Counterweight and Ballast Configuration Flashcards
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Read the first 7 Counterweight and Ballast Configuration flashcards as text
When a crane manufacturer specifies a maximum counterweight for a given boom configuration, what is the primary consequence of exceeding that limit?
Answer: The rear stability limit may be exceeded, risking backward tipover
Excess counterweight shifts the tipping fulcrum rearward, potentially causing the crane to tip backward when working with light or no loads.
Which crane component directly connects the counterweight to the rotating superstructure and must be inspected for cracks before adding maximum counterweight?
Answer: The counterweight mounting brackets or tray
Counterweight mounting brackets or trays bear the full weight and dynamic loads of the counterweight and must be structurally sound.
A crawler crane's track gauge is widened before a heavy lift. How does this affect ballast requirements?
Answer: Widened tracks may allow reduced ballast by increasing the tipping-fulcrum width
A wider track gauge expands the crane's stability polygon, which can reduce the ballast needed to achieve the same rated capacity.
During a pick-and-carry operation with a hydraulic truck crane, counterweight configuration should be selected based on which primary document?
Answer: The manufacturer's load chart specific to pick-and-carry mode
Manufacturers publish separate or modified load charts for pick-and-carry operations that account for dynamic travel loads and may limit counterweight or boom configurations.
What does the term 'self-ballasted' mean when applied to certain crawler crane designs?
Answer: The carbody weight serves as the primary ballast without removable counterweight slabs
Self-ballasted designs incorporate the required ballast mass into the permanent carbody structure, eliminating separate removable slab counterweights.
A crane operator notices the counterweight is asymmetric — more slabs on the left side than the right. What is the safest immediate action?
Answer: Stop work and notify the crane supervisor to correct the configuration before any lift
Asymmetric counterweight creates unequal tipping margins in different swing directions, making the load chart unreliable; the configuration must be corrected before lifting.
On a lattice boom crawler crane, the manufacturer's rated capacity assumes a specific counterweight value. If a lighter counterweight is installed, what must the operator do?
Answer: Use a derating table or contact the manufacturer for a revised load chart
Using less counterweight than specified reduces rear stability and requires derating the crane's capacities per the manufacturer's guidance.