6-13
Copyright 2017 Cummins Inc.
ALTERNATOR DISASSEMBLY
The following procedures provide information for
removal and reassembly of the alternator PMG ex-
citer, control housing, and stator/rotor assemblies.
Be sure to read through this section first, before per-
forming procedures listed, to determine the steps
most appropriate for the service attention required.
Two types of alternators (P7 or HC6) are used with
these generator set models. The major difference
between these two alternators is the lifting eye loca-
tions on the alternator and the type of control hous-
ing. The control housing for the HC6 alternator is
shown in Figure 6-7 and the control housing for the
P7 alternator is shown in Figure 6-8. In the following
procedures, if the step only applies to a particular
control housing or alternator, it will be noted at the
beginning of the step (e.g., HC6 control housing, P7
alternator, etc.)
Permanent Magnet (PMG) Removal
WARNING
Ignition of explosive battery gases
can cause severe personal injury or death. Arc-
ing at battery terminals, light switch or other
equipment, flame, pilot lights and sparks can ig-
nite battery gas. Do not smoke, or switch
trouble light ON or OFF near battery. Discharge
static electricity from body before touching bat-
teries by first touching a grounded metal sur-
face.
Ventilate battery area before working on or near
battery—Wear goggles—Stop generator set
and disconnect charger before disconnecting
battery cables—Disconnect negative (−) cable
first and reconnect last.
CAUTION
Disconnect battery charger from AC
source before disconnecting battery cables.
Otherwise, disconnecting cables can result in
voltage spikes damaging to DC control circuits
of the set.
WARNING
Accidental starting of the generator
set can cause severe personal injury or death.
Prevent accidental starting by disconnecting
the negative (−) cable from the battery terminal.
1. Disconnect the negative (-) battery cable to
prevent accidental starting of the generator set
while servicing.
2. HC6 Control Housing: Remove the control
housing grille and access covers (see Figure
6-7).
3. Remove the three M5X12mm capscrews and
lockwashers from the PMG cover, and remove
cover.
4. Disconnect the PMG wiring harness connector.
5. Remove the four bolts and clamps retaining the
exciter stator housing to the endbracket.
6. Tap the stator housing out of its spigot, and
carefully remove from alternator endbracket.
The highly magnetic rotor will attract the stator
core; care must be taken to avoid any contact
which may damage the windings.
7. Remove the hex head through-bolt from the ro-
tor shaft and firmly pull the complete rotor as-
sembly from its location. Keep the rotor clean
by avoiding contact with metal dust or particles.
CAUTION
The rotor assembly must not be
dismantled, or the magnetic properties will
be destroyed.
Permanent Magnet (PMG) Installation
1. Install the complete rotor assembly to the end
of the main rotor shaft using the hex head
through-bolt. Keep the rotor clean by avoiding
contact with metal dust or particles.
2. Carefully locate the stator housing to position
on the alternator endbracket. Fasten in place
using the 4 bolts and clamps, and tighten se-
curely.
The highly magnetic rotor will attract the stator
core, care must be taken to avoid any contact
which may damage the windings.
3. Connect the PMG wiring harness connector.
4. Install the PMG assembly cover using the three
M5x12mm capscrews and lockwashers, and
tighten securely.
5. HC6 Control Housing: Install the control hous-
ing grille and access covers (see Figure 6-7).
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