What is the winding inductance of the motors? NEMA 17 and NEMA 11 motors sometimes have really low inductance. This causes the current to rise and fall in the windings with each PWM cycle. The result can be heating of the iron due to hysteresis losses.
This can be counteracted by using a lower supply voltage or an external inductor to increase the apparent inductance of the motor. Steve Stallings > -----Original Message----- > From: John Stewart [mailto:ivatt...@gmail.com] > Sent: Sunday, May 26, 2013 2:19 PM > To: Enhanced Machine Controller (EMC) > Subject: [Emc-users] G540, trip pots and stepper motor temperatures. > > I'm getting my little Unimat CNC lathe going, and am doing > axis running > tests; right now working on the Z axis (carriage movement) > > The X axis stepper is sitting idle, the Z axis stepper is > running back and > forth. It is really hot to the touch, and one can smell hot > insulation. > >From what I calculated, this NEMA-11 stepper motor has a > motor voltage of > about 68 volts, running it on 48 volts. (the X axis stepper > is slightly > smaller) > > When it was just sitting, the motor was hot to the touch. > From reading this > list, one might think that running the motor might actually > keep it cooler. > > Anybody know why one stepper motor would be overheating? > > (10mm/sec step rate, not overly fast) > > Yours truly, letting things cool off before trying anything else; > > John A. Stewart. > -------------------------------------------------------------- ------------------------------------------------------------------------------ Try New Relic Now & We'll Send You this Cool Shirt New Relic is the only SaaS-based application performance monitoring service that delivers powerful full stack analytics. Optimize and monitor your browser, app, & servers with just a few lines of code. Try New Relic and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
