18:2218:22, 24 May 2012diffhist−92
Variable-frequency drive
Changed to: '. . . and performance improvements due to the convergence of advancements in drives' semiconductor switching devices, drive topologies, simulation and control techniques, and control hardware and software.'
17:4617:46, 5 May 2012diffhist−9
Cycloconverter
Rewording to sentence starting with 'The input to output frequency ratio of a three-phase CCV must be less . . .'
17:4217:42, 5 May 2012diffhist0
Cycloconverter
Rewording to sentence starting with 'The input to output frequency ratio of a three-phase CCV must be less . . .'
18:2218:22, 24 May 2012diffhist−92
Variable-frequency drive
Changed to: '. . . and performance improvements due to the convergence of advancements in drives' semiconductor switching devices, drive topologies, simulation and control techniques, and control hardware and software.'
17:4617:46, 5 May 2012diffhist−9
Cycloconverter
Rewording to sentence starting with 'The input to output frequency ratio of a three-phase CCV must be less . . .'
17:4217:42, 5 May 2012diffhist0
Cycloconverter
Rewording to sentence starting with 'The input to output frequency ratio of a three-phase CCV must be less . . .'