> Toralf Lund wrote: > >>> But it IS driven by ultrasonic frequency AC. >>> >> My point is that an AC frequency can't be "ultrasonic" since electricity >> isn't sound. The vibration in a piezoelectric setup, on the other hand, >> in a way is. >> >> - Toralf >> >> > > Then there are no USM motors by your definition, which is incorrect btw. > Ultrasonic is jargon, referring to frequencies just above the hearing > range of humans. So an AC frequency above approximately 22KHz would be > Ultrasonic. No, I think you missed my point. Again, the "proper" USM motors are driven by elements that vibrate when applied to an electric field. This vibration is referred as ultrasonic, presumably because sound is also just vibration in a material, and in this case, the frequency of vibration is above the frequency of audible noise.
Running a traditional magnetic motor with a very high frequency voltage is not the same thing at all. > Note that driving a motor with AC current and a frequency > within the human hearing range will produce audible noise. So there is > good reason for this terminology. > > -Adam > > > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
