Hello! Recently I have posted some questions about the retrofit that I am working on and now I have encountered an issue that I cannot figure out. The thing is that I am swapping original Yaskawa servo drives with Mesa 8i20. One of the things for that was 3phase rectifier bridge (it takes 230 VAC input and provides 340V output) and 4700 uF capacitor for smoothing the ripple. It took me some time and some patience from PCW to fix the config and in the end I got one 8i20 to move one joint in the machine. So my next step was adding 2 more 8i20 drives for remaining 2 joints. It ended up with a blast in one 8i20. So I replaced it as well as I had to replace rectifier bridge. But now my issue is that protection fuse is tripped as soon as I enable machine power. 1) only rectifier bridge connected - all good 2) rectifier bridge + capacitor - fuse tripped immediately Note that I have not yet connected DC bus to 8i20 drives. I checked capacitor with multimeter, it was showing 180V DC (and it did not decrease in that time that I was holding multemeters pins there). I am not sure if that is some residual charge from previous (which I doubt) or if that was some charge that was acquired before fuse was tripped, but this seems to me like a good capacitor. Is that correct?
I do not understand why was everything fine in initial testing - I did turn machine on and off lots of times and capacitor was discharged (and recharged!!!) numerous times. I have swapped that fuse for identical unit from a machine that has yet to go through the retrofit process. And it is the same. So my question to electronics gurus - could capacitor be damaged or was it just a beginners luck that everything worked and do I need to introduce some inductor between rectifier bridge and capacitor to limit the startup current that charges capacitor? Viesturs _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
