NCCCO Tower Crane Operator Test 2

Question 1

What is the purpose of the slewing brake on a tower crane?

Accepted Answer

To stop the crane's rotation

Answer

The slewing brake is a vital control mechanism that allows the operator to stop and hold the crane's upper structure, including the jib and counterweights, in a desired rotational position. This prevents unintended movement and ensures precise load placement. It is specifically designed to control the horizontal rotation of the crane.

Question 2

What should be done if a tower crane begins to sway excessively during operation?

Accepted Answer

Reduce the load and stop work

Answer

Excessive swaying indicates a potential instability issue, which could be caused by factors like wind, an improperly rigged load, or an overloaded condition. Continuing to operate under such circumstances is extremely dangerous and risks a catastrophic failure. Reducing the load and stopping work immediately allows for assessment, identification of the cause, and corrective action.

Question 3

How should the hook block be positioned when preparing to lift a load with a tower crane?

Accepted Answer

Directly centered with the load

Answer

Positioning the hook block directly centered with the load ensures that the lifting force is applied vertically and evenly. This prevents the load from swinging unpredictably, minimizes side loading on the crane's components, and maintains the stability of both the load and the crane during the lift. Proper centering is crucial for a safe and controlled operation.

Question 4

When operating a tower crane near power lines, what safety precaution must be observed?

Accepted Answer

Maintain a safe distance

Answer

Operating any crane near power lines poses a severe electrocution risk if the crane or its load makes contact. Maintaining a safe minimum clearance distance, as specified by regulations (e.g., OSHA), is the most critical safety precaution. This prevents accidental contact and protects both the operator and ground personnel from electrical hazards.

Question 5

What is the primary function of the load moment indicator (LMI) on a tower crane?

Accepted Answer

To prevent overloading of the crane

Answer

The Load Moment Indicator (LMI) is a crucial safety system that continuously monitors the crane's load, radius, and boom angle to calculate the load moment. It provides real-time warnings to the operator if the crane approaches or exceeds its rated lifting capacity. Its primary role is to prevent dangerous overloading and potential tipping, ensuring the crane operates within its safe working limits.

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO Tower Crane Operator Test 2