Linear Dynamometer With Variable Stroke and Frequency

An improved linear dynamometer has been developed for testing linear alternators that are to be used to convert mechanical power to electrical power in free-piston Stirlingcycle engines. Both the frequency and the length of the stroke of this dynamometer can be varied continuously, even during operation; consequently, the dynamometer can be used to fully map the capabilities of a linear alternator throughout its service envelope (its operational range as defined on a plot of limiting stroke length versus frequency) in a single test.