Manitowoc National Crane NBT40 Series, Service Manual

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ELECTRIC SYSTEM NBT40 SERVICE MANUAL
3-2
Published 8-01-2017 Control # 287-11
service software and connection cable are available through
Crane Care to those service technicians who have attended
the Grove New Technology training course.
Troubleshooting the Electrical Swivel
Many crane component electrical troubles can be traced to
the electrical swivel. Troubles common to the swivel are
improper mounting, foreign material between the brushes
and slip rings, worn brushes, improper spring tension on the
brush assembly, and loose setscrews on the slip ring
assembly. Refer to the electrical schematic and wiring
diagram for slip ring connections and amperages.
Ignition Switch
There are two ignition switches on the crane. One is in the
truck cab and the other one is on the crane cab console.
Only one switch at a time can be energized.
NOTE: If one switch does not engage the truck starter,
check and make sure the other switch is OFF.
When the crane ignition switch at
the operators station is set to
RUN and the PTO engaged, the
throttle pedal in the operators
station overrides the truck cab
throttle, the RCL system is powered, and the crane functions
can be activated. The outrigger controls are disabled when
the crane function power switch is ON.
RCL SYSTEM DESCRIPTION
The RCL monitors crane operation and alerts the operator of
stability or structural limits based on the load chart. The
crane functions that worsen the condition (hoist up, boom
down, telescope out) are disabled. A RCL override key
switch is located behind the operator’s seat. Turn the key
switch ON to override the RCL. 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.
RCL & ATB System Description
The anti-two-block system (ATB) is part of the RCL system
that helps prevent damage to the hoist cable 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.
The boom ATB/RCL cable (1, Figure 3-1) runs from the ATB
reel (2) through the boom and to the ATB switch assembly
(4). The ATB switch assembly cable is attached to the anti-
two block weight (5).
The the RCL cable (3, Figure 3-1) runs from the bottom of
the reel (2) to the end of the boom, then splits, with one end
running down through the turret to the boom lift cylinder
pressure transducer (6) and the other end to the cab
operator’s console.
Two hydraulic hoses (7) run from the pressure transducer (6)
to the lift cylinder holding valve.
To re place t he ATB/RCL ( 1) a nd th e RCL c ab le (3)
disconnect the cable at the anti-two block switch (4), cab
operator’s console and the cylinder pressure transducer (6)
and then remove the cable from the reel (2).
WARNING
Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state or federal regulations
Reference Only