Hi Gene, > From: Gene Heskett [mailto:ghesk...@shentel.net] > On Tuesday 08 December 2020 02:04:49 John Dammeyer wrote: > > > > I think I'd be measuring the ohmage and inductance of each winding > > > in that motor. A partially shorted winding would be on my suspects > > > list. > > > > > > They should match within a few %. A 10% diff would condemn it in my > > > CET mind. > > > > > > Cheers, Gene Heskett > > > -- > > > > Thanks for the suggestion. > > I'll check that too although I'm leaning to epoxy PC board material > > converted to conductive carbon.
Unfortunately I can't see which transistor pins go to which terminal pins. But it appears there isn't a lot of conduction between the winding pins since without the motor connected nothing gets warm. The winding resistances are the same and actually motion is quite smooth. But with the 58.5VDC toroidal power supply meant originally to run a 4 axis stepper conversion there's lots of power there to create the specified current. Now assume for example it's 7 amps and the motor measures at 1.2 ohms on each winding. That's 8.4V steady state across the winding or 58W in the motor. Now we know of course the chopper design will apply the 58V for as long as needed to maintain say the 7A at the top of the micro-stepping curve. So assume we have 2 ohms DC resistance in a now burnt traces in between layers. With 7A through that 2 ohms there's a 14V drop. Not a big deal with the 58V supply. But 14V and 7A is 98W. Easily enough to slowly raise the temperature. And for all I know the resistance is even higher. I hit ESTOP which removes DC power. Plugged the motor back in. ESTOP off and the reflective temperature probe shows the bottom pin of the connector quickly reach 40C from 22C. During all this time the motor itself is barely warm. A far east stepper driver rated for up to 110VDC and 8A is on the way. Be here next Wednesday so then I can verify that it's the driver. And no answer back from Gecko. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
