Machinery and Magnetics > Ultra-High Speed Motors & Generators

SatCon has extensive experience in the development of high-speed motor and generator systems for a variety of applications.

High Speed Induction Machines

Figure 1: 45kW, 92 krpm, induction motor

Fig 1 shows a 45kW, 92 krpm, high-speed induction motor developed for the Army’s Combat Hybrid Power Systems (CHPS) program. This machine was for a direct drive generator off a diesel turbocharger for a military ground power application. The motor environment was 200°C with 50°C cooling air available to the rotor. A helical stator jacket provided liquid cooling to the stator. High temperature materials and analysis were required to meet the environmental conditions. A generator machine efficiency of 97% was demonstrated with the prototype. The controlled rectifier for this generator was developed to interface with a high voltage bus as part of a highly integrated electrical distribution system for the military vehicle.

Figure 2: Rotor Parts for 83.5kW, 100 krpm induction motor

Figure 2 shows the components for an 83.5kW, 100,000-rpm induction machine for an industrial air compressor. The rotor is integral to the two-stage centrifugal compressor shaft and is supported on air and magnetic bearings. We have developed similar integral starter generator (ISG) induction machines for gas turbine engine applications from 50,000 to 110,000 rpm.

Figure 3: 135 kVA 50,0000 rpm Air Cooled Induction Generator

Figure 3 shows an air cooled ISG for an aircraft APU developed for NASA. Table 1 shows generalized specifications for a high-speed induction machine of this type.

High Speed Permanent Magnet Machines

Fig 4 shows a 50,000-rpm permanent magnet motor developed with United Technologies Carrier under National Institute of Standards and Technology (NIST) funding for a Freon compressor for roof top air conditioners. Low rotor losses and a relatively large air gap helped boost system efficiency to demonstrate a significant energy savings for the system. During this project we also investigated various constructions for the high speed pm rotor including the two examples in Fig 5.

Figure 4: 20 kW 50,000 rpm Refrigerant Compressor

The first shows magnets contained in Inconel "cans" and the second shows them retained by a carbon fiber sleeve. The "can" approach provides good stability but requires more precision parts and expensive assembly operations. The composite sleeve is somewhat simpler giving lower production cost but has stability concerns in applications where the rotor may be exposed to high temperatures. An approach using metal retaining sleeves is currently under development.