On Saturday 19 May 2018 21:39:58 Jon Elson wrote: > On 05/19/2018 07:27 PM, Gene Heskett wrote: > > On Saturday 19 May 2018 14:47:46 Chris Albertson wrote: > > > > So its turning 3 whole revolutions per servo-thread. > > Assuming 1000 servo thread executions/second, that is 3000 > RPS or 180,000 RPM. > Did you forget to divide by 60? > Yup, common occurrence in my ancient wet ram. That means the maximum edge count per second is only 704750, which is still darn fast.
> (We have some stuff at work that actually runs at 5000 RPS, > but that is machinable ceramic running on air bearings, and > weighs barely a gram.) > Air bearings I am familiar with, the headwheels of the now ancient 2" quadruplex broadcast vtr spun on air bearings at 14,400 revs. Carried a magnetic head every 90 degrees on its rim. About 1.75" of a 2" wide tape was formed into a cylinder by a vacuum shoe as it was pulled past the spinning head, the wheel motor was also there, with a 2 phase servo amp driving it. Servo's kept growing power until the last iteration of such a machine could start from a dead wheel, and be making video in 400 milliseconds. This was the last though, circa 1975 or so. I think the surge power of the servo's was around 10 kw for that .4 seconds. But the armature of the motor, and the head wheel might have weighed 2 oz's. Once at speed, it might have used 2 watts a phase. An amazing machine in its day, over 40 years ago. > Jon > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
