Complex sentence: In this context alternating current does not imply but does include a sinusoidal waveform, with minimal restriction on waveform; it must be periodic, and its frequency will determine motor rpm, and the waveform does effect the motors efficiency at transforming electrical to mechanical energy.
Split into simpler sentences: In this context alternating current does not imply but does include a sinusoidal waveform, with minimal restriction on waveform, it must be periodic, and its frequency will determine motor rpm. However, the waveform does effect the motors efficiency at transforming electrical to mechanical energy.