On Saturday 08 April 2017 23:57:30 Jon Elson wrote: > On 04/08/2017 07:09 PM, Gene Heskett wrote: > > On Saturday 08 April 2017 19:42:26 Jon Elson wrote: > >> On 04/08/2017 01:51 PM, Gene Heskett wrote: > >>> I need to go to tsc or somewhere, wallies maybe, and get > >>> me some of those 3 to 2 electrical adaptors as I just > >>> found my gigahertz sampler scopes 3rd wire ground pin is > >>> .2 ohms from a damned probe ground lead, so just hooking > >>> up a ground lead is making a ground loop. I may even just > >>> uncover the darned thing and see if I can find the jumper > >>> and cut it. What the hell were they thinking? > >> > >> The problem with that is they used to have line filters with > >> huge caps to line and neutral, and you'd get knocked on your > >> rear if you touched a scope with an isolated ground and > >> anything else. You could even get sparks off the ground clip. > >> Not sure your current scope has such a filter, but if so, > >> beware when using it isolated. > >> > >> Jon > > > > That consideration has indeed crossed my mind, Jon, so before I make > > it permanent, that will be checked. Those honking big line bypass > > caps have tossed me around a bit in the last 70 years. Not the most > > pleasant feeling... > > > > On the lcnc joint errors front, I unplugged the cat-6 and hdmi video > > to the monitor cables, pulled them out of the holes in the bottom of > > the box, and took them back to the pi from an overhead direction, > > putting 15" of air between the cables and the noise from the stepper > > drivers. It had, the last time I checked 15 minutes back, made 45 > > copies of lathe_pawn.ngc w/o a joint error. So I guess I go prowling > > about fleabay for a separate box to put whats now on the inside of > > the door in this too small a box. If I close the door, the whole > > maryann will be too close to the noisemakers. > > Yup, the noise produced by unfiltered stepper drives (or PWM > servo drives) is a major problem. > VFDs, too, of course. > > Jon > The vfd, since I put a Corcom 20 amp 3 phase brick wall between it and the cable to the motor, and a spinx1 to isolate the controls, hasn't been a major contributor to the noise. I thought maybe the filter would damage the vfd, but apparently its inductive enough to protect the vfd from its capacitors. vfd and motor power are now switched by the enable button by way of a 40 amp SSR on each side of the 254 volts.
Unortunately, most of whats available in boxes is too small, or too wwell ventilated to keep the swarf out. I need something about 14" long, 9 to 10 wide, and at least 3.5 deep internally. The only thing I could find over 2.5 deep, was also 15x17. And about $130. Nice, heavy alu construction, I could mount it on the outside face of this boxes door I think. I just can't convince myself to reach for the card. But if that what it takes... OTOH, knowing I could clear the top of an Automation Tech driver I bought to be able to put some speed into the x driver, I could swap out the 2m542 for it, and find a bigger toroid to power it up about 20 more volts, then that problem is solved. That m542 driver is running wide open driving that nema24 motor in parallel mode, and works well up to a bit over 40 ipm, but 41 vdc, just isn't enough. With the 60 volt switcher back in for a motor psu, and the ATech driver ought to get it up to 60+ ipm. OTOH, x speed on a lathe doesn't have to match z speed as the G0Z moves on the lathe are generally much longer than G0X retracts. In the end, I'll do what I have to. Spend the money... > ---------------------------------------------------------------------- >-------- 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 > [email protected] > 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
