On Thursday 30 November 2017 23:32:48 Cecil Thomas wrote: > Gene, > I guess you could understand why all the talk about gearboxes and 2 > speeds and motors speeding in multiple K revs was confusing me a lot > when I thought you were talking about the Sheldon. > How close was my remembrance to about right? > > Cecil
Probably pretty close, except it won't get to 3 grand useing either motor, too much friction in the bronze bushing spindle bearings, yet they do not heat enough at the 1700+ it can reach even with e vfd. Besides, 1700 is a bit outrageous for a 6 or 8" chuck anyway, throwing lubricant 20 feet or more. 99% of this machines work will be done well below 1000 revs even in css mode. I did replace the upper cone pulleys shaft bronze sleeve bearings with the torrington needles the parts book says s/b in it, but in the process of removing that shaft, I found the real source of heat was not the bearings, but the twin grove pulley had been install wrong face to, and the shaft key was missing so the set screws were slipping and scoring the shaft. So I rebored the pulley on TLM and made a taperlock hub out of it since the slippage had scored that shaft pretty bad. Never did find the key so I had to find some of those, then gave up trying to put it back in w/o looseing the key, so the taperlock is doing all the drive now. The bore of the pulley was wobbled out at least twenty thou, so the taperlock actually makes it run truer than the key and setscrews would with that much wear. All that lowered the temps of the bearing yokes about 100F! I bought enough bearings to do the lower shaft too, but its never heated. This motor (I got 2 of them from an air compressor being replaced at the local horsepistol recycler for a $50 bill) has a 1" larger pulley, and a full 1" shaft, so I didn't try to bore the oem pulley out to fit this motor. So it runs a bit faster. Thats what the vfd is for. :) I have it scaled to a max of 180 hz, above that the phase slippage is obvious because the windings are down to less than an amp due to inductance, and I've limited the slow boost some, so I have an effective HZ range from around 8 HZ to a torque is already fading 120 Hz. And its not heating that much even at 8 Hz. I'd say that parts working well. > At 10:06 PM 11/30/2017, you wrote: > > > Are we talking about the same lathe? > > > > > > Cecil > > > >Actually, Cecil, no. All this is in re my G0704, which has also been > >cnc'd. 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
