High speed turboalternator for domestic combined heat and power unit

As part of an investigation into small scale gas turbine combined heat and power (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 32,000 rpm, 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.