I was working at upgrading the spindle on a machine. The old spindle was 9kw the new one is 11kw. This is a Yaskawa 626MC5 drive and a 24000rpm 11kw router spindle. At first I tired test running it without adjusting any of the VFD settings. The first test, running a spindle run in program, failed on the first rpm step after a couple minutes, with a VFD over current alarm. I then dug into the VFD settings, and made some adjustments (mostly adjusting the max current settings.) same result. Then changed the base voltage setting, first try I went the wrong way, and that made the current draw worse, so I shut it down right away before any alarms. I then moved the base voltage down, and that lowed the low speed current draw to within the specs for the VFD. Next thing I notice I smell something hot, I quick open up the cabinet and the braking resistor is melting down. The drive is rated for 22.5A and according to its screen it was only outputting about 17-18A and wasn't even braking at the time.
Where did I go wrong? I've ran undersized VFDs numerous times without issue, I thought it just limited your max power. Did I mess something up in the drive earlier when I set the base voltage wrong and the drive was trying to output 30+A? We have a new braking resistor ordered, but what about the drive? I'm afraid to just hook it up and try it, for fear it will do it again. Can I test it without the braking resitor? Todd Zuercher P. Graham Dunn Inc.<http://www.pgrahamdunn.com/index.php> 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
