Tips to Tell if Your Mastra Pump is Running Inefficiently

Pump performance curves as part of the documentation provided by the pump manufacturers are based on actual tests. The curve shows how the pump should perform and serves as a valuable reference tool over the life of the pump. So an important question to ask is: “Is the pump delivering the flow and pressure that the performance curve says it should? And if it is not, the question becomes why not? ”

Let's create a scenario for the sake of discussion – our figurative pump performance curve says our 6SP30-12 Mastra pump is designed to lift 28 cubic meter per hour 100m to a tank. During operation, our pump only lifts 10 cubic meter per hour 100m to the tank. So the question is why is that ? Let check a few different things one by one below:

1. Has your EG motor been wired backwards? 

If the motor is improperly wired, then the motor can cause the pump shaft to rotate counter to the required direction. The pump will still pump fluid, but at a fraction of the flow and head indicated by the performance curve. So if your pump is not generating the correct rate of flow, please check that whether the shaft is rotating in the correct direction and swap the wires then test again. 

2. Have the bearings degraded or has the bearing lubricant become contaminated? 

For alternating current submersible motor will seek as much current as it needs to maintain its speed. However, if a shaft thrust or radial bearing is failing, it exerts a drag on the motor running; Industrial process pumps are often washed down; causing bearing lubricant to become contaminated eventually damaging the bearing. Once water gets into the bearing lubricant, bearings can degrade very quickly. Protecting bearings and monitoring moisture in the lubricant is critical to maintaining the reliability and the efficiency of the pump.

3. Are the impeller(s) and casing in adequate condition? 

Pump designers are very specific about the shape of the impeller and the casing, as these geometries play a vital role in the efficiency of the pump, affecting its ability to impart energy to the fluid. Erosion and corrosion can significantly change the shape of the impeller and/or the pump casing. Though pumps are designed with a corrosion allowance, damage beyond these limits can affect the hydraulic efficiency of the equipment. So if you would apply the pump in corrosive effluent, Mastra Team would recommend you to select that series: 4SP, 5SP, 6SP,8SP and 10 SP fully S.S.304 deep well pump, which is more corrosive resistant than POM engineering plastic impeller pump.

4. Have you selected the right pump for your specific application?

Oversizing submersible pumps is common. Specifying engineers choose pumps that generate more flow and head than the application requires.  They know over time the pumped fluid will wear the casing and the impeller.  The worn pump will eventually operate within an acceptable performance range.  The pump discharge will be throttled until the wear occurs, wasting valuable energy. 

5.Would a Variable Frequency Drive (VFD) help your pump operate more efficiently?

Many pump owner / operators are retrofitting their submersible motors with Variable Frequency Drives (VFD) to use only the energy needed to get the flow they need when they need it. So if lower flow is needed by the process, instead of throttling the discharge valve, the operator can change the motor speed by changing the current frequency, thereby using less energy.   We recommend identifying pumps in your operation which operate with partially closed discharge valves.  These may be candidates for VFDs, which would enable you to save energy.

Identifying inefficient pumps as part of an energy audit can be a great first step in reducing energy consumption and the cost of electricity. If you still have any problems, please feel free to contact our Mastra Team, we would more than pleasure to provide you professional service.