Vecr/Vecf Circuit Breakers; Multiplex Fuses; Relays - PREVOST H3-41 Maintenance Manual

2.6.3

VECR/VECF Circuit Breakers

Smaller circuit breakers are located in the VECF
and VECR in front
compartment respectively.
CIRCUIT BREAKERS
Wipers - VECF
CB48
front junction box
24V distribution - VECR
CB128
rear junction box
2.6.4 Electric
Breakers
MAXI 50 Amp manual reset CB
Each radiator or Charge Air Cooler electric fan
may be protected by a MAXI 50 amp single pole
thermal type breaker with manual reset. If
tripped, the circuit breaker remains open until it
is reset by pressing the reset button.
This type of circuit breaker inserts
in MAXI fuse blades mounting
style. Simply pull the circuit
breaker off the blade type mount
to replace.
FIGURE 4: ELECTRIC
BREAKER BOX
ELECTRIC FAN DRIVE 50 Amps CIRCUIT BREAKERS
ID Description
CB201 Charge Air Cooler fan #1 - Mo65
CB202 Charge Air Cooler fan #2 - Mo67
CB203 Radiator fan #3 - Mo68
CB204 Radiator fan #4 - Mo69
CB205 Radiator fan #5 - Mo70
CB206 Radiator fan #6 - Mo71
CB207 Radiator fan #7 - Mo72
CB208 Radiator fan #8 - Mo73
and rear electrical
20 A
30 A
Cooling Fan Circuit
COOLING FAN CIRCUIT
connector
1
2
3
4
5
6
7
8
PA1621 Maintenance Manual All Series | Revised Sept 2019
SECTION 06: ELECTRICAL
2.7

MULTIPLEX FUSES

The multiplex outputs are protected in current by
an internal "soft-fuse".
programmed specific
When an output is shorted, the current gets
above the limit and the soft-fuse intervenes to
turn the output OFF. The output stays OFF until
the "soft-fuse" is reset.
Turn the ignition key to the OFF position and
turn to the ON position again. This resets all
"soft-fuses".
There is also hardware fuses used to protect the
incoming power to the multiplex modules. These
fuses are located inside the VECF (Vehicle
Electrical Center Front) and VECR (Vehicle
Electrical Center Rear).
2.8

RELAYS

Relays are used to automatically energize or de-
energize a circuit from a remote location. The
relay draws a very low current to energize its
coil. Once the coil is energized, it develops a
magnetic field that pulls a switch arm closed or
open, to either energize or de-energize a given
component. As the control current required for
the coil is very low, the relay allows a remote
station to control a high energy circuit without
running great lengths of costly high capacity
cable, and also eliminates the need for high
amperage switches and heavy connectors.
86 coil
85 coil
30 common feed
87 normally open contact NO
87A normally closed contact NC
FIGURE 5: SINGLE POLE DOUBLE THROW RELAY
NOTE
Each relay is identified with "12V" or "24V"
printed on its casing in order to identify the
coil operating voltage.
Each output has
maximum amperage.
19