> > > Date: Fri, 26 Jul 2013 14:44:28 +0100 > > From: andy pugh > > <[email protected]<https://mail.google.com/mail/u/0/?view=cm&fs=1&tf=1&[email protected]> > > > > Reply-To: "Enhanced Machine Controller (EMC)" > > > > <[email protected]<https://mail.google.com/mail/u/0/?view=cm&fs=1&tf=1&[email protected]> > > > > To: "Enhanced Machine Controller (EMC)" > > <[email protected]<https://mail.google.com/mail/u/0/?view=cm&fs=1&tf=1&[email protected]> > > > > Subject: Re: [Emc-users] Two phase BLDC motors > > > >> I need to drive rare 2-phase BLDC motors, 60V 22A. Is there a suitable > MESA > >> hardware for LinuxCNC? > > > > What does the excitation pattern look like? > > > >> Though I guess bldc comp is meant for 3-phase motors. > > > > It is, but as it is a ".comp" it is easy to modify. >
That sounds great. There are servo drives with external commutation so there's a chance. > > > The 3-phase excitation pattern is encoded in a 2-digit octal constant. > > The binary bits correspond to Ah Bh Ch Al Bl Cl > > > http://git.linuxcnc.org/gitweb?p=linuxcnc.git;a=blob;f=src/hal/components/bldc.comp;h=20c882ed95966d2b727e8b402b1e639907d22b85;hb=94d3babf892e2680714696df05ead32cace79c83 > > Line 402 is a comment showing the hall pattern. > > The next 47 lines cover every possible mapping from a hall pattern to > > a phase pattern. You would only need to consider one pattern. > > > > 024 means: > > 0 = Octal Constant > > 2 = 010 binary, ie Phase B high > > 4 = 100 binary, ie Phase A low. > > > > I don't think that this scheme will work for a 2-phase motor as I > > suspect it has 4 wires, so there aren't enough bits in octal. > > > > -- > > atp > > If you can't fix it, you don't own it. > > http://www.ifixit.com/Manifesto > > > > > 2 phase motors normally have sine/cosine drive (like a step motor) so if > BLDC > had a phase offset parameter (default 120 degrees, settable to 90) 2 phase > motors could be accomodated. (ignoring HALL patterns if such things exist > for > 2 phase PMSMs) > > That is correct, the manual says about sinusoidal commutation with 90 degrees phase offset. No Halls. Is there any way (assuming blcd comp is modified for 90degrees) to use 3-phase external commutation drive like AMC S60A40 or even 7i39 (just to test if it works)? Like connect one winding to AB output and other to BC. Does 7i29 > Is 22A peak or continuous? If continuous it may have a 70A or more peak > current rating! > > I guess it's 22A continuous and 220A absolute peak, that's what the specification says. But these are custom frameless motors and the continuous current depends on cooling conditions. Other table says about 100degrees temperature rise for 12A continuous current. So it looks like 50A peak is quite enough. Andrew ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
