Drives for Ramjet Technology Being Tested at Siemens

Issue 6 and Volume 106.

For the past several years, Ramgen Power Systems of Bellevue, Wash. has been developing a new power generation concept based on early jet engine technology – commonly referred to as ramjets. Developers say the Ramgen engine is expected to produce power at a cost competitive with electric grid prices.

Instead of generating thrust for missiles, the Ramgen engine converts thrust into rotary force for power generation. The application of ramjet technology leads to an engine that is simple and only has one major rotating component. Potential fuels for the engine are low-pressure, medium Btu waste gases from oil refineries, petrochemical and mining operations, or any other source that produces byproduct combustible gases with sufficient heat content.

The Ramgen engine requires a starter – something to drive it up to supersonic rim speeds. Siemens hopes to determine a suitable drive for the Ramgen engine upon commercial application and has been evaluating drive products from various vendors. The Ramgen engine uses a Siemens 6SE70 drive to initiate rotation of a starter motor that brings the engine up to speed for testing. During testing, test engineers use the drive to maintain precise control of the engine. The drive controls the starter motor, which in turn controls engine speed. Such fine speed control enables the current system configuration to test fuel injection, fuel mixing functions, and air film cooling techniques.

Illustration courtesy of Siemens.
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Ramgen test engineers believe that, compared to the other units, the 6SE70 is more precise, more powerful and performs better than the drive previously used.

While Ramgen Power Systems is small, its management sees a big future. Ramgen engines are being designed to work reliably for use in distributed generation applications. To fulfill worldwide potential for this technology, one or more strategic partners will most likely be involved in commercializing the Ramgen engine technology.