On Wed, 6 Apr 2011, andy pugh wrote: > Date: Wed, 6 Apr 2011 14:18:18 +0100 > From: andy pugh <bodge...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: [Emc-users] PSU > > I have 400V servo drives, 350V motors and 240V single-phase mains power. > > Is there any reason that my servo power supplies need to be anything > more than a rectifier and caps? I will probably add a PTC and an input > fuse too.
If this is for 8I20s, a bridge rectifier and a filter capacitor running off 240VAC is fine. Usually designs include a NTC thermistor to limit the power-on current surge when the capacitor voltage is 0. Fuse should go in the AC line. A bleeder resistor is needed as well, even if you have a relay. > > Would a relay/resistor to discharge the caps on power-off be usual? Yes, this is faster than the bleeder, and if turned off in e-stop, can brake your servo drives (which is normally a good thing). Chose a time constant such that the deccelleration of the motors will not be faster than your fastest acceleration time from 0 to full RPM on your servo drives. Too fast a PSU voltage drop when the motors are spinning fast may damage the IGBT module, as the braking current in this situation flows through the IGBT modules diodes and is not limited. > > -- > atp > "Torque wrenches are for the obedience of fools and the guidance of wise men" > > ------------------------------------------------------------------------------ > Xperia(TM) PLAY > It's a major breakthrough. An authentic gaming > smartphone on the nation's most reliable network. > And it wants your games. > http://p.sf.net/sfu/verizon-sfdev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Xperia(TM) PLAY It's a major breakthrough. An authentic gaming smartphone on the nation's most reliable network. And it wants your games. http://p.sf.net/sfu/verizon-sfdev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
