On Monday 02 January 2017 00:56:48 Gregg Eshelman wrote: > What controller are you using? I need one able to handle a 110 volt > DC, 1.5HP treadmill motor. My 9x20 CNC conversion is on hold due to a > lack of motor controller.
The best controller you can put in there is a Pico Systems pwm-servo. Rated to 20 amps & 160 volts, its a full 4 quadrant controller, capable of reversing the 1 hp on my mill in 4 or 5 hundred milliseconds. Quicker yet if I'd let it as I have some hal logic to make it a little gentler. I am feeding it about 126 volts dc from a bank of toroids driving a 50 amp bridge and enough capacitance that I have to soft-start it else the turn on inrush will click a 25 amp breaker. > For running the saddle I picked up a ball > screw linear actuator exactly the right length. It's pitch is 16mm per > turn so I have a 2:1 reduction cogged belt. Full stepping on a 200 > step motor will get 0.04mm and half stepping will get 0.02mm > resolution on the saddle. That should be good enough for many things. > A 400 step motor would of course halve those. The 200 step Slo-Syn on > it is rated 5% accuracy so trying any finer stepping likely wouldn't > make the actual positioning any better. > > I used some corner brackets to mount the square body of the actuator > to the front of the lathe and made an aluminum plate that bolts to the > drive end of the actuator and the left end of the lathe bed to take > thrust loads. I am attempting to do this on the cheap. I picked up the > lathe for only $50, hardly any use on it. The linear actuator cost me > more than the lathe. IIRC I paid $50 for the treadmill just to get the > motor. Pieces of the motor mount and treadmill frame got cut and > welded to form an adjustable mount on the back of the lathe. The > original spindle pulley is turned down to press the treadmill's driven > pulley onto. I did have it running with one of those little $19 PWM > high voltage DC motor controllers from eBay. Problem was it couldn't > be run too fast without turning the fuse into a light bulb, or a > flashbulb. ;) > A familiar scene here in WV also. One of Jon Elson's PWM-SERVO amps, and a 100-130 volt dc supply will Just Do It(TM) The supply will need to be isolated so that the -common on the amp is at ground. You will probably find drive parts are fragile if you give that motor its head. And pin the flywheel to the motor shaft as strongly as you can since a violent reversal will unscrew the flywheel from the motor shaft. > I wanted to get a Denford Orac, until I saw a forum thread showing a > teardown and retrofit of one. All those are is an 8" swing Compact 8 > clone with the back 3rd of the cross slide cut off. I did use that as > inspiration for milling out the saddle to make room for a wee little > ball screw nut. I'm keeping the full length of the cross slide to make > it more useful, especially if I use gang tooling plates. > > > From: Cecil Thomas <wctho...@chartertn.net> > To: emc-users@lists.sourceforge.net > Sent: Sunday, January 1, 2017 9:39 PM > Subject: [Emc-users] Inverting the PWM signal to mesa 7i78 > > I am running a cnc'd jet 9x20 lathe with a treadmill motor and dc > motor controller with a 5k pot for speed control in manual. > > > ---------------------------------------------------------------------- >-------- 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
