On Thursday, 24 March 2022 13:13:03 EDT John Figie wrote: > Now I am ready to figure out what to do for the spindle drive. > > The project is a 1972 Clausig NC lathe. The original paper tape fed > controls are long gone. I actually have the owners manual. The original > lathe had a 5 HP motor and a variable speed transmission similar to > bridgeport heads and many machines of that era. But that variable > speed drive is no longer with the lathe. The next owner fitted a large > PMDC motor to the machine - which I still have. IT is a beast of a > motor with tachometer feedback. The nameplate has a continuous stall > torque of 300 (in-lbs?), a peak amps rating of 320 amps, 4000 RPM and > 217 VDC. > https://drive.google.com/file/d/1O1217d-umZHpIvBtVZ4XCjMkOsplnwgu/view > ?usp=sharing Information in the manual indicates that original max > spindle speed was likely 2000 RPM. THe spindle is geared by a timing > belt that has a motor pulley of 30 and a spindle pulley of 47. The > next owner of the machine - who I purchased the lathe from removed the > DC motor and installed a 1750 RPM 5 HP 220V 3phase Baldor motor. The 5 > HP baldor is currently mounted on the machine. > https://drive.google.com/file/d/1aBlcbBWQ48A-brels9UIhQqBcvd0fiXx/view? > usp=sharing > > Now what to do about the drive for the spindle? > > 1) Keep the 5HP motor and use a VFD to run the motor faster to get my > 2000 spindle speed? 2000 * 47/30 = 3133 RPM. I don't have much > experience with induction motor drives. Is is feasible to run my motor > at nearly double it rated speed? Are these cheap single phase input > VFDs any good?
I'm using 2 of these but in the 1.5 horse sizing here, and they work extremely well when controlled totally by linuxcnc. For a 5hp, you'll need a 25 amp breaker in your service box. Thats a bit north of 10 gauge romex for a feed, so I'd use 8 gauge in conduit just to keep the inspectors happy. You might get by with a 20 amps and 10 gauge, but nuisance trips might be frequent, depending on how you have it tuned, and they don't come OOTB with anything like an optimum tune. They can be sped up for speed and direction changes by several orders of magnitude. My 1.5hp can reverse a 1hp, in first gear belt position, turning the 35lb spindle 100 rpms, in .25 of a turn. Thats somewhere between pretty fast, and damned fast. Belts slip if the pulleys are worn and bellyed out. Because the motors have inductance which limits the current at higher hz's, you'll find that 5hp is pretty well out of torque at 200 hz. You won't hurt the motor doing it unless its cooling fan is weak, it might explode. And if you limit the low speed boost to the motors FLA rating, you'll reduce the nuisance trips, and gain the ability to run it at 5hz for long enough to get the job done w/o burning your hand on the motor. A 4 pole motor, running at 400hz, will if it has enough torque, run at 12,000 rpms, about 2x faster than it can actually turn. 6 grand, aka 200 hz, s/b be considered the red line. > ebay link > <https://www.ebay.com/itm/224441224652?_trkparms=amclksrc%3DITM%26aid%3 > D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D237808%26meid%3Dff3ee > a0653834c509c5a592b1ba40972%26pid%3D101195%26rk%3D2%26rkt%3D12%26sd%3D1 > 83100064244%26itm%3D224441224652%26pmt%3D1%26noa%3D0%26pg%3D2047675%26a > lgv%3DSimplAMLv9PairwiseWebMskuAspectsV202110NoVariantSeed&_trksid=p204 > 7675.c101195.m1851&amdata=cksum%3A224441224652ff3eea0653834c509c5a592b1 > ba40972%7Cenc%3AAQAGAAACEOgL6rSsLbmX3BNmrTUtzjXFnK5T7FXeEWyt%252FMTCcEh > YXj1eFLAyDkUF3cgxnfgzv4cbJBL17cObzrqgUBjPnSWoDV9H%252F97l1QpjsMVxHCPzuc > B%252FPP6ChEn65wOcJuX02OVJD1Unud%252Bu2hc2MXKi6f0Et6zxgDKdbWzIhGOiBvW50 > 273%252FBxppgrKhznYp0UkdXIRUy29%252BbZHSIeWuW2%252Bt2I3J7EH0XSN759g%252 > FbRt%252FnkNo6gh5mrdMRTEfVmg8R7sG9BK7tqq2GvgeHESJB6MdVyo%252FXjdgKULT%2 > 52BhCCrID%252Bi1nAuMebMMPvcqjiP8ZBznpyFhQQ%252BdJIb%252BrSulGJT4Fr61R9f > urhXY91Rn0wjVaRYePwjkz42rvK7%252BZj4VzZ%252B84cXxI1MVp7yIZEMhDUePaBYQtu > uAzY6Bjkvrda%252B0Klnzv7EbxROkMBtZLkytuVi1DWS7UnVKZXmtrVRDPbuWkutRYsgVU > 86VoOBPZjxFxeiSeNbfqhmOkPUynaoRrBtiHtYcFDu4hXI5WOobACfyF%252F%252BJCOeg > nmLRb1MPehF0FD%252FyY8vGKJBvCk%252B2Vwxsm%252B6BG%252F8ac00UG1xRU6jJ2Kg > bGncP67f52W%252FpELM%252BjXwAK6reZZc0U087Yfiigoa3UdOvlftco2KjzVUY4gHq%2 > 52B7rmfkOb%252FKqoDC0QrFWEC4GBjd6YsOFO114iU%252BTV%252B9nIh0e9bfw%253D% > 253D%7Campid%3APL_CLK%7Cclp%3A2047675&epid=1772324768> > > More Pics > <https://drive.google.com/drive/folders/1U7o7AuiLQUyLCCwfV4zCoCtOD15Qpm > eE?usp=sharing> > > So far I have made my own torque mode DC drives for the x and z and > that seems to be working OK. I am using mesa 7i80 for I/O. Next I need > to start putting all the pieces together. > > The mechanics of the machine seem to be in excellent condition. > Probably because the machine has had little use even though it is old. > > John Figie > Take care John. > _______________________________________________ > 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, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
