Caution: This document contains mixed page sizes ... - Cummins Onan

GENERATOR SERVICE
WARNING Accidental or remote starting can
cause severe personal injury or death. Before
removing a housing panel or access door, disconnect
the negative (−) cable at the battery to
prevent the engine from starting.
Brushes and Slip Rings
Access: Remove the brush block access cover
(Figure 4-2) for access to the brush block assembly
and slip rings.
Checking for Wear: Check brush wear by marking
off a piece of wire at 1 inch (25 mm) and inserting it
into each of the two holes in the top of the brush
block from which the pig tails exit. Replace the brush
if the wire can be inserted more than 1 inch (25 mm).
(Make sure the wire rests on top of the brush and not
on part of the spring.)
Cleaning Up Slip Rings: If the slip rings are
grooved or pitted, try cleaning them up with a commutator
stone while cranking the engine. (Connect
the starter motor directly to a battery and the starter
solenoid to a remote start switch.) The rotor will
have to be removed if the slip ring assembly has to
be replaced.
Replacing Brush Block: When replacing the brush
block assembly, center the brushes on the slip rings
before tightening the two mounting screws. Make
sure to reconnect the lead marked F1 to the outboard
brush and the lead marked F2 to the inboard
brush.
BRUSH
LEAD
TERMINAL
FIGURE 10-2. BRUSH BLOCK ASSEMBLY
10-4