Is there a reduction? What is the rated rpm? On Mon, Jul 26, 2021, 6:03 PM andrew beck <[email protected]> wrote:
> I would suggest a closed loop ac Vfd drive with encoder. They are > awesome. > > I normally. Buy schiender altivar 71 drives cheap second hand. > > But most brands have them. > > Second option is a open loop vector control Vfd. They are pretty good. > > > > On Tue, Jul 27, 2021, 10:55 AM Earl Weaver <[email protected]> > wrote: > > > Hi, > > I have a lathe spindle with 8 in. chuck that is run with a 5HP Reliance > > DC Motor and Reliance DC Drive. > > I just cannot get much power out of it at low RPM. Was trying to turn > > 8in OD steel, at approx. 200 -250 RPM with .005 in. cut. It didn't work, > > it just stalled. > > When I run it at low RPM the chuck rotation is movable, not firm. > > I can take a hold of the chuck and hold it and move it back and forth as > > it rotates. > > It also is more noisy at low RPM. > > > > This lathe is a Linuxcnc retrofit with J Elson's Universal PWM > > Controller and DAC Spindle control. > > The DC drive has tachometer feedback from the motor. > > I have tried numerous times to adjust, tune the drive, without success. > > I also tried closed loop control from the spindle encoder within LCNC, > > also no success. > > > > So here come the questions: > > Should I keep trying to get this DC Drive working or would it be better > > to switch to AC Variable Frequency Drive? > > If I would switch to AC VFD would 5HP AC Motor be sufficient size for > > existing 1:1 ratio double v belt to drive 8" spindle chuck? > > What torque at low RPM can I expect for this 5HP DC motor? am I > > expecting to much from it? > > Would there be a better drive option for the existing DC motor? > > Any recommendations? > > > > Thanks, > > -- > > Earl Weaver > > Email: [email protected] <mailto:[email protected]> > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
