Load Moment Indicators and Safety Devices 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 Load Moment Indicators and Safety Devices flashcards as text
When an LMI system displays a load percentage of 95%, what should the crane operator do?
Answer: Slow all crane movements and prepare to stop operations
At 95% of rated capacity, the operator should slow movements and exercise extreme caution because small changes in configuration can quickly push the load past the rated limit.
Which factor does an LMI system use along with load radius and boom angle to calculate rated capacity?
Answer: Boom length and configuration
Boom length and configuration (including jib attachments) are essential inputs that the LMI uses together with radius and angle to determine rated capacity from the load chart.
An anti-two-block (ATB) device activates and stops hoist-up movement. What should the operator do first?
Answer: Lower the load or extend the boom to create clearance
The correct response is to lower the load or adjust the boom configuration to re-establish clearance between the hook block and the boom tip sheaves.
Which of the following is NOT a standard input sensor for a crane LMI system?
Answer: Ambient air temperature sensor
Ambient air temperature is not a standard LMI input; standard sensors include boom angle, boom length, and load measurement via load cell or pressure transducers.
A rated capacity limiter (RCL) differs from a basic LMI primarily because it:
Answer: Automatically stops crane motion when rated capacity is reached
An RCL not only indicates load percentage but also automatically intervenes to stop crane motions that would exceed rated capacity, whereas a basic LMI only provides warning.
What condition can cause an LMI to display an artificially low load reading, creating a false sense of safety?
Answer: Dynamic loading from sudden starts or stops
Dynamic loading from abrupt crane movements creates transient forces not fully captured by the LMI's static sensors, potentially causing under-reading during the motion.
The NCCCO standard requires that LMI devices be calibrated:
Answer: In accordance with the manufacturer's recommendations and after major repairs
Calibration must follow the manufacturer's schedule and is also required after any major repair or component replacement that could affect sensor accuracy.