On Thursday 02 February 2017 10:29:11 Jim Craig wrote: > On 2/2/2017 9:13 AM, John Thornton wrote: > > I also have an Automation Direct GS2 on my BP knee mill and rigid > > tap with it (need the braking resistor). > > > > JT > > John, > > That is an interesting point. I am getting ready to add gear tooth > sensors on the bull gear so I can rigid tap. I don't have a braking > resistor on my drive. Currently the mechanical spindle brake engages > when the spindle stops via a pneumatic cylinder. To be honest I am not > sure if it would engage during a spindle reversal as I don't do that > currently. It probably would not. Does the rigid tapping cycle stop > the spindle or does it do a reversal without stopping? M3 M5 M4 M5 or > M3 M4 M5?
There is no stop between m3 and m4, so I have had to cobble up some hal stuff to ease the violence of the reversal that Jon's PWMservo driver can do. Other wise it breaks drive parts on TLM. I also slow that on the G0704 in order that Z can keep up with it. I've about 1/2 second of delays there. Experimentally, the reversal this "fake" vfd can do can be unbrutalized, but it takes a minimum HZ setting lower than would be safe for the motor over an extended time period to make it really smooth. The problem is the stopping DC braking is either not effective, or damed brutal from 300 motor shaft revs. > I figured that the drag from tapping would stop the spindle pretty > quickly without the resistor. I would like to hear more about your > experience with this situation. VFD's are 4 quadrant controls Jim, as is Jon's pwm-servo amp. They have as much power slowing the motor as they do speeding it up, until the rotating field is too slow in the vfd case, 10 hz perhaps, then they can put some dc thru the coils to finish the stop. Its a balanceing act to get that right. The vfd can handle that, but with the servo amp, I don't allow the reverse to go on thru to the controller until the encoder says its been stopped for a couple milliseconds. I may do a similar thing on this Sheldon, but I suspect the vfd can handle that good enough. > Thanks, > > Jim > > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
