Kirk Wallace wrote: > On Wed, 2007-12-26 at 21:07 +0000, Lester Caine wrote: >> Kirk Wallace wrote: >>> On Wed, 2007-12-26 at 17:22 +0000, Lester Caine wrote: >>>> Geert De Pecker wrote: >>>>> I probably wrongly assumed that the voltage should come from the KBIC > ... snip >>> How much adjustment will the potentiometer give? Thanks. >> http://cnc4pc.com/Tech_Docs/C11G_&_SIEG_X3_Electrical%20storybook.pdf >> Check out page 7. >> The thing to remember here is that the motor control pot on the Asian mills >> is >> at mains potential, so you need a totally isolated supply to drive that bit >> of >> the circuit. The boards I've played with a have a reasonable range on the >> pot, >> but I've only dropped to +9V from about 11V did not check how much further >> it >> would go. >> >> The NEW boards from cnc4pc don't have the +12V requirement on board, so a >> +5V >> to +12V module may be required. The on board 12V relay has been replaced >> with >> a 5V one so the whole board just runs off 5V now. > > Thanks for the information. Does that mean there is a high common mode > voltage (AC or DC) on the two pins next to the DC converter? Is the > motor controller like the speed controllers for universal motors, or Do > you have any keywords to search on the type of motor controller this is?
YES - basically controllers that only have a control pot on the machine are likely not to be isolated from the main supply, and that is the reason this little isolated control was provided. Controllers that actually have a 0 to 10V DC input are more than likely not to require additional isolation as the controls are already earthed (and in which case the isolated +12 can be dropped altogether - just provide an earthed +12V). It is just the motor controllers that do not provide an 'official' DC control voltage that need care. -- Lester Caine - G8HFL ----------------------------- Contact - http://home.lsces.co.uk/lsces/wiki/?page=contact L.S.Caine Electronic Services - http://home.lsces.co.uk MEDW - http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/ Firebird - http://www.firebirdsql.org/index.php ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
