> Could you give me some idea of what the advantage is of using 2 and 3 > > stack steppers? Perhaps I'm in over my head here, but I'll share what I think I know. The tendency for 2 to 3 stack steppers is for the magnetic circuit inside to get too long, and create high inductance for the amount of field strength it produces. This limits the top speed of the stepper (the assumption here is standard 200 steps per rev steppers). There's a point where stepping up to a NEMA34 from a NEMA23 will get the torque needed with less inductance, which allows for more speed. This, is more theoretical than practical, since it is quite possible to design a slow stepper in both NEMA23 and NEMA34 sizes, and many do just that. While a fast stepper motor needs to have less than 3 mH inductance per coil, I have seen even small steppers with over 10 mH.
Rexstep stepper motors <http://www.homeshopcnc.com/index.php?option=com_virtuemart&page=shop.browse&category_id=1&Itemid=1> and usa stepper motors <http://www.usautomation.com/StepMotors.aspx> seem to have low inductance per torque, assuming you can trust their specs. This one <http://www.mpja.com/62V1A18-Deg-NEMA-23-Step-Motor/productinfo/17455+MS/>, and this one <http://www.mpja.com/78V2A18-Deg-NEMA-34-Step-Motor/productinfo/17457+MS/> seem to have too much inductance for fast operation. So practically speaking, you need to evaluate each motor separately. ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
