Regardless of code provisions; From a practical standpoint I would install a two pole breaker in the lathe control box, so you can disconnect the power at that point without going to the plug or house/garage breaker to disconnect the machine. You should also have some Estop/Big red stop button provision for your own safety. J class fuses are current limiting fuses designed to limit the amount of energy available when a short circuit or ground fault occurs. They are commonly used in factory machines to limit damage when an electrical fault occurs. However house/garage wiring in the US can't deliver that much energy so current limiting is really not a concern. Class J fuses are also very expensive. A two pole 10 amp Curve D breaker can be cheaper than one class J 10 amp fuse.
http://www.fusesunlimited.com/Products/ClassJFuse/ Automation Direct has good prices on two pole breakers in the US but there are also many other sources. A line filters prior to the inverter is used to prevent interference between the drive and everything else you have in your house/garage. Inverters can be extremely noisy and can really screw with things such as computers, like your LinuxCNC computer! You really want to use a line filter. Dave On 11/1/2016 8:42 AM, Todd Zuercher wrote: > No, it is not overkill to fuse both (or all 3 with 3 phase) "hot" lines, it > is code. > > ----- Original Message ----- > From: "John Alexander Stewart" <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Sent: Tuesday, November 1, 2016 8:33:39 AM > Subject: [Emc-users] Question regarding fuses, line reactors > > Hi all; > > Back to my CNC lathe project; it has sat dormant for a few years now. > > Opinions wanted: > > The VFD suggests 10a external fuses, plus a line filter. I'm running this > on 240v, over here in North America. > > Are 10A slow blow 250v glass fuses ok for this application? Is it overkill > to fuse both hot leads, I presume so, but if I'm going to the bother of > putting in 1 fuse holder... Also, I could use class J fuses, but note that > glass fuses seem to be just fine for other workshop equipment. > > Line Reactors. 10A. Generally a good idea or not really worth worrying > about? > > The 3-phase from the VFD will be in a metal braid for shielding, grounded > at the VFD end. The 4-wire cable will have the U-V-W + ground, weird to > ground both the VFD side and the motor, but that's the way it's done, I > guess. > > The lathe is an 8x18, Austrian made lathe. Would have loved a Tormach, but > the size of the thing would mean a new house, and *that* gets expensive. > > Thanks - John. > ------------------------------------------------------------------------------ > Developer Access Program for Intel Xeon Phi Processors > Access to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today. http://sdm.link/xeonphi > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ > Developer Access Program for Intel Xeon Phi Processors > Access to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today. http://sdm.link/xeonphi > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
