On Saturday 12 November 2016 08:55:24 John Alexander Stewart wrote: > By the way - this is all good. I've dug out my ATS-667s from my > storage box, as this winter's project is to continue the long -dormant > CNC lathe conversion. > > VFD is done, now slowly working on the spindle sensors, so great > timing Gene! > I tried to use a 4 channel opto kit to drive mine, but the opto's were way too slow to deal with even a 10 kilohertz pwm, and they didn't go low enough at full song to get top speed out of the vfd. 3 volts drop when on.
So I drug out a mesa SpinX1 I bought years ago to use on TLM, then switched to one of Jon's pwm-servo drives which worked great there, so now the SpinX1 is running the vfd and doing a great job. Because the 3 phase motors I sourced from a recycle/junk yard are about 40 yo Centuries, and not vfd rated (but I got the pair of them for a $50 bill and replaced the noisy bearings in one of them) I've limited the vfd to 150 Hz max, which is 4500 revs, they run, with the cooling fan sounding like a siren there, and down to about 450 rpms. With a 4 speed belt drive down below I ought to be able to spin it at about any speed I need. And the SpinX1 gets rid of a few lines in your hal file because it translates the dir state into the individual forward and reverse command lines to vfd needs. And its translation of the pwm to an analog for the vfd 10 volt range speed in is quite linear. Peter once told me it was 1% or better. But at the higher speeds, I see a definite need to think about spindle gear lubricant in terms of hydrodynamic performance. When I first checked, the rear bearing was quite loose as someone had added some cereal box shims, which I took out, but put a 2 thou back in last night on each side as it was heating, and the 3/4 hp motor was tripping a 15 amp breaker trying to pull it in high gear, and the front was too loose to so I took out some there originally. But probing with an IR thermometer, it was still heating at the rear of the cap, so I put a 2 thou back in the front one designed and placed to lift the rear. And since Ed Nicely was kind enough to send me some shim stock, I think any paper shims will all be replaced with brass, shooting for about a thou of play, which will go away when its running if wet with oil. My original test was a 2 foot piece of pipe, chucked tightly and used as a lever with a dial on on end or the other of the spindle to give me an idea of how loose it might be. Shade tree engineering at its best! The rear was flopping around about 20 thou! Front was only a couple that I couldn't feel on the end of the pipe but could see on the dial. But removing it all made it so tight the motor couldn't move it, so its got to have enough clearance to move, and let the hydrodynamic effect of turning on the oil film tighten it up the last thou when its spinning. I wouldn't worry about journal scoring too much as long as its clean & well lubed since that damage usually mirrors itself on the shaft and cap and only counts if it has endplay. If it has endplay, take that up, then adjust the shimming to control the heat. There will be some because of the oil viscosity, so I'd not worry about the first 20F rise when its run in high gear for 10 minutes or so. More than that, add a .002" shim under the hottest end of whichever cap is heating. Lube science has come a long ways since these were built, and based on the results in my yard engines, starting easily in sub freezing weather etc, and the heating I have with the recommended 10W non-detergent, one of my next tests will be to switch to a modern synthetic in the 0w20 range for spindle bearing lube. I suspect the heating from the oil viscosity will nearly vanish. But the hydrodynamics should still work just like they do in your cars engine. > (slowly == work and life and family get in the way, but progress is > slow but sure on all my projects) There is that, but my "family" is long gone, leaving me with a missus slowly degenerating from COPD, down below 90 lbs now but she never was more than 125. Presently she is still pretty low maintenance, but I can see a higher maintenance future & barring another threat to me, I'll eventually be alone. But by then my back may have me incapacitated and unable to do this stuff at all. So I am trying to get the heavy duty work done while I can still walk. :( Take care 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
