Tom wrote: > Jon Elson <el...@...> writes: > > >> Oh oh! ... >> >> The Excellon drive may have had one motor pole grounded, and that may be >> tied to frame ground. Certainly not a great scheme, but they all seem >> to use 3-wire cables. I know my motor is completely floating, but that >> doesn't necessarily apply to any other unit. >> > > Hi Jon, > > This is an Excellon quiet drill 1010. It has four motor leads, one of which is > connected to the motor housing (I assume it is gnd). I checked the motor phase > leads after my "incident" and all had matching impedances and none were > shorted > to ground. I did not hook the 4th ground lead to the vfd gnd, my bad :-( > BTW, I am using a Danfoss vfd to power the Excellon spindle with very good > results. The Dandfoss has an upper frequency limit of 1000Hz, which is not as > high as an Excellon drive, but works well for the money. > I have an exceedingly old Westwind spindle off an Excellon PCB drill from the late 1960's, I believe. (It came with a GE NC controller with Germanium transistors that predated the Mark Century line.) It only has a 3-wire cable, with IEC colors, although the grn/yel striped wire is NOT ground. Maybe it would have had the same problem, but when I use it it is bolted to my Bridgeport quill, and so gets a poor ground through the Bridgeport frame. I will add a ground wire before I use it again, as I don't want any ground currents going through bearings. What model Danfoss drive is that? I found an AC Tech drive that also will go to 1 KHz, but that is a special-order option.
Jon ------------------------------------------------------------------------------ Check out the new SourceForge.net Marketplace. It is the best place to buy or sell services for just about anything Open Source. http://p.sf.net/sfu/Xq1LFB _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
