Drives Save Labor And Reduce Energy Costs

Variable frequency drives save labor and reduce energy costs while extending the lifespan of equipment for industrial applications. In the following ABB case study, a farm owner began looking tor alternatives to an old irrigation system, which worked by running the water pumps at constant speed, with control than being done by manual opening and closing of valves In the pipelines. The system still worked, but it was certainly not energy efficient. In addition, the need tor manual opening and closing of valves during startup combined with frequent power outages and voltage dips from the electrical utility, made the whole process vary labor-intensive. To start one of the six pumping stations could take one person up to an hour and with sometimes as many as three power outages a day, start ups became almost a full-time job.

The young owner of this farm was not previously a customer of ABB, but upon meeting with ABB energy efficiency engineers, he decided to test variable frequency drives (VFD) on the water pumps at one of Its six pumping stations. ABB recommended a VFD and working with a system integrator, assisted in the design, installation and commissioning of five variable frequency drives running irrigation pumps with 45 to 75 kW motors, and the sixth variable frequency drive used on the water transfer pump. The results were quite dramatic. With the new VFD installed, Riecor saw a significant drop in electric energy. Demand from the irrigation system went from 291 kW, 308 kVA down to only 175 kW, 186 k:VA. This amounted to 116 kW; an impressive 40 percent reduction in electric consumption for just one pumping station.

In financial terms, based on the local crop factor tor this region that Indicates the irrigation pumps would operate at 2,970 hours per year means an annual savings of $19,700 U.S.D. in electricity costs. The payback time amounted to a short 7 months. The farm quickly made a repeat order and has installed similar drives on a second pumping station

Major Benefits
In addition to the financial savings on the electricity bill, the farm also had further operational savings in both labor hours and troubleshooting the initial start up process. Operators now only need to flick a switch to start, and in the event of power interruptions the system would start back up automatically at pre-set times. The variable frequency drives give a long ramp-up time that allows for a very smooth pipe filling process, so the previous mechanical stresses on the pump couplings during start up were completely eliminated, together with fewer friction losses in the pipes. Additionally water hammering following switching off disappeared and fewer losses on the impeller were seen due to these extended ramp-up and ramp-down times.

The ABB Energy Efficiency engineers who worked most closely on the project, says that the Riecor Farming installation is a good example of how energy efficiency projects can also give additional benefits on the operational side.

Cost efficient retrofit

• 40 percent reduction in energy consumption gave rapid seven- month payback of investment
• Reduced labor costs, manpower needed for startup process is dramatically reduced
• Smoother operation and pipe filling, power drops handled easier, water hammer and system shocks eliminated

To learn more about applications where drives save labor and reduce energy costs, or for additional information about ABB Drives, visit the ABB Website. For ABB variable frequency drive repair or replacement, contact Precision Electric, Inc.