Counterweight and Ballast Configuration Flashcards
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Read the first 7 Counterweight and Ballast Configuration flashcards as text
What is the purpose of a 'superlift' or 'Mega Wing Lift' counterweight system used on very large crawler cranes?
Answer: It positions an auxiliary counterweight on an extended mast or ring to dramatically increase lift capacity
Superlift systems use an extended mast or large radius ring to position additional counterweight far behind the crane, maximizing the counterbalancing moment for ultra-heavy lifts.
When assembling counterweight slabs on a large crawler crane at a job site, who is ultimately responsible for verifying that the correct configuration has been installed?
Answer: The crane operator and the designated person directing assembly
Under ASME B30.5 and manufacturer requirements, the operator and the qualified/designated person overseeing assembly share responsibility for verifying the correct counterweight configuration before operations.
A hydraulic truck crane is configured with full counterweight for a heavy lift. Before traveling to the next pick point on a sloped road, what counterweight action may be required?
Answer: Remove some or all counterweight per the manufacturer's travel-with-load guidelines to prevent rear tipover on the grade
On a downhill grade with full counterweight and no load, the crane's rearward weight bias can cause backward tipover; manufacturers often specify reduced or removed counterweight for sloped travel.
What information must be confirmed on the counterweight identification plate or marking before accepting slabs from a rental yard for use on a specific crane?
Answer: The slab weight, part number, and compatibility with the specific crane model and serial number
Counterweight slabs must match the crane's specified part number and weight to ensure load chart validity; using incorrect slabs voids the manufacturer's ratings.
During a ring crane lift, the ballast ring rotates with the superstructure. What is a primary ground-bearing concern unique to ring cranes compared to conventional crawler cranes?
Answer: The rotating ballast ring applies concentrated moving loads around a large circumferential path that must be verified for ground bearing capacity
As the ballast ring rotates, it applies heavy moving loads around the entire ring circumference, requiring ground bearing capacity verification along the full ring path.
Which condition would require an operator to REDUCE counterweight from the maximum-rated amount despite having a heavy lift planned?
Answer: Working in a configuration where rear swing is restricted and backward tipover risk is elevated with max counterweight
When rear swing area is restricted and loads are light (or no load is lifted), maximum counterweight can create a backward tipover hazard greater than the lifting benefit.
A crane's load chart shows different capacities for 'with boom butt ballast' versus 'without boom butt ballast.' What does boom butt ballast primarily improve?
Answer: Front tipping stability at long radii and lower boom angles
Boom butt ballast, positioned near the boom foot, adds front-side tipping resistance and is most beneficial when working at long radii where forward tipping governs.