NEIEP Mechanics Practice Exam

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Prepare for the NEIEP Mechanics Exam with multiple choice questions, hints, and detailed explanations. Ace your test and advance your career!

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What occurs when a pump draws air instead of oil?

Flooding
Cavitation
Overheating
Contamination

The correct answer is: Cavitation

When a pump draws air instead of oil, this leads to a phenomenon known as cavitation. Cavitation occurs when the pressure in the pump drops below the vapor pressure of the liquid, causing the liquid to vaporize and form bubbles. These bubbles can collapse violently as they move into areas of higher pressure within the pump, leading to shock waves that can damage the internal surfaces of the pump and reduce its efficiency. In more detail, this situation typically arises when the pump is not adequately primed or when there are issues with the suction side of the system, such as leaks or a blockage that prevents the proper flow of oil. This results in the pump being unable to maintain the necessary vacuum to draw the oil effectively, at which point air is ingested instead. The consequences include not just potential damage to the pump components over time, but also a significant drop in performance and efficiency.