Sorry I didn't specify the voltage well. It's three phase 380 volts. The VFD is fed directly with the 380 volts and no neutral.
El sáb, 4 mar 2023 a las 20:19, Leonardo Marsaglia (<ldmarsag...@gmail.com>) escribió: > Hi Gene, hope your doing well! > > >> IMO and unless the armature of that motor is some sort of a ferrite >> compound, that temp s/n should not be a problem. Most motors can handle >> temps too hot to lay your hand on them unless they are on their way out >> in some sort of shorted windings failure mode. Most motor iron is grain >> oriented silicon steel since about the end of WW-II, and that is not one >> on its failure modes. >> > > Indeed, from my experience with normal induction motors the temperature > this spindle reached shouldn't be a problem. I didn't measure it with a > thermometer but I felt it was somewhere in the 65ºC range. But since this > is a high frequency spindle motor and materials are a little different I'm > a little bit lost here. > > > >> The reason I mention ferrites is because there are ferrites that have a >> "curie point" temp below 100C. But I've never heard of the ferrites >> being used in motor armatures, just high performance transformer cores. >> But that does bring up the possibility that the problem is actually the >> vfd since its switching transformer is a prime candidate to use such a >> ferrite compound. But that failure is in my experience, permanent >> because if it passes the curie temp while energized, there is no >> recovery short of returning the core to Arnold to run it thru their heat >> treatment again to re-establish its magnetic properties. >> > > Interesting, I didn't know they used materials with such a low curie > point. > > >> In both of those failures, encountered in H.P. brand power supplies at >> the tv station, it was as if the core was replaced by air, and it >> happened at such a low temp that the green paint on the core was not >> discolored. >> >> I'm just guessing about your setup, my only high rpm spindle is the 24k >> rev water cooled one I replaced with a better one on my 6040 mill, where >> the water tank is about 4 gallons and a 3 day job making a hard maple >> screw only gets the tank up to 36C in my air conditioned >> garage/workshop. Its insulated, 6" walls full of cocoon, and a foot of >> it on the ceiling, with a measly 5k btu window AC to cool the place. >> >> It sounds as if the motor is on its way out, but I'd not be totally >> surprised to find the vfd was somehow being a problem. Measuring the >> motor inductance, looking for not more than a 5% difference between the >> three coils would be my first step. Next would be suitable light bulbs >> on the vfd. I'd say look at its output with a scope, but that voltage >> will probably destroy the scopes usual 10x probes, and high voltage 100x >> probes are mail order far away. >> >> Whats your normal wall voltage? >> > > I have 380 volts but I didn't had the chance to measure it today. I'll do > it tomorrow. I wasn't worried about that because I assume the VFD would > trigger an alarm in case of a voltage drop or missing phase. In fact all > the servo motors are working ok. I just really hope this is a bearing > problem, although I will have to import them anyway. > > > > El sáb, 4 mar 2023 a las 17:12, gene heskett (<ghesk...@shentel.net>) > escribió: > >> On 3/4/23 13:53, Leonardo Marsaglia wrote: >> > 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. >> > >> >> IMO and unless the armature of that motor is some sort of a ferrite >> compound, that temp s/n should not be a problem. Most motors can handle >> temps too hot to lay your hand on them unless they are on their way out >> in some sort of shorted windings failure mode. Most motor iron is grain >> oriented silicon steel since about the end of WW-II, and that is not one >> on its failure modes. >> >> The reason I mention ferrites is because there are ferrites that have a >> "curie point" temp below 100C. But I've never heard of the ferrites >> being used in motor armatures, just high performance transformer cores. >> But that does bring up the possibility that the problem is actually the >> vfd since its switching transformer is a prime candidate to use such a >> ferrite compound. But that failure is in my experience, permanent >> because if it passes the curie temp while energized, there is no >> recovery short of returning the core to Arnold to run it thru their heat >> treatment again to re-establish its magnetic properties. >> >> In both of those failures, encountered in H.P. brand power supplies at >> the tv station, it was as if the core was replaced by air, and it >> happened at such a low temp that the green paint on the core was not >> discolored. >> >> I'm just guessing about your setup, my only high rpm spindle is the 24k >> rev water cooled one I replaced with a better one on my 6040 mill, where >> the water tank is about 4 gallons and a 3 day job making a hard maple >> screw only gets the tank up to 36C in my air conditioned >> garage/workshop. Its insulated, 6" walls full of cocoon, and a foot of >> it on the ceiling, with a measly 5k btu window AC to cool the place. >> >> It sounds as if the motor is on its way out, but I'd not be totally >> surprised to find the vfd was somehow being a problem. Measuring the >> motor inductance, looking for not more than a 5% difference between the >> three coils would be my first step. Next would be suitable light bulbs >> on the vfd. I'd say look at its output with a scope, but that voltage >> will probably destroy the scopes usual 10x probes, and high voltage 100x >> probes are mail order far away. >> >> Whats your normal wall voltage? >> >> >> > 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. >> > >> > 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
