On Thursday 09 July 2020 20:32:42 Gene Heskett wrote:
> > > Steppers aren't pwm driven, so ignore that. But a 48 volt supply > > > is pushing the ratings of a DM542 which is 50 volts max, and you > > > would be wise to adjust it a few volts lower. I have a pair of 7.5 > > > amp 48 volt supplies running my 11x56 Sheldon lathe, but they are > > > turned down to 42.5 volts, much safer, and it still marches at way > > > faster speeds than needed for a good cut. > > > > I can do that, I can put a voltage regulator between them. What do > > you mean by "safer" btw? I didn't see this during my previous reply. Don't do that, you'll find a teeny knob near the output strip that when adjusted, will set its output voltage. Don't assume that turning it CCW turns it down, so use a meter. Stepper drivers regulate the motors current by switching it on and off at ultrasonic speeds. The surplus current gets pushed back into the power supply and is used for makeup on the next cycle, so its got to pass current both ways in and out of the supply. This creates noise spikes that can easily overvoltage a 50 volt part, eventually blowing it, so always figure on about 5 volts less than the drivers voltage rating just so this microsecond spike won't eventually punch thru one of the outputs switching transistors. That will let out the smoke and break the mirror that makes all this stuff work. ;-) [...] > > One thing I might consider is belt drives, using very fine toothed > pulleys like a 3d printer uses, but since your motions are under 180 > degrees, I'd use smooth turned wheels, fastening the belt in slots in > the far side of a good sized wheel. Cheap, zero backlash, unlike an > expen$ive worm drive. Those belts are generally kevlar or dacron > backed, and zero stretch under long term tension. Buy them by the > foot. Use the money you save to buy your suds come your birthday. ;-) If this idea still moves it too coarsely, 3d print another 20/1 geardown to put between the motor and the big wheel. But because its slower sprocket will be turning several turns, it will need a continuous belt and real sprockets. Up to about 6" sprockets can be done on an Ender 3 printer. > > Ron > > > > >> thanks, > > >> > > >> > > >> Ron > > >> > > >> > > >> > > >> _______________________________________________ > > >> Emc-users mailing list > > >> Emc-users@lists.sourceforge.net > > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > Cheers, Gene Heskett > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > Cheers, Gene Heskett 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
