National Crane 600H, Service Manual

Page: 57 / 232

10
3
NATIONAL CRANE
08-19-2022 Control # 092-13
3-3
600H ELECTRIC SYSTEM
ensure that the pins and sockets are properly seated and
engaged. If the pins and sockets show any signs of
corrosion, use a good quality electrical contact cleaner or
fine sandpaper to clean them. When the pins or sockets
show signs of arcing or burning, it may be necessary to
replace them.
Damaged connectors need to be cut off the wire and this
may make the wire too short for the new connector to make
proper contact. The wire needs to have some slack after the
connector is put together. Splice a wire of the same size to
the cut wire. Use solder to ensure a good connection and
shrink tube to insulate the splice. Crimp the new connector
on the spliced wire.
RCL SYSTEM DESCRIPTION
The RCL monitors crane operation and alerts the operator of
an impending tipping condition and disables the crane
functions. A RCL key switch is located behind a door on the
drivers side of the operators console. Turn the key switch ON
and press the RCL momentary override switch on the
operators console to override the RCL and operate the
crane.
The RCL is powered by a 12V input from the truck battery
through a 15 Amp fuse. A toggle with in the truck cab turns
the RCL system ON and a light next to the switch indicates
when the RCL is active. The RCL memory always has power
supplied by the truck battery even when the truck ignition is
in the OFF position.
NOTE: Consult the RCL manual in the event of an RCL
malfunction.
ANTI-TWO BLOCK SYSTEM DESCRIPTION
The anti-two-block system (ATB) on your National Crane
helps prevent cable damage by sensing when the end of the
hoist cable is near the boom tip and disables the functions
that cause a two block condition. Normal functioning is
restored by hoisting down or retracting boom until the
ATB weight is suspended freely. The ATB system is
incorporated into the crane RCL system.
ATB Wire Repair
The ATB cable runs from the ATB reel through the boom to
the boom tip (Figure 3-2). To replace the ATB cable:
• Retract the boom.
• Run a small diameter rod from the front of the boom to
the back.
• Attach the cable to the rod and pull the cable through the
boom and secure the ATB cable to the boom tip.
WARNING
Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state or federal regulations
anti-two-block reel
anti-two-block cable
FIGURE 3-2
REFERENCE ONLY