Electrical System
364
Figure 9-10, Alternator Schematic
FIELD
TERMINAL
"F1" (+)
FIELD
TERMINAL
"F2" (-)
POSITIVE
TERMINAL
RELAY
TERMINAL
RECTIFIERS
STATOR
WINDINGS
FIELD
WINDINGS
20-800-57
Alternator Mounting
The belt driven alternator is mounted at the rear of the engine on a mounting cradle. A polyvee belt
drives the alternator pulley from an accessory pulley on the engine. Drive belt tension is automatically
maintained by spring tension on the idler pulley. See the
Engine
chapter for belt changing instructions.
Alternator Precautions
To prevent damaging the electrical system, observe the following precautions when performing service
operations on the system.
1. The electrical system is NEGATIVE GROUND. Connecting the batteries or a battery charger
with the positive terminal grounded will endanger the alternator diodes and vehicle wiring. The
high current flow may result in a burned wiring harness and burned open diodes.
2. Never operate the alternator on an open circuit (field terminal connected and output terminal dis
-
connected). With no battery or electrical load in the circuit (open circuit) the alternator can build
up excessively high voltage. Be sure all connections in the charging circuit are secure.
3. Current is supplied to the alternator output (positive) terminal whenever the batteries are con-
nected. If work is to be done near the alternator, turn the battery disconnect switch to the “OFF”
position to prevent accidental grounding of the alternator output terminal.
4. Do not ground the alternator field “F1” (+) terminal. Grounding this terminal will cause the 24
volt regulator circuit to shut off until the ground is removed.
5.
Do not test the alternator using the “full fielding” method.
Doing so can cause severe electri-
cal damage to electrical equipment in the vehicle!
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...