CRANE RELIABILITY Mechanical Faults Hoist lifting movements CENF

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

CRANE RELIABILITY Mechanical Faults 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 CENF TARGET AREA - OVERHEAD CRANE

CRANE RELIABILITY Mechanical Faults 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 CENF TARGET AREA - OVERHEAD CRANE

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

CRANE RELIABILITY Mechanical Faults 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 CENF TARGET AREA - OVERHEAD CRANE

CRANE RELIABILITY Electrical Faults - 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 CENF TARGET AREA - OVERHEAD CRANE