Mechanical Systems & Maintenance Practices Flashcards
7 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 7 Mechanical Systems & Maintenance Practices flashcards as text
What condition in a hydraulic system is indicated by a whining or cavitation noise from the pump, especially at startup?
Answer: Fluid starvation or aeration at the pump inlet
Cavitation noise at the pump occurs when the inlet is starved of fluid or air enters the suction line, causing vapor bubbles to collapse inside the pump.
During a pre-shift inspection, an operator notices the crane's boom hoist pawl (ratchet) is worn and not engaging properly. What action is required?
Answer: Remove the crane from service immediately until repaired
A boom hoist pawl that fails to properly engage is a critical safety device defect that requires immediate removal from service until the component is repaired.
What does a high differential reading between incoming and outgoing hydraulic filter pressure gauges indicate?
Answer: A clogged or loaded hydraulic filter
A high differential pressure across the filter indicates the filter element is loaded with contaminants and requires replacement before bypassing occurs.
Which type of crane structural inspection involves checking for cracks, deformations, and corrosion on the boom chord members and lacings?
Answer: Periodic inspection
Periodic inspections, typically performed by a qualified person at intervals specified by the manufacturer, include detailed structural examination of boom chord members and lacings.
A crane's counterweight becomes partially detached during operations. What is the immediate required action?
Answer: Stop all operations, lower the load if safe, and secure the crane
A detached counterweight is an immediate structural hazard; all operations must stop, the load lowered if safely possible, and the crane secured.
What is the function of the crane's swing lock or travel lock when the crane is being transported or when not in use?
Answer: Prevents uncontrolled rotation of the upperworks
The swing lock secures the upperworks against uncontrolled rotation during transport or when the crane is parked, preventing hazardous unexpected movement.
When replacing wire rope on a hoist drum, what is the minimum number of wraps that must remain on the drum when the hook is at its lowest working position?
Answer: 2 wraps
At least two wraps of wire rope must remain on the drum at all times to ensure the rope's anchor attachment point does not bear the load.