Gene Heskett wrote: > > Somebody thinking "outside the box", and making perfect sense. The only > fly in the soup is the 10,000 step encoder, and servicing it at 200 rpS to > get that 12,000 rpms If you run a stepper motor at 12,000 RPM, it will burn up in minutes. You can spin a typical stepper with the spindle motor, and above 1000 RPM it will get very hot with no current at all in the windings. That is all iron loss. 12,000 RPM will require insane voltages be applied to the drive, several hundred Volts. A typical stepper may generate 50 V at 1000 RPM, so that would require a 600 V supply just to equal the back EMF at 12K.
Oh, but then cogoman said : "the stepper motor could be designed with less steps per rev. " Yes, then why make it a stepper at all? How about an 8-pole brushless servo motor? These work GREAT, used by Fanuc since the late 1980's, and now available from many sources. I make affordable servo amps for brushless motors, and have one on my minimill. You do need to get rotor position info from the motor, most small ones have Hall sensors that you connect to the servo amp. I use 500 cycle/rev encoders on mine, that is quite satisfactory. Jon ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
