Is the drive train self locking, so that if you loose power, the load does not drop? Or do you have a brake on the motor or someplace else?
One thing I have heard that can be a problem when using a squirrel cage AC motor like this at very low speeds, is that the motor can overheat due to insufficient cooling because the the fan does not push much air over the motor to cool it. That is why many specialty motors that are designed to run at low speeds, have forced air cooling via a separate motor driven blower. Is the motor encoder tied into the Delta VFD also? With most brands of VFDs, in order to run in true "Vector mode", they need encoder feedback.. Delta says the C2000 runs in FOC (Field oriented control) which I have never heard of before. Dave On 3/24/2014 11:08 PM, Leonardo Marsaglia wrote: > Thanks Dave! > > If I remember correctly the encoder is 2500 PPR. It's a lot for the kind of > job as you say so I'm pretty happy about the way it behaves. > > Anyway, I think that may be using a timing pulley the ripple could be > reduced. It appears only when the axis is going up and between 3000 mm/min > and 8000 mm/min because of the high torque demand. Going down it's really > smooth at any speed. The curious thing is that if I connect only the VFD > and I drive it manually up I don't have any kind of ripple. That's why I > think the solution has to be on the PID and the way the torque is applied > to the screw. > > The good thing is that the machine can work this way and I can improve it > on the go. > > I'll be uploading more videos an pictures when it's done and heating some > parts! > > > > > 2014-03-25 1:19 GMT-03:00 Dave Cole <linuxcncro...@gmail.com>: > >> For what you are doing, that looks really good! >> >> Nice work! >> >> What resolution encoder do you have on the motor? >> >> Dave >> >> On 3/24/2014 7:51 PM, Leonardo Marsaglia wrote: >>> Taking back to life this topic. >>> >>> I just uploaded a crappy video (sorry for the quality it was filmed with >> a >>> cheap phone) that shows how the positioning system is working. >>> >>> Here's the link: https://www.youtube.com/watch?v=Rv2Y9xEkwpI >>> >>> I think in the not so far future I'm going to replace the 2:1 spurs that >>> drive the screw with a heavy timing pulley to reduce the torque ripple >>> during the acceleration. I also thought about upgrade to a permanent >> magnet >>> AC motor but for now I'm satisfied. >>> >>> It's important to say that the chariot weights more than 60 kg and it's >>> working vertically so the results are great. The following error here was >>> set high but as you this is for induction heating so there's no need of >>> high accuracy. >>> >>> Hope you enjoy it, I'm going to upload a better quality video soon with >>> more detail about the motor and the machine! >>> >>> >>> Thanks as always! >>> >>> Leonardo. >>> >>> >>> >>> 2013-12-13 11:32 GMT-03:00 Gene Heskett <ghesk...@wdtv.com>: >>> >>>> On Friday 13 December 2013 09:07:06 Gregg Eshelman did opine: >>>> >>>>> On 12/12/2013 3:26 PM, Leonardo Marsaglia wrote: >>>>>> 2013/12/11 Dave Cole <linuxcncro...@gmail.com> >>>>>> >>>>>>> It sounds like you are greatly simplifying the machine. An MG set >>>>>>> (motor generator set) is a very old technology to create DC power. >>>>>>> That was probably obsolete when it was installed. >>>>>>> >>>>>>> Yes indeed, I really don't understand why a 70's machine would use an >>>>>> motor generator to feed a DC motor. >>>>> For the early variable speed DC motor drives, Monarch and some other >>>>> lathe manufacturers used a 3 phase AC motor driving a DC generator to >>>>> power the DC motor. >>>>> >>>>> There have been more than a few people hook those up to rotary phase >>>>> converters. >>>>> >>>>> Single phase AC motor driving a three phase AC generator, powering the >>>>> three phase AC motor, driving a DC generator, powering the DC motor. >>>> Such complexity in big iron is crazy, and crazy expensive too, if your >> hp >>>> requirements are reasonable. Empire electric, someplace in WI, can sell >>>> you a 0-10 volt analog input control for a dc motor, runs on the 127 >> volt >>>> powerline, and can deliver 25 amps if your circuit breakers can, all for >>>> about $150. Needs about 2.5" of height above a nominally 6x6" open >> frame >>>> plate, which is grounded. Hide it anyplace handy. >>>> >>>> That will power a honking big 4 or 5 hp treadmill motor (see ebay) >> cleanly, >>>> cool & absolutely silently. All in ultrsonically switched hexfets, so >>>> essentially zero heat. These motors aren't "dressed for the party" but >>>> appear to have only one failure mechanism, worn out brushes. They are >>>> quite good sized, so that will take quite a while. >>>> >>>> Laying on the table turning 10k or more revs, you can't hear anything >> but >>>> the fan pulling cooling air. >>>> >>>> I have one running a 1.5hp treadmill motor with a 9 amp circuit breaker >>>> that has only been tripped a couple times, I had miss wired one of my >> ice >>>> cube relays. >>>> >>>> Cheers, Gene >>>> -- >>>> "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> >>>> >>>> Help! I'm trapped in a Chinese computer factory! >>>> A pen in the hand of this president is far more >>>> dangerous than 200 million guns in the hands of >>>> law-abiding citizens. >>>> >>>> >>>> >> ------------------------------------------------------------------------------ >>>> Rapidly troubleshoot problems before they affect your business. Most IT >>>> organizations don't have a clear picture of how application performance >>>> affects their revenue. With AppDynamics, you get 100% visibility into >> your >>>> Java,.NET, & PHP application. Start your 15-day FREE TRIAL of >> AppDynamics >>>> Pro! >>>> >> http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk >>>> _______________________________________________ >>>> Emc-users mailing list >>>> Emc-users@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>> >>> >> >> ------------------------------------------------------------------------------ >> Learn Graph Databases - Download FREE O'Reilly Book >> "Graph Databases" is the definitive new guide to graph databases and their >> applications. Written by three acclaimed leaders in the field, >> this first edition is now available. 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