If a centrifugal cargo pump loses suction, what could be a potential cause?

The potential cause of a centrifugal cargo pump losing suction can indeed be attributed to incomplete priming. Inadequate priming means that there isn’t enough liquid in the pump casing or suction line to maintain proper hydraulic conditions. For a centrifugal pump to operate effectively, it must be filled with liquid to create the necessary pressure differential for suction. When priming is incomplete, air may be trapped inside the pump, preventing it from achieving the required suction to draw in the liquid cargo.

In contrast, while running the pump backwards or having a discharge head that is too high can affect pump performance, they do not directly cause a loss of suction due to the interplay of pressure and liquid volume in the pump system in the same way that incomplete priming does. These factors might cause operational issues, but they aren't the primary reasons for losing suction seen specifically with centrifugal pumps. The issue of losing suction is fundamentally tied to the ability of the pump to maintain a consistent liquid flow, heavily influenced by the state of priming.