Cathrine Hribar wrote: > > On Sat, 24 Jul 2010 23:18:28 -0400 > Gene Heskett <gene.hesk...@gmail.com> > > > Hi Gene: > > Thanks for explaining the diff. between those DC brushed motors. I understand > most of what u wrote. > > One more question, if u will. > > Is a stepper motor as powerful as a servo if voltage & amp draw are the same? > No. This sounds like a simple answer, but is really a "you can't even begin to compare the two types". A stepper motor produces the greatest torque at standstill, torque falls off linearly as speed increases. A servo motor produces rated torque up to its maximum speed. That's why a stepper can be rated for 100 Watts shaft output, while a similarly-sized brush or brushless motor can be rated for 400+ Watts. The stepper draws current even when standing still, which is just a big waste. The servo only draws current when delivering power to a load.
Another problem with steppers is that they cannot run fast or they overheat. A typical servo motor can be run at 2000 RPM all day with no problem. A typical stepper will burn out if the shaft is spun at 1000 RPM, with no electrical connection at all. The magnetics induces iron losses in the motor and it gets hot. This may happen in as little as 20 minutes! Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
