Leonardo, are you sure about those Hz vs. RPM numbers? AFAIK all high speed spindles are 2-pole motors (correct me if I am wrong on this), then you should have 200 Hz for 200 RPS = 12000 RPM and 400 Hz for 400 RPS = 24000 RPM
Viesturs pirmd., 2023. g. 13. marts, plkst. 18:55 — lietotājs Leonardo Marsaglia (<ldmarsag...@gmail.com>) rakstīja: > > By the way, the nominal frequency is 400 hz at 12000 rpm. Nominal voltage > is 380 volts but that varies of course when the VFD is working. Max > frequency is 800 hz at 24000 rpm but I never came close to that. > > El lun, 13 mar 2023 a las 13:50, Leonardo Marsaglia (<ldmarsag...@gmail.com>) > escribió: > > > Hi Todd, and thanks for the response! > > > > Well the manufacturer only gave nominal and max speed for the spindle and > > a couple of graphics to see the u.f. and p.f. curves to have some guidance. > > I'm always using the spindle at 15000 rpm so I think that's ok. Also I've > > been using it like this for more than 6 months with no troubles and it was > > working almost 10 hours straight each day. > > > > The spindle sounds right when at high speed and with no cutting forces > > involved, I can't feel any difference from the first time I tested it. Also > > by hand it feels the same as always but that could be my perception off > > course. > > > > Anyway, last Saturday we tested it again. First 25 minutes of warming up > > without cutting. The temperature settled at 55°C at the body of the > > spindle. Then we cut a board for about 40 minutes. We monitored the spindle > > temperature at the bearings and stator and never exceeded the 65°C at the > > stator / 57°C at the bearings. VFD current, voltage and internal > > temperature were ok (no more than 43°C when working at full load on the > > VFD). Then we started to cut another board and that's when the VFD started > > giving problems. At the moment we tried to accelerate the spindle to 15000 > > rpm (I'm using a 10 seconds ramp approximately to reach 15000 rpm) the > > overcurrent alarm started . There was no way of making it to work. It looks > > to me that the VFD could be the problem because everything else was ok. > > > > Today I'm going to test it again before taking it apart, and then I'll > > open it and check the capacitors and all the joints to see if I see an > > evident problem there. But I'm almost 100% sure the problem is in the VFD. > > > > > > > > El lun, 13 mar 2023 a las 13:19, Todd Zuercher (<to...@pgrahamdunn.com>) > > escribió: > > > >> The wrong VFD settings can cause an overheat due to overcurrent. Were > >> you running the spindle at lower RPMs? Router spindles generally don't > >> like running at speeds less than 6000rpm, especially if the VFD settings > >> aren’t right. The VFD needs to be set so that it reduces the voltage > >> applied with reduced frequency. If this volt/hz reduction curve isn't > >> right, either you can over current and overheat the motor at lower speeds, > >> or if set too low you lose what little torque the spindle has. To know > >> what these settings need to be set to you need to know the motor's rated > >> speed and voltage at those speeds and current ratings. If the spindle > >> manufacturer didn't supply a midrange voltage setting, you may need to find > >> that setting experimentally. > >> > >> That said, high speed spindle bearings can be failing and the spindle > >> still spin mostly freely by hand, but the spindle will be loud at speed due > >> to vibration and will overheat if run for extended periods of time at > >> speed. A high speed spindle should be very quiet at speed (not sound like > >> a conventional router motor.) Check for any slightest notchy-ness, when > >> turning the spindle by hand. It is often more cost-effective to have a > >> loud spindle rebuilt before it totally fails, than to run it till it won’t > >> run anymore and then try to rebuilt it or have to replace it because damage > >> to the spindle is too severe. > >> > >> What are your spindle motor’s rated speed, voltage and current? What do > >> you have the VFD set up for minimum, maximum, base and mid-range voltages, > >> and frequencies? Yes, those are 8 separate settings that most VFDs need to > >> have configured to run a high speed spindle correctly. Unfortunately many > >> times the spindle manufacture will only provide you with the spindle’s > >> rated frequency and voltage (use this for the “Base” frequency and voltage > >> in the VFD) and the maximum frequency and maybe voltage. If you are lucky > >> and the spindle manufacture provided you with some numbers to use for the > >> mid-range settings if so, use them. They may not be called that, it might > >> just look like a low or minimum speed setting with a reduced voltage (might > >> be 5-7k rpm). If you don’t have a recommendation from the spindle > >> manufacture, experiment with different mid-range voltage settings to find > >> one that keeps the VFD’s current output safely below the spindles rated > >> continuous current. > >> > >> For example I was just working at replacing a VFD for an HSD spindle that > >> had recommendations for 7k rpm @ 220v for the mid-range, but I also had to > >> set the minimum frequency and voltage to 0.5Hz and 1.0v, to prevent the > >> motor from occasionally stalling on acceleration when starting from > >> stopped. When those settings were incorrect the drive would overcurrent > >> and shut down. When they were close but not quite right the drive would > >> run at high current and not always accelerate correctly (stalling). With > >> them correct the drive accelerates the spindle quickly and only shows peak > >> currents of about 15amps while doing it. > >> > >> PS I meant to send this last week, but forgot to click send, so it sat on > >> my work computer till this morning. > >> > >> Todd Zuercher > >> P. Graham Dunn Inc. > >> 630 Henry Street > >> Dalton, Ohio 44618 > >> Phone: (330)828-2105ext. 2031 > >> > >> -----Original Message----- > >> From: Leonardo Marsaglia <ldmarsag...@gmail.com> > >> Sent: Wednesday, March 08, 2023 9:20 AM > >> To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> > >> Subject: Re: [Emc-users] OT: Air cooled router spindle problem > >> > >> [EXTERNAL EMAIL] Be sure links are safe. > >> > >> In fact, the day the rotor slipped, when the spindle cooled down a bit, > >> it started to work ok until I had the problem again. What I'm mostly > >> worried about is, if this was caused due to an overheat, why did that > >> overheat occur in the first place? > >> > >> El mié, 8 mar 2023 a las 11:17, Leonardo Marsaglia (< > >> ldmarsag...@gmail.com>) > >> escribió: > >> > >> > Most high speed spindles (such as router spindles) are rather > >> > particular > >> >> about how the VFD is configured because of their low inductance. > >> >> What are your settings for base frequency and voltage? You may need > >> >> to adjust the settings for midrange frequency and voltage. What > >> >> these settings will do is adjust the volts/hertz curve to help keep > >> >> the motor from overcurrent when running at lower RPMs, and help > >> >> prevent stalls/excessive slippage on acceleration. These settings > >> >> usually need to be significantly different from most VFD's default > >> >> setting (which are usually configured for a 60hz > >> >> motor.) > >> > > >> > > >> > Hi Todd, > >> > > >> > I'll take a look and attach my settings as soon as possible for you to > >> > see. But this setup was working well until the extreme heat days > >> started. > >> > > >> > Could it be that the ambient temperature (40ºC or more) could have > >> > made the rotor slip effect worse? Maybe I was on the limit before and > >> > the extreme heat conditions triggered the effect? > >> > > >> > Thank you! > >> > > >> > El mié, 8 mar 2023 a las 10:57, Todd Zuercher > >> > (<to...@pgrahamdunn.com>) > >> > escribió: > >> > > >> >> Most high speed spindles (such as router spindles) are rather > >> >> particular about how the VFD is configured because of their low > >> >> inductance. What are your settings for base frequency and voltage? > >> >> You may need to adjust the settings for midrange frequency and > >> >> voltage. What these settings will do is adjust the volts/hertz curve > >> >> to help keep the motor from overcurrent when running at lower RPMs, > >> >> and help prevent stalls/excessive slippage on acceleration. These > >> >> settings usually need to be significantly different from most VFD's > >> >> default setting (which are usually configured for a 60hz > >> >> motor.) > >> >> > >> >> Todd Zuercher > >> >> P. Graham Dunn Inc. > >> >> 630 Henry Street > >> >> Dalton, Ohio 44618 > >> >> Phone: (330)828-2105ext. 2031 > >> >> > >> >> -----Original Message----- > >> >> From: Leonardo Marsaglia <ldmarsag...@gmail.com> > >> >> Sent: Tuesday, March 07, 2023 10:05 PM > >> >> To: Enhanced Machine Controller (EMC) > >> >> <emc-users@lists.sourceforge.net> > >> >> Subject: Re: [Emc-users] OT: Air cooled router spindle problem > >> >> > >> >> [EXTERNAL EMAIL] Be sure links are safe. > >> >> > >> >> 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://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2< > >> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%252> > >> >> > > Fli%2F&data=05%7C01%7Ctoddz%40pgrahamdunn.com%7Ca716ced2cd8b45443 > >> >> > > b1208db1fe039ab%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6381 > >> >> > > 38820129481532%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIj > >> >> > > oiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rj > >> >> > > 6R%2BZb94rpPdzr%2F32kOery9rQ%2Ft47LLFaSdSWYo5h4%3D&reserved=0 > >> >> > > sts.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C01%7 > >> >> > > Cto > >> >> > > ddz%40pgrahamdunn.com%7C7c75dca8021a427b281508db1f821107%7C575854 > >> >> > > 4c5 > >> >> > > 73f47cebee96c3e0806fb43%7C0%7C0%7C638138415730530106%7CUnknown%7C > >> >> > > TWF > >> >> > > pbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX > >> >> > > VCI > >> >> > > 6Mn0%3D%7C3000%7C%7C%7C&sdata=s1%2FMmGIe%2BOIgMMj1IgKv6OTsDFxMuEk > >> >> > > 7ms > >> >> > > t4mMsD%2FGE%3D&reserved=0 > >> >> > > >> >> > Cheers, Gene Heskett. > >> >> > -- > >> >> > "There are four boxes to be used in defense of liberty: > >> >> > soap, ballot, jury, and ammo. 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