If you have not purchased the VFD yet the Automation Direct GS2 series can be controlled directly with LinuxCNC via the serial port. That is what I have on my BP. Can't wait to fit the encoder...
John On 10/19/2012 4:47 PM, Greg Bentzinger wrote: > > I am converting a cnc knee mill from 3 phase to single phase. > > The spindle is 3hp (2.2kw) and I am fitting a VFD in place of the HD relays > that just turned the power on in FWD or REV. > > Speed will not be controlled directly by the VFD, only direction. The mill > (Hurco KM3P) uses the common Bridgeport style variable drive pulley system > and has a motor to adjust the pulleys while reading a tach for verification. > After speed is set it is not monitored. This is how the current control > (Hurco Max32) was designed, and for now I am retaining this control and NOT > doing an LCNC conversion. > > Others have done this with the KM3 model which does not have the programmable > speed function and it has worked great for them. I only have 1 burning > question. This machine can do near rigid tapping. I have floating holders > that only have about .09" total movement. The machine now taps by a G84 type > action and the control reads the tach and spots the zero crossing point of > the spindle reverse and ramps feed by the tach. Not perfect - but close and > great for its age. The regular KM3 does not have the tach function and needs > a float holder with more travel. > > My problem is this - with site 3phase power you can throw a motor running > forward into reverse and it just does it. I'm sure the control has a ever so > slight delay between relay actions to allow for mechanical times to prevent > switching "shoot through" but I have no idea what this delay is. I don't > think I can just switch direction on the VFD without first going through a > breaking action. For any other action the machine would just open the relay, > let the motor coast down for 6 seconds then apply a spindle air break to lock > the spindle. E-stop drops the relay and applies the break instantly. > > I am using a Teco FM50-203-C and I also have the optional breaking resister. > I would prefer to let the motor coast and just reverse it for tapping but I > don't know if a VFD can take that kind of repeated abuse - lots of tapping. > > So - do I need to hook up the breaking resistor and have it set to break the > motor in under a second? How would the VFD be setup under LCNC to do > tapping? - I watched Ander's rigid tapping videos and it looks like it is > reversing at full programmed speed. > > I'm trying to be as gentile and least excessive waste heat generation in the > components as I can while getting the usable function. > > BTW - I've been dying for a chance to make it over to MPM for a visit, I am > committed to a trip to the left coast in early May but I sure hope I can > escape again in June. I'm just next door in Colorado. > ------------------------------------------------------------------------------ > Everyone hates slow websites. So do we. > Make your web apps faster with AppDynamics > Download AppDynamics Lite for free today: > http://p.sf.net/sfu/appdyn_sfd2d_oct > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
