Service Manual

Table Of Contents
6. Service10-2019
111A062J683 (Issue 1) Copyright © 2019 Cummins Inc.
Alternator Heater
DANGER
Live Electrical Conductors
Live electrical conductors can cause serious injury or death by electric
shock and burns.
To prevent injury and before removing covers over electrical conductors,
isolate the generator set from all energy sources, remove stored energy and
use lock out/tag out safety procedures.
Power to the alternator heater is supplied from a separate AC source. The
alternator heater raises the air temperature around the windings to deter
condensation forming in humid conditions when the generator set is not operating.
Alternator Temperature Switch
The alternator temperature switch helps protect the generator set when unusual
conditions occur such as severe blockage of the air intake or air discharge panels.
The temperature switch is fastened to the lower stator through-bolt on the non-drive
end of the alternator and on the exhaust side of the enclosure near the brush block
maintenance panel. The temperature switch contacts are normally closed. The
switch contacts open at 197 210 °F (92 99 °C). If the switch contacts open, the
generator set control will turn off the generator set.
Sealed Bearings
Inspect sealed-for-life bearings periodically. Check for signs of wear, fretting or
other detrimental features. Damage to seals, grease leakage or discoloration of the
bearing races indicate that the bearing may be failing.
Brush Block/Slip Ring Service
1. Remove the brush block cover.
2. Disconnect the field leads from the brush block (F1, F2).
3. Remove the two mounting screws.
4. Withdraw the brush block from the alternator end bell.
5. Inspect the brush block:
a. If either brush is shorter than 11 mm (7/16 inch), binds in the brush block,
or is damaged in any way, replace the brush block assembly.
i. When re-installing the brush block, make sure to keep the brushes in
the retracted position by using a wire through the hole in the end of the
brush block. A new brush block assembly will come with this wire in
place.
ii. After bolting the brush block securely in place, remove the wire.