On Sat, 2008-01-12 at 00:01 +0000, Steve Blackmore wrote: > I use KBIC speed control on my mill, I simply reverse the DC output > using a 20A DP/DT relay.
You don't switch it while the motor is running, do you? The KBIC manual says that you will damage the controller by doing that. I have had another look at the schematic and I am thinking that if you disconnect the armature, you will get a voltage spike high enough to cause SCR1 to conduct in reverse. If SCR2 is on, which is likely, you will have a direct short between the mains, L1 and L2. I think if inhibit is invoked long enough ( 20ms ?) to insure that both SCR's are off, switching the armature will be okay. I just won't know for sure until I try it. Which will have to wait until I get the parts to fix the controller due to my last experiment. > The only thing to beware of when using computer control via a 0-10V > input is the -ve on the KBIC is referenced to mains neutral, and unless > you use an isolated step/dir to 0-10V converter like the CNC4PC C6 > variable speed control board, your likely to blow something. I am looking at an ADC5290 serial digital potentiometer with opto-couplers on the inputs. > There are wiring diagrams on CNC4PC's site and there is a warning in the > manual that says use ISOLATED reference voltage. > > If you want to you could use a KBCC-R model if you want true dynamic > braking and reversing. > > Steve Blackmore I am playing with ideas on how EMC could be used to enhance what people already have. These KBIC controllers seem to be quit popular. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
