Cavitation in a pump can commonly be caused by what issue?

Cavitation in a pump primarily occurs when there is a significant drop in pressure at the pump's inlet, which can cause the liquid to vaporize and form bubbles. These vapor bubbles can collapse violently, leading to damage and reduced efficiency of the pump. An air leak on the suction side of the pump introduces air into the system, which effectively lowers the pressure in the suction line. This drop in pressure can lead to conditions favorable for cavitation, as the fluid may reach vapor pressure, resulting in the formation of bubbles.

By causing a loss of prime or reducing the net positive suction head available to the pump, an air leak facilitates the conditions leading to cavitation more than other options provided. Understanding the relationship between pressure and the potential for cavitation is crucial in maintaining pump performance, as it demonstrates how ensuring a tight seal on the suction side can help prevent this damaging phenomenon.

In contrast, the other choices do not directly cause conditions conducive to cavitation. For instance, an increase in temperature typically increases vapor pressure, which would not induce cavitation in normal operational conditions. Similarly, overloading the impeller or providing excessive lubrication does not relate directly to the suction pressure issues that lead to cavitation.