CRANE RELIABILITY Mechanical Faults CENF TARGET AREA - OVERHEAD CRANE Hoist (lifting movements)

CRANE RELIABILITY Mechanical Faults CENF TARGET AREA - OVERHEAD CRANE Hoist (lifting movements) Possible faults: 1.Fault of main motor: emergency motor (not used in normal conditions) is activated and the crane can continue lifting/lowering the load at ~ 1/10 of nominal speed; no intervention of personnel on the crane is required 2.Fault of one rope: the seconde rope can be designed to sustain alone the load (including dynamic effects) so that the crane can safely lay the load before personnel intervention 3.Fault of lifting gearbox: the fault is detected and the emergency brake avoids the drop of the load; personnel intervention to replace the damaged part is required

CRANE RELIABILITY Mechanical Faults CENF TARGET AREA - OVERHEAD CRANE Hoist (lifting movements) -Fault of lifting gearbox is very unlikely to happen: never happened in HE experience -A design which avoids the intervention of personnel when this type of fault happens is possible but the cost and the size of the crane significantly increases -Probability of gearbox fault can be further reduced through: 1.Oversizing: gearbox is designed as if it would be used in a heavy-duty crane (continuos use under impact loads) 2.Prescribing more frequent maintenance inspections

CRANE RELIABILITY Mechanical Faults CENF TARGET AREA - OVERHEAD CRANE Cross and Long travel (horizontal movements)

CRANE RELIABILITY Mechanical Faults CENF TARGET AREA - OVERHEAD CRANE Cross and Long travel (horizontal movements) -All the 4 wheels are motorized with self-braking motor+gearbox -In normal conditions only 2 motors are working; the other 2 motors are not used and their brakes are left open -Motors and brakes are independently controlled -In case of fault, the emergency motors are activated -No intervention of personnel is required

CRANE RELIABILITY Electrical Faults CENF TARGET AREA - OVERHEAD CRANE -Cubicles (both power and control) are located in a separate room outside the crane -Only junction boxes are left on the crane -In case of fault no intervention of personnel on the crane is required