High speed turboalternator for domestic combined heat and power unit

As part of an investigation into a small scale gas turbine CHP unit for the home, a high speed 1 kW permanent magnet cylindrical alternator has been constructed. For test purposes, the alternator was combined with the turbine and bearings from a commercial turbocharger to form a turboalternator capable of being driven by compressed air. A critical speed analysis of the arrangement was conducted and extensive tests were carried out at a speed of 32000 rev/min, at which point vibrations in the bearing housing became too large. At this speed the alternator was shown to produce its designed output. Machine power losses were estimated with a series of acceleration/deceleration tests