approximately 16 mm. The wear limit for
the carbon brushes is shown by a line mark or by the lower edge of the
manufacturer's name.
On motors with brush-height monitoring, the shortest brush opens a microswitch
when the brush height is still at least 2 mm more than the minimum brush height. In
normal operation the motor can then still be used for a further 500-1000 operating
hours.
Caution
Worn carbon brush must be replaced without delay.
[ID 574]
6.1.7 Replacing the carbon brushes
Removing worn carbon brushes
Normally all brush holders are accessible via the open covers or louvered plates of
the bearing end shield at the N-end. In addition, the brush rocker can be rotated to
the most convenient position after the locking screws accessible from the inside
have been loosened. If necessary the cables should be disconnected from the
brush rocker first.
Fitting new carbon brushes
New carbon brushes must be bedded in with emery cloth (not too coarse) as
follows:
•= Use double-sided adhesive tape to attach a strip of emery cloth which is as
wide as the length of the commutator contact surface and as long as the
commutator circumference to the commutator.
•= Insert the new carbon brushes.
•= Slowly turn the commutator by hand according to the correct direction of
rotation (in exceptional cases pull through emery cloth by hand under the
brushes).
SIEMENS AG T61160347010001 (DMHO V9)
Operating instructions 1GG6286-0NA4.-1VV1-Z 6-5