Maintenance & Troubleshooting 3-5
MN605
Carbon Brushes For Special Operating Conditions
Sometimes, there are problems if motor operation requires a different design or grade of carbon brush
than what was installed when the motor was built. These special operating conditions include long periods
of operation with loads that are significantly greater or less than rated load capacity. Also, operation in in
the presence of certain chemicals, or extreme temperature and humidity can degrade brush performance.
Generally, poor brush life or commutator wear can occur if one or more of the above conditions exist. The
brush used doesn’t match the operating conditions.
Baldor offers optional brush grades for the above conditions and has replacement brushes available to
retrofit motors. Contact your local Baldor District Office or an Authorized Baldor Service Center for
technical assistance.
Do not change brush grades or the number of brushes per pole. Doing so may void the warranty and
make the motor unsafe. Contact your local Baldor district office or an authorized Baldor service center for
technical assistance.
Authorized Service
Baldor catalog 505 (and the Baldor CD
−
ROM) lists service shops authorized to service Baldor
DC motors. Contact your local Baldor District Office for more information.
Humidity And Brush Wear
This curve represents 2 grains of water per cubic foot of dry air or 4.6 grams per cubic
meter of dry air.
Zone of Safe Brush Operation
110
100
90
80
70
60
50
40
30
45
40
35
30
25
20
15
10
5
0
10
20
30
40
50
60
70
80
90 100
Percent Relative Humidity
Temperature Degrees F
Temperature Degrees C
Danger Zone
Too Low Humidity
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