On Saturday 20 August 2016 19:33:26 Gene Heskett wrote: > On Friday 19 August 2016 23:16:47 Gene Heskett wrote: > > Had to quit for much of the rest of the weekend, need some steel, and > TSC doesn't satisfy my hunger with their crappy hot roll. > > But I've a question, based on what I know about steppers. > > That 1600 oz/in I took off the mill that was falling over at 30 ipm > going up is being a puzzle. The 9x0 oz/in I put on in its place has > no problem with 90 ipm.
Thats a failure at 2.5 RPS, and the other motor is happy as a clam at 7.5 RPS. > > But I wanted to see what might be its limits just laying on the table, > with the same 60 volt psu, and the same DM860 driver. I hooked it all > up and drove it with my function generator. At 100 revs, it could run > the rotisary spinning this house. So I cranked up the kilohertz, > after setting the DM860 for its nameplate rated 3.5 amps. and a /16 > divisor. That label on the DM860 tries to fool you, its minimum > divisor is 2. > > It finally stalled at 150 kilohertz! [...] I went out to mount that new apron plate today, and found I needed one more cutput in the top edge, to allow the X screw shaft to pass thru it. So I measure its diameter, and carve a hole that fits it rather precisely, so precisely I had to revert to the time honored mill bastard an knock off 64 years worth of high spots & dings. That left a mess at the top as my tool is getting dull and it was cutting thru the edge of an old small threaded screw hole, so I went y=0x-radius, and plowed a straight line to the top of the plate. Went back y0xradius and plowed the other side so I can slip the plate into place from the bottom. Done, walk back over to the Sheldon to check fit, and found it had hidden teeth. You cannot see it, but from the X feed bearing to the left end of the saddle is 5", flip the tape measure to the other side and its 5.375". So I said screw it to myself, and made a 3/8" bigger cutout, moveing the 0,0 point 3/16" to the left. And I was doing so good at fixing it up with filler that a coat of paint will hide. To top that off, the v cutout for the cross slider overhang is just as far off center but it clears anyway. Sigh. Looks like rank beginner made it.. Oh, wait, I am one of those. Ordered a nema 34 right angle mount bracket tonight for this big ugly Z motor. It will sit where QCGB was but with things spaced so that the screw is as close to the bed and some higher, however far I can lift it to keep the swarf off it. The rack will be removed too, which will raise it another half inch or more. Since it won't have weight to lift, just inertia and friction, I'll be surprised if I can't get 200 ipm rapids. Friction is not that high, with the taper stuff uncoupled, I can push it full length of the bed with a 10 lb push once its moving. Thanks for reading. 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> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
