7.21.1 Normal Operation/Emergency Operation Change over Switch
The crane can be used when electrical power fails by means of the normal
operation/ emergency operation change over valve located on the main control lever
The valve is moved forwards to allow hydraulic pressure to bypass the safe load
control (SLC) valve, which has shut off the hydraulics to the crane, and permit the
crane to be operated.
CRUSH HAZARD. THE SAFE LOAD CONTROL (SLC) OVERLOAD PROTECTION SYSTEM
IS INOPERATIVE WHEN ELECTRICAL POWER HAS FAILED. GREAT CARE MUST BE
TAKEN TO ENSURE THAT LOADS DO NOT EXCEED THE RECOMMENDED SAFE BOOM
DISTANCES. SERIOUS INJURY CAN OCCUR TO PERSONNEL IF THIS INSTRUCTION IS
NOT COMPLIED WITH.
It is essential that the normal operation/emergency operation change over valve be
returned to the normal position as soon as electrical power is restored.
OPERATION CHANGE OVER VALVE
Figure 7.7 Location
of Normal Operation/Emergency Operation Change Over