On Monday 06 February 2017 08:27:11 dragon wrote: > Tormach has a pretty good white paper on why they chose to use 3 phase > steppers on their machines. I found it a great read for future > reference even though I was going to use servos anyway. > > On another note... you can get E661 servos with encoders off of ebay > for $40 to your door and they are a great match for your Sheldon. Grab > some used servo drives for about $50 each depending on your power > supply situation. That is certainly cheaper than the 3 phase steppers > that you are looking at. Personally if I was to do 3 phase steppers, I > would go with the Leadshine stuff. > > Just my $.10
I see inflation has hit the 2 cents define. :) With shipping added to the $52 they are asking today, about $75 on my front deck. And this guys feedback rating is crap at 85%. The next guy has a 100% rating and wants $65 for it, then $72 something from the last peddler. But zero data, and that model is so old Electrocraft's web search can't find it. So how much twist, what voltage & amps to get that twist, and how long is it behind the mounting face? I don't really have a length limit for Z, but X is not more than 115mm's. IOW, where can I find the info to use it? I am seeing mentions of up to 300 volts and 12 amps, but not in the same advert links. These are brushed motors, can I get brushes? Its also a change to a card to drive servo's, more bucks. As in $80 for a card that slaves 4 servo's to the pwm signals from my 7i90. I assume those +-10 volt signals can drive the amplifiers, but are the encoders position or velocity tachs? Lots of questions I'm afraid, and a bigger bottom line at the end of the probably 3 months it would take to get it all working. Thank you. > > On 02/06/2017 03:09 AM, Gene Heskett wrote: > > Greetings everybody; > > > > I just spent an hour on wikipedia, and another hour reading > > everything that google spits out on 3 phase stepper motors, and have > > not found a convincing argument in favor of 2 phase, other than > > their ready availability. > > > > I can get off fleabay, 3 phase, 230 volt ac powered drivers in size > > & voltages suitable to move this lathe with, for a big buck + an if > > it fits box from the USPO. Those are here, on the left coast. > > > > But no one on this side of either pond is stocking the 3 phase > > version of the motors, and due to their weight, its 2 to 4 weeks, > > and another 56 bucks or so to get any of them because they are all > > in China, so an $80 nema 34 is about $140 on my front deck. Close to > > $250 an axis IOW. > > > > So I need to see a decent discussion on the subject before I cut > > that big a hole in the card. > > > > Many thanks for any educational url's on the 3 phase motors you > > folks can supply. > > > > Cheers, Gene Heskett 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
