99903514: TELESCOPIC CRANE: 1-11 SECTION 1: OPERATION
1-8: CRANE CAPACITY ALERT SYSTEM
(ELECTRICALLY OPERATED)
IMT provides an electrically operated capacity
alert system on all of its field service, telescop-
ing, stick-boom cranes. This system is de-
signed to prevent loads from being lifted which
exceed the rated capacity of the crane.
The capacity alert system consists of a pres-
sure switch mounted on the lift side of the lower
boom cylinder which senses hydraulic pres-
sure. It is connected electrically to the lift side of
the winch, the extend side of the extension
boom, and the down side of the lower boom.
If an operator attempts to lift a load which
exceeds the rated capacity of the crane, the
capacity alert system will be activated. When
activated, it will prevent the winch from lifting,
the extension boom from extending, and the
lower boom from being lowered.
To resume operation of the crane when the
capacity alert system is activated, the winch
may be lowered or the extension boom re-
tracted. Being able to lower the winch will give
the operator the opportunity to reevaluate the
load and adjust it. Retracting the extension
boom will move the load closer to the centerline
of rotation and within acceptable limits of load
capacity.
It is important that this system be maintained in
good operating condition at all times. Wiring
should be checked on a regular basis for loose
connections, corrosion and broken wires. The
manifold should be checked for leakage from its
o-ring seal. The pressure switch is available
through IMT and its distributors and easily
replaced.
See Figure A-12 for general electrical wiring
reference and refer to your particular crane
manual for specific information on parts and
wiring.
Figure A-12: General Capacity Alert System Wiring Diagram
20030115
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