Mechanical Systems & Maintenance Practices Flashcards
6 cards from real NCCCO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Mechanical Systems & Maintenance Practices flashcards as text
What is a Load Moment Indicator (LMI) and what does it do?
Answer: An electronic system that monitors the crane's load, radius, and boom angle, warning when approaching capacity
The LMI continuously calculates the load moment (load weight × radius) and compares it to the crane's rated capacity. It provides visual and audible warnings as the crane approaches its limits.
What is the minimum number of wraps of wire rope that must remain on the hoist drum?
Answer: At least 2 full wraps at all times
A minimum of 2 complete wraps must remain on the drum at all times. This ensures the rope's termination point isn't the only thing preventing the load from falling.
What maintenance should be performed on outrigger pads?
Answer: Inspect for cracks, deformation, rot (wood), and adequate sizing for ground conditions
Outrigger pads must be inspected for structural integrity. Wood pads can rot or split, steel pads can crack, and all pads must be sized appropriately for the ground bearing capacity.
Why is it important to track the operating hours of a crane?
Answer: Operating hours determine when scheduled maintenance, inspections, and component replacements are due
Operating hours trigger maintenance intervals for critical components: engine oil changes, hydraulic filter replacements, wire rope inspections, and major component overhauls.
What is the purpose of the crane's anti-two-block device?
Answer: To automatically stop the hoist when the hook block approaches the boom tip, preventing wire rope failure
The anti-two-block device detects when the hook block is about to contact the boom tip sheaves and automatically stops the hoist to prevent two-blocking, which can break the wire rope.
What type of lubrication does wire rope require?
Answer: Regular application of wire rope lubricant to reduce internal friction, prevent corrosion, and extend rope life
Wire rope needs regular lubrication that penetrates to the core to reduce internal strand friction, prevent corrosion, and displace moisture. Proper lubrication can significantly extend rope service life.