🔍 Key Concepts

• Hydraulic gear pump inlet conditions (suction side vs. discharge side problems) • Effects of air entrainment, cavitation, and low NPSH (net positive suction head) on pump gears and housing • How reservoir pressure, breather condition, and oil temperature/viscosity affect flow into and out of the pump

💭 Think About

• Which choice would most directly affect the pump suction side and make it hard for oil to freely enter the pump, leading to collapse of vapor bubbles on the metal surfaces? • Compare how each option would affect pressure in the reservoir and flow in the return line. Which condition is most likely to create vacuum or starvation at the pump inlet? • Think about pitting damage: is it usually caused by high temperature and smooth flow, or by vapor bubbles forming and imploding on metal surfaces?

✅ Before You Answer

• Identify which option would reduce free breathing of the reservoir, changing pressure and affecting pump inlet conditions. • Decide which condition would most likely cause cavitation at the pump inlet (oil vaporizing and bubbles collapsing on gear teeth). • Check whether low operating oil temperature (and thus higher viscosity) alone is enough to explain rapid pitting in only two months, or if another factor is more directly linked.