Electrical System
363
CHARGING SySTEM
The charging system is an electrical power generating system that provides electrical power to all of the
electrical systems and also charges the batteries. The charging system power output is provided by the
alternator and controlled by the voltage regulator. The batteries do not supply any power to the electrical
system when the engine is running and the alternator is operating.
Alternator
The alternator is belt driven by the engine and is rated at 270 amperes when operating at 5,000 alternator
rpm and 170 amperes when operating at 1,800 alternator rpm.
The standard alternator is a totally enclosed, brushless unit, in which all the current carrying members,
windings, built-in diodes, and field coils are stationary. The only movable part is the rotor, which is
mounted on bearings in the alternator frame. An external oil line is connected from the oil supply tee at
the diode end frame to the drive end frame to supply oil to the front bearing. A continuous supply of oil
circulates through the alternator to provide both lubrication of the bearings and cooling of the alternator.
The oil drains back into the engine crankcase through external tubing.
The alternator has four ter
minals: the POS output terminal, the positive and negative field terminals,
and the “RELAY” terminal. The POS output terminal is connected to the vehicle circuits through a fuse
in the engine compartment. The positive field terminal (F1) is connected to the voltage regulator. The
ground field terminal (F2) is grounded to the diode end frame on the alternator. The “RELAY” terminal
is connected to a fuse and the No-Charge Relay that operates the No-charge warning light on the indica-
tor lamp strip.
Voltage Regulator
The voltage regulator is mounted on the right side of the engine compartment on the battery fuse panel.
The purpose of the voltage regulator is to limit the alternator output voltage to a preset value. This as-
sures the proper voltage to charge the batteries and safely operate the electrical components. The voltage
regulator model installed in the coach operates with solid state components. A potentiometer is provided
to adjust the alternator output voltage. No other adjustments or repairs are possible. Once the regulator
is properly adjusted, the alternator voltage remains constant regardless of changes in alternator speed or
output.
Operation
See Figure 9-
10
. The voltage regulator supplies a low current DC voltage to the alternator field termi
-
nals, causing the field windings to form a magnetic field. The rotor, rotating in this field, produces a
3-phase alternating current (thus the name alternator) in the stator windings. This alternating current is
rectified into direct current by the diode configuration and outputted at the POS Terminal. The voltage
regulator maintains the alternator output voltage at approximately 28 volts by regulating the amount of
current sent to the alternator field coils.
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...