NCCCO Tower Crane Operator Test 1 — Questions and Answers

Question 1: What is the load hoisting sheaves minimum pitch diameter?

at least 16 times the diameter of the rope
at least 20 times the diameter of the rope
at least 18 times the diameter of the rope (Correct answer)
at least 15 times the diameter of the rope

Correct answer: at least 18 times the diameter of the rope

According to ASME B30.5 standards for mobile and locomotive cranes, the minimum pitch diameter for load hoisting sheaves must be at least 18 times the nominal diameter of the wire rope. This ratio is critical for minimizing fatigue and wear on the wire rope, extending its lifespan, and ensuring safe operation by preventing excessive bending stresses. Adhering to this standard helps maintain the rope's structural integrity.

Question 2: Boom length and angle can be utilized in a range diagram to ascertain

tilting axis
permitted load
ground force
load radius (Correct answer)

Correct answer: load radius

A range diagram, typically found in a crane's load chart, illustrates the crane's lifting capabilities at various boom lengths and angles. By locating the intersection of a specific boom length and boom angle on this diagram, an operator can directly ascertain the corresponding load radius. The load radius is the horizontal distance from the crane's center of rotation to the center of the load, which is crucial for determining the crane's capacity.

Question 3: How many line segments are needed to lift a 36,500 lb object? load if 9,000 pounds is the highest permitted line pull?

1926.14
3.5
5 (Correct answer)
45 ft.

Correct answer: 5

To determine the number of line segments needed, divide the total load by the maximum permitted line pull per segment. For a 36,500 lb object with a maximum line pull of 9,000 lbs, the calculation is 36,500 lbs / 9,000 lbs/line = 4.055 lines. Since you cannot use a fraction of a line, you must round up to the next whole number, requiring 5 line segments to safely lift the load without exceeding the maximum line pull.

Question 4: An auxiliary boom point sheave, sometimes known as a rooster sheave, is used primarily to:

Divide the hoist lines. (Correct answer)
Reduce the load's radius.
The front
Expand the boom's height.

Correct answer: Divide the hoist lines.

An auxiliary boom point sheave, often called a rooster sheave or whip line, is primarily used to provide an additional, independent hoist line. This allows for lighter, faster lifts without the need to re-reeve the main hoist line, or for handling two separate loads. It effectively 'divides' the hoisting capability, offering greater versatility and efficiency for specific lifting tasks.

Question 5: When the load moment indicator (LMI) on a crane malfunctions, what should an operator do?

Put an end to crane operations and notify the supervisor of the situation. (Correct answer)
Make the blast as brief as you can
At least as far back as the wall's subsurface depth
They depend on the crane's steadiness.

Correct answer: Put an end to crane operations and notify the supervisor of the situation.

The Load Moment Indicator (LMI) is a critical safety device that monitors the crane's load, radius, and boom angle to prevent overloading and tipping. If the LMI malfunctions, the crane's primary safety system is compromised, making continued operation extremely dangerous. OSHA and ASME standards mandate immediate cessation of operations and notification of a supervisor until the LMI is repaired and recalibrated.

Question 6: Before an operator exits the crane, he has to:

From the center of the boom tip sheave to the boom hinge pins
ANSI B30.5-3.1.2: Position all dogs or pawls inside the load when it is on the ground. (Correct answer)
Put an end to crane operations and notify the supervisor of the situation.
From the top of the reel to the top of the drum, the rope extends.

Correct answer: ANSI B30.5-3.1.2: Position all dogs or pawls inside the load when it is on the ground.

Before an operator exits the crane, especially if it's left unattended, all controls must be neutralized, the engine shut down, and parking brakes set. Engaging any locking mechanisms, such as 'dogs or pawls' for specific crane components or the hoist drum, is a crucial safety step to prevent unintended movement of the crane or its load. This ensures the crane is in a safe, secured state while unattended.

Question 7: When a crane's boom is lowered, what happens to the load's leverage?

increases the stability of the crane
It rises (Correct answer)
It remains unchanged.
It declines

Correct answer: It rises

When a crane's boom is lowered, the load moves horizontally further away from the crane's center of rotation, which increases the load radius. A greater load radius means the load exerts more leverage, or overturning moment, on the crane. This increased leverage reduces the crane's stability and overall lifting capacity, making the operation more critical as the boom angle decreases.

Question 8: When a crane operator gives two audible signals while operating the machine, what does it mean?

Never
He or she plans to proceed. (Correct answer)
He/she plans to provide support
From daily to monthly

Correct answer: He or she plans to proceed.

In standardized crane hand signals and audible signals, two short horn blasts typically indicate 'go' or 'proceed.' This signal is used by the operator to clearly communicate an intention to move or continue an operation. It's a universal signal designed to ensure all personnel on site understand the crane's immediate actions and maintain safety.

Question 9: What does the term "operating radius" mean?

at least 15 times the diameter of the rope
The separation between the load's center of gravity and the crane's center of rotation (Correct answer)
The load chart's specified capacity less the sum of the weights of the rigging and all attachments
at least 18 times the diameter of the rope

Correct answer: The separation between the load's center of gravity and the crane's center of rotation

The operating radius, also known as the load radius, is a fundamental measurement in crane operations. It is defined as the horizontal distance from the crane's center of rotation to the vertical line passing through the center of gravity of the load. This measurement is critical for determining the crane's lifting capacity from the load chart and ensuring stable operation.

Question 10: What minimal space between any portion of the crane or load and 850kV energized overhead power wires must be maintained, per OSHA 1926.1408?

25 ft.
30 ft.
45 ft. (Correct answer)
35 ft.

Correct answer: 45 ft.

OSHA 1926.1408 specifies strict minimum clearance distances that must be maintained between a crane or its load and energized overhead power lines. For power lines rated over 750 kV up to 850 kV, the required minimum clearance is 45 feet. This regulation is crucial for preventing electrocution and ensuring the safety of workers on construction sites.

Question 11: When the crane's boom length is in between the lengths indicated in the load chart, which capacity should you use?

At least as far back as the wall's subsurface depth
From the top of the reel to the top of the drum, the rope extends.
Depending on which next boom length is shorter or longer and has a lower capacity (Correct answer)
They depend on the crane's steadiness.

Correct answer: Depending on which next boom length is shorter or longer and has a lower capacity

When the crane's boom length falls between the lengths listed on the load chart, operators must always refer to the capacity for the next *longer* boom length shown on the chart. This is a critical safety practice because a longer boom length generally results in a lower lifting capacity at a given radius. By using the capacity for the next longer boom, the operator ensures they are working within the most conservative and safest limits, preventing potential overloading.

NCCCO Tower Crane Operator Test 1

What is the load hoisting sheaves minimum pitch diameter?