Well, I tested it for almost an hour with no load at 15000 RPM and the temperature settled at 55ºC in the bottom side where the bearings for the tool holder are, and almost 65º in the body part where the stator is. According to one of the Chinese suppliers of these spindles, 75ºC it's a pretty common working temperature. I'm still waiting for a detailed answer from the factory. This time, the VFD worked fine, no whining with no rotor spin. Now I need to cut some wood while monitoring the temperature during the process and hope the temperature doesn't go too high.
Anyway, I'm looking for new VFD drives just in case. From what I can tell the problem could be the VFD as Gene and Jon pointed out. I'll let you know how it goes when cutting wood again. Thanks to all for your help! :) El dom, 5 mar 2023 a las 18:11, gene heskett (<ghesk...@shentel.net>) escribió: > On 3/5/23 12:59, Leonardo Marsaglia wrote: > > By the way, one subtle thing I noticed too that leads me to the bearings > as > > a problem. > > > > Normally when the spindle is off and the dust removal vacuum system is > > working, the spindle tends to spin by itself because of the vacuum action > > on the impeller I installed. This almost never happened yesterday. So, to > > sum up: I was able to free turn the spindle by hand at all times, but the > > vacuum was not always able to make it spin the impeller and if it did it > > wasn't nearly as fast as days before. This is what makes me suspect about > > the bearings. Also, almost all the problems I experienced yesterday were > > with cutting forces involved, never with the spindle turning free. Could > it > > be that the extra heat and torque that's building up because of a damaged > > bearing is what's making the VFD triggering for overcurrent? > > > > What puzzles me still is when the spindle was too hot and with no load > the > > VFD only whined and couldn't make the spindle turn. This, as Jon pointed > > out, recovered on its own a few minutes later. > > > > I'll be there doing some tests in a few hours so I'll let you know if I > can > > note anything new. > > > > Again a lot of thanks to you guys for being so kind and helpful! :) > > > > El sáb, 4 mar 2023 a las 15:51, Leonardo Marsaglia (< > ldmarsag...@gmail.com>) > > escribió: > > > >> Hi guys. > >> > >> Sorry for the OT but I'm having a strange behavior with my spindle and > I'm > >> a little worried. > >> > >> The problem I had today for the first time is the spindle was getting > >> really hot and started to slip (you could hear the frequency from the > >> inverter was on spot but the rotor sometimes wasn't even turning).After > a > >> few seconds of slipping the VFD triggered the over current alarm and the > >> spindle was stopped. Once the the spindle cooled down it worked > perfectly. > >> This never happened before but also I must clarify that today the > ambient > >> temperature reached 40⁰C and I'm sure that under that roof where the > router > >> is placed there were 45⁰C so I suspect this has something to do with the > >> problem. > >> > >> The spindle is rated 11kw of max power output and is air cooled. It has > a > >> built in fan motor so it doesn't rely on spindle speed for cooling. It > >> always gets warm (there are several labels on the spindle’s body for > >> caution because of the heat) but nothing like today. > >> > >> Could this be normal because of the extremely hot days I'm having here? > >> Should I think about changing bearings or even rewind the motor? I've > only > >> had the over current alarms when the spindle was too hot. > >> > >> I will be really thankful if you can share your thoughts about this. > > I think I'd want to look at the solder joints on the big capacitors in > the vfd, keeping in mind that they can hold quite a charge for quite a > while when turned off, and that is definitely a lethal voltage. When I > said look, I'm looking with an old camera lens for a magnifying glass, > checking for hairline cracks in the solder, particularly at the edge of > the solder puddle where the copper foil begins, that is a favorite place > for some seemingly crazy thermal effects. And you can't just scrape it > down to clean copper & bridge it with solder, you must bridge the crack > with a piece of suitable gauge copper wire when patching such. And for > future crack development protection, a 2% silver bearing solder is much > stronger than the usual eutectic mix. > > Same inspection comments apply to the semi's soldered joints, heat sinks > can exert joint breaking forces as they heat. I have a couple of old > 16mm projector lenses that get me up close and personal views. An rch > looks like a saw log to them. > >> > >> Thanks for your help as always! > >> > >> Leonardo. > >> > > > > _______________________________________________ > > 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 > Genes Web page <http://geneslinuxbox.net:6309/> > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
