On Wed, 8 Sep 2021, Todd Zuercher wrote:
Date: Wed, 8 Sep 2021 20:56:27 +0000
From: Todd Zuercher <to...@pgrahamdunn.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] VFD Issues
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
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Is it possible the brake voltage is set too low so its
stuck-on at your nominla line voltage?
Peter Wallace
Mesa Electronics
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