3-10 Published 08/16/19 Control # 112-05
ELECTRIC SYSTEM 500E2 SERVICE MANUAL
16. Disconnect hand control and store in truck, (If equipped
with hard wire remotes).
17. Start truck from inside of cab.
18. Stow outriggers.
19. Disengage P.T.O.
Hydraulic System Description
Solenoid Valve Assembly
Flow Control Valve in Inlet Section
1. Electrically controlled priority flow control valve which
can be remotely actuated to control the amount of oil
flow from the inlet to the bypass or the regulated ports.
a. Oil supply of 5 - 18 GPM is pumped to inlet port.
b. With electrical voltage up to 2 volts on the valve coil,
0 GPM of inlet oil is directed to the solenoid valve
sections and the remaining oil goes through the
bypass port and into the manual control valve, then
back to tank.
c. As voltage increases linearly from 2 to 9 volts, there
is a resulting linear increase of oil flow to the
solenoid sections to 18 GPM maximum. Any
remaining oil is directed back to tank through the
bypass port.
Solenoid Valve Sections
2. An electrically actuated directional control valve which
receives oil from the regulated port of the flow control
valve and directs it to the various crane functions.
a. When 12 VDC power is applied to any of the electro-
magnetic coils on the valve, the resulting force
pushes a spring centered spool from its neutral
position to allow oil flow out the work port opposite
the energized coil.
b. Oil flow through the solenoid valve is then increased
and decreased at the flow control valve to get
desired crane operating speeds.
3. Pressure relief valve (part of solenoid valve) in inlet
section.
a. Protects remote control hydraulic circuit from over
pressurization. Must be set to match crane manual
system pressure.
Shuttle Valve
Biased shuttle valves are located in the turn and hoist
functions on units equipped with remote hoist operation.
They block the open oil path through the main control valve
during remote operation.
Service and Maintenance
Follow the procedures outlined in the Service and
Maintenance Section of the Owner Manual to maintain
proper crane operation. The following procedure and
intervals represent additional required maintenance for a
crane equipped with a remote control option.
Initial Start Up
The return line oil filter cartridge should be changed after four
hours of operation and then again at 12 hours of operation.
After this initial break in period, normal maintenance
procedures found in the crane Service and Maintenance
Section of this book can be followed.
Troubleshooting, Repair and Replacement
A few of the remote control components can be repaired, all
can be replaced. The following is a list of these items and
recommended method of repair or replacement.
Circuit Breaker
There are two automatic resetting breakers in the system,
one 15 amp under the hood that protects the entire system
and a 10 amp on the frame that protects the hand control. If a
breaker is opening, it is an indication that there is a short
circuit somewhere in the system. It will generally stay open
from 30-60 seconds.
Relays
Three 12 VDC, normally open, automotive type relays are
installed under the truck hood on the ignition start and throttle
advance circuits. One automotive type relay is installed in the
control console on the HCA-RCL override circuit. They are
used so that current through the hand control does not
become excessive. These relays will occasionally fail from
physical damage, corrosion or excessive current through the
relay. Failure is evident when the relay will not close as
power is applied to the pilot terminal or will not open when
power is removed from the pilot terminal. These relays
cannot be repaired and must be replaced.
Solenoid Valve
If the solenoid valve is inoperative, it is generally because of:
• Contamination in the valve.
• Not enough electrical power to operate solenoids.
The valve can be disassembled and cleaned when
contamination is suspected. If voltage drops below 10.5 V at
the solenoid coil, the solenoids may not operate. Defective
electrical equipment on the truck will generally cause this low
voltage condition. Check the truck battery, voltage regulator
and generator (alternator) in this case.
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