2012/1/12 andy pugh <bodge...@gmail.com>: > On 12 January 2012 11:49, Viesturs Lācis <viesturs.la...@gmail.com> wrote: > >> How big was that motor? > > It was a 2HP motor. On reflection, I probably drained the capacitor > and then bad things happened.
How do I determine, what size capacitors should be used? Right on the rectifier and also for those boot-strap capacitors? >> BTW did You have something for the current sensing and over-current sense? > > I think I just put in the minimal components to make it wake up. > What is that on the upper right corner? https://picasaweb.google.com/108164504656404380542/Gibbs#5471910659108799346 > The gates are AC-coupled through capacitors. So, DC power supply > voltage is connected to V+ and the PSU gnd to the three VR(U/V/W) > lines. Typically through current-monitoring shunt resistors. Some > variants of the IRAMS chips have the shunt resistors built in. Ok, thanks, now it makes sense! Do I need those shunt resistors for normal operation of the chip or are they meant just for feedback to controller? > Vss is the logic ground. Ok, great! Is it supposed to receive any additional 5V, 12V or something similar for logic power? > I don't think you want to connect the logic and PSU grounds in this > case, especially if VR is rectified mains. That might actually be > where I went wrong, on reflection. Agreed on that. Page 4 of the manual is telling something about the offsets of voltage, but I have only small clue, what exactly is that all about. > (Freewheel diodes) >> Thanks for the explanation, but I do not get, where to look for them? :) > Yes, on the datasheet, each of the 6 IGBTs has a diode in parallel with it. Ok, found them. So does it mean that it already is protected? Viesturs ------------------------------------------------------------------------------ RSA(R) Conference 2012 Mar 27 - Feb 2 Save $400 by Jan. 27 Register now! http://p.sf.net/sfu/rsa-sfdev2dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
