Wire Rope Inspection and Replacement 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 Wire Rope Inspection and Replacement flashcards as text
What is the correct procedure for determining a wire rope's 'lay length' during inspection?
Answer: Measure the axial distance for one strand to make one complete helical revolution around the rope
One rope lay is the axial distance along the rope in which one strand completes a full 360-degree revolution around the rope core.
When replacing wire rope, what is the primary purpose of 'pre-forming' a new rope before installation?
Answer: To permanently shape each wire and strand into its helical position, reducing rotation tendency and improving fatigue life
Pre-forming shapes the wires and strands into their final helical positions during manufacture, reducing residual stress and the tendency to rotate or unlay under load.
According to OSHA 29 CFR 1926.1413, who is qualified to perform the monthly wire rope inspection on a crane?
Answer: A qualified person as defined by the standard
OSHA 1926.1413 requires that monthly wire rope inspections be performed by a qualified person who has specific training, knowledge, and experience in wire rope inspection.
What type of wire rope damage results from the rope repeatedly rubbing against a fixed object or the drum flange?
Answer: Abrasion causing flat spots and reduced wire diameter on the outer wires
Repeated contact with a hard surface causes abrasive wear, creating flat spots on the outer wire crowns and reducing cross-sectional area.
A wire rope shows 'fatigue fractures' with transverse breaks at the wire crowns. What operating condition most commonly causes this?
Answer: Repeated bending over sheaves or drums with inadequate D/d ratio
Fatigue fractures at wire crowns are caused by repeated cyclic bending stress from running over sheaves or drums, especially when the D/d ratio is too small.
When installing new wire rope on a crane drum, what is the correct method to avoid introducing a twist or kink?
Answer: Unreel the rope off a reel that rotates on a stand, or uncoil from a coil by rotating the coil on a mandrel
Rope must be paid off a rotating reel or rotating coil to prevent twisting; pulling rope off a stationary flat coil introduces one twist per loop.
What does the term 'wire rope efficiency' refer to when selecting a rope for a specific crane application?
Answer: The ratio of the rope's actual load capacity to its catalog breaking strength, considering efficiency losses from termination type and reeving
Wire rope efficiency accounts for strength reductions introduced by the termination method and multi-part reeving, yielding the actual usable load capacity.