I'm assuming you always start at the lowest speed and ramp up. Check if you can change the operating mode of the VFD. Some of them can be operated in either a constant voltage mode or a constant current mode, and those values may be programmable. You might need to play around with it some. To get the most torque at low speed you want the max current the VFD can deliver and the motor can take. If the motor can take more than the VFD can deliver you will need a larger VFD-see if you have a locked rotor current spec on the motor. You shouldn't need that much to get it moving, but it gives you a guideline.
If the motor is not turning it means that all the energy going into it is being converted to heat, so do not leave large currents running through the motor for more than a moment as you are testing. Start small and work your way up. Javid ----- Original Message ----- From: "Kirk Wallace" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Saturday, July 07, 2007 2:29 PM Subject: [Emc-users] Tapping and Treading > >From the videos on the lathe threading wiki page: > > http://www.linuxcnc.org/content/view/35/13/lang,en/ > > I can see that single point threading with a normal EMC lathe setup is > doable. But what about rigid tapping? It seems to me, tapping would > require being able to stop the spindle at a precise location. Can this > be done with: > > - A VFD or mechanical braking? > - Use a servo or stepper for the spindle? > - Forget the spindle and use a threading attachment? > - Use some sort of live tool? > > Has anyone used a VFD with EMC yet? I just put one on my manual lathe > and I am having troubles with starting at low speeds. Will low speed > torque always be an issue with VFD's? > > Kirk Wallace > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
