On Saturday 13 February 2021 18:35:40 John Dammeyer wrote: > > -----Original Message----- > > From: [email protected] > > > > On 2021-02-13 18:10, John Dammeyer wrote: > > > Friday night I put everything back onto the mill to make sure that > > > with all the cabinetry and wiring changes (including a new Knee > > > Motor) that I hadn't broken anything. > > > > > > Everything works as this video demonstrates. > > > https://youtu.be/I6lvnYhlez4 > > > > Nice demo, and impressive speeds. > > > > What is the max speed of the spindle? > > > > Marcus > > The 3 pulley combination with single phase motor was 2950 RPM and from > what I've read you don't really want to push the stock bearings past > that. > > The Bergerda 1.8kW Servo is 3000 RPM with two custom pulleys for 1:1. > I can also get about 1.5:1 with a slightly different pulley set to > increase torque at lower speeds if I need it. So far with what I've > done I've not seen major loading. I'm using PWM to a small far easy > 0V to 10V module which limits low speed to 100RPM and does go to 3000 > RPM. > > When I had the setup on the bench this week I ran a motor with > step/dir instead of PWM. Easy with MACH3 because you just change a > check box for PWM (1kHz) or STEP with appropriate tuning for max RPM. > At the moment impossible using the MESA 7i92H without running > different wires from the second parallel port. Or going through the > process of reprogramming the existing PWM pins to have a step/dir > module instead which I don't know how to do. Be nice if the FPGA > firmware had a few parameters that could be set from the HAL file to > select either PWM or Step/Dir. I'm using the stock MESA > 7i92_C11Gx2D.pin file. > The software pwmgen and the mesa pwmgen have both step/dir and individual dir steps in mode=2, where it pulses one wire or the other, this can drive a full bridge driver from the bob's 2 outputs.
What I don't know is if your bergera drives can handle that style of signal, My home made servo is using these mode 2 signals straight into a $6.40 BTS 7960 dual half bridge. Its rated for 27 volts, at up to 43 amps, develops absolutely no heat running a 24 volt 100 watt motor with a worm output, from a 400 watt, 24 volt psu, which is driveing the worm of a BS-1 at about 2 to 3 rpm at the chuck to an accuracy of about .0003 degrees. The ONLY failures I have had was when it was running wide open and I sent it a reverse, that will crowbar the 400 watt supply and shut it down for a couple minutes to cool, no smoke was let out and no kittens were killed. Cycle the power after the psu fan quits blowing hot air and its ready to do it again. > The technique for stepping under WIN-XP parallel port does create > considerable jitter and inaccuracies. I found when I set up to create > a step rate for 3000 RPM after 20 or so seconds the servo would fault > with a following error. The motor itself is limited to 3000 RPM so if > you exceed that step rate then eventually it can't keep up. > > Setting the step rate to give me 2980 RPM (as indicated on the > Bergerda LED display) no longer created the following error. I could > probably tweak it closer. I did not try moving the USB SmoothStepper > over from the CNC router to see if it was more stable. Don't care > really. I seem to boot into LinuxCNC more often then MACH3. > > Under LinuxCNC I expect with the MESA once I've assigned HAL Pins > configured to use one of the step/dir modules that the step rate for > 3000 RPM will be very precise. But even then I'm probably best to aim > for 2950 RPM. > > Oh and I think the other reason it wouldn't be a good idea to go above > manufacturers recommended 2950 RPM is that when I tighten the quill > clamp the bearing noise in the spindle changes. I don't know if > other mills do this but it's certainly not encouraging. > I have not noted such an effect on my ultra cheap GO704. I wouldn't be encouraged either. Stay well John 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
