Nilfisk-ALTO SR1800C B-D - Manual (Page 67)

USER MANUAL
33014817(2)2006-06 A 17
Drive direct current motor (SR 1800C B)
Maintenance
Every 150
hours
Every 200
hours
Every 400
hours
Every 6
months Every
year
Every time
a check is
carried out
Commutator
Ensure that the surface along which the carbon
brushes slide is covered with an even, shiny,
transparent light grey film.
Check that there are no black marks or burns
between the commutator segments and on the
commutator outer crown
Ensure that the commutator surface is not lined,
deeply grooved or burnt on the segment in or out
edges.
Check that the brooms have not grooved the
commutator surface and that the insulating mica
does not protrude from the copper segment.
Check that the commutator is clean and that there
are no burns on the segments; if necessary, clean
the commutator as described.
Check eccentricity.
Clean the commutator with special rubber sticks. If
necessary, clean between the segments.
Carbon
brushes
Check the carbon brush for wear. It is worn out
when more than half of its total length has been
consumed. Check that it slides freely in the brush
holder, that it is pressed correctly by the spring and
that the spring is still elastic.
Ensure that the surface along which the carbon
brushes slide is evenly and highly polished and
that any lines or porosity are extremely small and
of similar dimensions.
Check the wire for wear and ensure that the
connection terminals are well tightened.
Ensure that there are no big lines, deep grooves,
craters, burns or splinters on the carbon brush
edge and that all the carbon brushes are worn in
the same way.
Check the housing for wear and clearance.
Brushes usually last from 6 months to 1 year,
depending on use.
Check the carbon brush and coupling pressure.
When the warning light turns on, the carbon
brushes need to be replaced, even if 300 hours
have not been reached.
Terminals
Check that supply bolt nuts are well tightened and
that the insulating materials are in good condition.
Fan
Ensure that air intakes are not clogged and that the
fan turns freely.
Bearings
Check the temperature and the vibration and noise
degree.
Insulation
Use a megger, especially when the environment is
wet, to check the insulation value: it should never
be less than 2 MOhm.
Screws
Check that the screws are not loose.
Check that there are no faulty contacts in the
electrical connections which could lead to local
overheating.
Windings
General cleaning. Check that the insulation to
ground is less than 2 MOhm.