With a product that already provides an efficiency rating in the mid-90% range, Kato Engineering challenged itself to do even better. The result is a newly designed and patented generator concept called Laminar Cross Flow Technology. At 1.5 megawatts and above, We now offer generators that produce power at up to 98% efficiency, with 0.9PF load, based on IEC methods and calculations; the company said.
Recently introduced to the genset marketplace, Kato Engineering's Extreme High Efficiency line began as a concept proposed in 2007. A development team was assembled in early 2008, with prototype-to-concept validation later that year. Additional models were designed and tested from 2009 to 2011. Overall, it took four revisions of the original prototype to reach the 98% goal for the largest generators and a 1.5 to 2% gain compared to other Kato units in this size range
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A patent was granted for the new high-efficiency generators on July 19, 2011.
The new generator is available in 1 to 4 MW at speeds from (1500 -1800) rpm . Larger designs up to 15 MW and slower speed (750-1200) rpm ) units are also planned for future development.
The Extreme High Efficiency units have a similar footprint to existing Kato generators and are differentiated in outward appearance by the design of its cooling fans. Although designed for multi-genset, gaseous-engine, and micro-grid installations, the new generator could also be used in diesel engine emergency power applications.
Eight concept development team members between the Kato Engineering facility in Mankato, Minnesota, U.S.A., and the Leroy Somer facilities in Lexington, Tennessee, U.S.A., and Angouleme, France set out to reach the 98% goal with the first prototype, a 1600kW, 480V machine. The team used Flux2D and ANSYS E-Mag software, which proved to be beneficial tools for optimizing the magnetic design.
The engineers at Kato Engineering concentrated heavily on two parasitic loss areas - friction and windage. Traditional machines employ a cooling fan attached to the main shaft. This fan is always spinning and consuming horsepower. The designers came up with the radical idea of removing the shaft-mounted fan altogether and replacing it with a blower area that uses fractional horsepower electric fans when needed. This cut fan losses by half. The re-design fan is the most visible change to the new high-efficiency generator.
We attacked all areas of losses, not just the most common ones. Optimizing the generator's magnetic design included studying lamination, materials, configuration, winding design, and insulation for both rotor and stator. The other area closely examined was stray load losses. We re-designed the laminations, damper cage, all aspects of the magnetic circuit.
Friction and windage studies including employing a Computational Fluid Dynamics (CFD) program to design better airflow pathways through the generator in order to reduce dead zones that may trap air and improve laminar airflow. Considerations were also taken on the rotor to reduce or eliminate non-laminar flow. It would be comparable to a car being tested in a wind tunnel where the smooth air over the object is the laminar flow, while the turbulent area at the back of the car is the non-laminar flow. The rotor was also streamlined to remove any projections.
We optimized our magnetic design to reduce losses and optimized our air flow to reduce friction and windage losses.
Although the company has reached a milestone with this generator, Kato Engineering will keep pushing ahead to reach even greater efficiencies.