ELECTRIC SYSTEM
CD5515-2/YB5515-2 SERVICE MANUAL
3-20
Published 1-20-2017, Control# 483-02
ACCESSORY CIRCUITS
Anti-Double Blocking System
General
This mechanism (Figure 3-10) prevents the hook block from
being pulled into the boom head during extension of the
booms and during hoist operation. When the hook block
actuates the limit switch on the boom head, oil flow to the
telescope cylinder, lift cylinder and hoist motor is stopped. An
alarm is activated to give a warning to the operator in all
cases. To move the hook block away from the boom head,
the operator must retract the boom, raise the boom or lower
the hoist.
Circuit Description
See the wiring diagrams in
Schematics/Wiring Diagrams
.
Power is made available through a 25 amp fuse to the circuit
relay under the console in the cab and to the limit switch on
the boom head. When the hook block reaches the upper
limit, the limit switch closes, energizing the relay. The
energized relay activates the three anti-double blocking
solenoid valves in the lift, telescope and hoist circuits.
Electric Swivel
An electrical swivel is installed at the center of the mast
rotation. The swivel gives electric current continuity through
full rotation of the mast.
Rated Capacity Limiter (RCL) System
Description
The rated capacity limiter (RCL) is a length, load, angle,
radius, lifting capacity and anti-double block indicator. A
display in the cab provides information to assist the operator
in operating the crane.
The Wylie I4500 system, available as a CE option, can be
set with limits by the operator to warn of approach into
undesired areas of angle, length or height.
For more information on the RCL system, see the Owner’s
Manual furnished with the crane.
See wiring diagram in
Schematics/Wiring Diagrams
.
Optional Engine Shutdown
General Description
Cran es ca n be f urn is h ed wit h an a ut om at ic en gine
shutdown, to protect the engine when the engine oil pressure
is too low or the engine water temperature is too high. The
electrical circuit includes a mag relay switch located behind
the cab dash panel, two diodes in the instrument panel wire
harness, the engine water temperature and oil pressure
senders, and the fuel shut off valve.
Circuit Function
When the engine oil pressure drops below a safe operating
pressure or the water temperature rises above a safe
operating temperature, the sending unit sends a signal to the
indicator light, illuminating the light. It also, sends a signal to
the mag relay switch under the dash panel. Both senders are
connected to the “S” terminal of the relay. To prevent current
from one sender (oil pressure), illuminating the other
indicator light (water temperature) the circuit has two diodes
installed, which allow current to travel in one direction only.
The relay is activated and cuts current from the “NC” terminal
to the fuel shut off valve, closing the valve and shutting off
the engine.
Heater
The heater is a hot water heater and is connected into the
cooling system of the engine. An electric blower pushes air
through the heater core and into the cab. A defroster fan
blows air onto the windshield.
See the electrical wiring diagrams in
Schematics/Wiring
Diagrams
. Power is available through a 20 amp fuse to the
heater/defroster switch in the instrument panel when the
ignition switch is in the ON position. The switch is a three
position switch (HI, LO and OFF).
FIGURE 3-10
Reference Only
