On Tuesday 27 July 2021 08:16:40 andy pugh wrote: > On Tue, 27 Jul 2021 at 12:41, Gene Heskett <[email protected]> wrote: > > > The only way to make the spindle feel "stiff" in your test would > > > be to close the position loop with the encoder, but then how do > > > you drive it as a spindle with a speed command? > > > > With a honking big power supply, and a high resolution encoder. > > I have 2 machines with 1hp rated motors, both claiming to be 90 volt > > You seem to have misunderstood my point. > > Is your spindle stiff against "wiggling" when running at low speed > under no load? My guess would be that it is not. > > And I also doubt that you are running it in closed-loop position > control, as a spindle.
Please define the difference. At creep speeds it sure acts like its under position control. And yes, its just as stiff at 20 revs as it is at 2700. That power is available at any speed when the Pgain is 20 or more. The ridiculous encoder resolution sees to that. One of the smarter moves I ever made was moving the encoder to an shop made extension stud sticking out of the rear of the motor. Quantization noise is inaudible now. 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
