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Noise is a critical acoustics parameter in engine based designs. Low speed operation gives a noise advantage; however, vibration is significant at low speeds. A practical Active Torque Cancellation (ATC) scheme is shown to reduce transmitted vibration by an order of magnitude at targeted frequencies. By focusing on critical roll torque components only, over-sizing of machine and power electronics components is avoided. Detailed design approach and experimental results are presented for a practical implementation.

Emerging fuel cell and micrnturhine technologies will complement more traditional gas and diesel engine generator sets io telecommunication applications. To understand how the relative merits of these new technologies will compete in future applications, it is necesary to also know how more traditional genset technology is evolving. Cummins Power Generation is currently developing advanced fuel ceU systems and advanced gaseous fuel reciprocating engines under DOE contracts. as well as launching commercial microturbine generating equipment. This paper compares quantified attributes of these evolving power systems against current generator sets io the next five-year time frame and also against the specific needs of a spectrum of telecommunication power requimments in the 5 kW to 1 MW sue range. Telecommunications ApplicationsTelecommunication electric power installations have traditionally been solely used for emergency standby power, however it expected that future installations will increasingly be used to operate for longer periods as a way to reduce overall Facility operating costs and provide higher system availability. These applications will increase as technical improvements in generating equipment are made and as favorable regulatory policies are enacted. Interruptible, peaking, and distributed generations are applications that can drive different equipment requirements. The cost of ownership will drive the economic incentive for these installations and increasingly stringent federal and regional emissions regulations must be met to obtain site permits. The relative importance of power system attributes as a function of operating hours is presented in Figure 1. MahetOperation Lan, Low IOW Low Segment H w r j p e r InitialFuel Maint. Emission L L L Standby <2W Peaking 1wO2wO Disuibuled 9 0 M ) M Generation Imcmame: Hoh. Medim. Low Figure 1. System Attributes vs. Market SegmentBy definition, standby gensets operate for the duration of a power outage and their merits are judged by reliability, low cost and ability to meet operating permitting requirements. Since they typically operate less than 200 hours per year, the cost of fuel, maintenance per operating hour, and the level of specific exhaust emissions are of secondary importance. As the operating hours of gensets are increased for economic benefit, the costs for fuel and maintenance become increasingly important, and the hurdle to meet emissions requirements becomes higher. Equipment CastsThe cost of emerging microturbine and fuel cell fuel technologies are significantly higher than For reciprocating engines due to the combination of the complexity of their mechanical systems, auxiliary equipment, output power conditioning electronics, and the relatively low production volume of key components. Figure 2. Contains the cost of generating equipment vs. their output for fuel cells, microturbines, and reciprocating engines over a five-year time Frame. During this period it is expected that microturbines will be more expensive than reciprocating engine gensets...