On 3/4/23 19:10, Leonardo Marsaglia wrote:
Yup, I agree with Gene, if the motor was not spinning AT
ALL, but the VFD or motor was making a whining sound, it may
mean the VFD was only powering one phase winding.
That would indicate a VFD failure. Did you unplug anything
while waiting for it to cool? Maybe there was a bad
connection. Anyway, either a failed winding or a failed VFD
would be fairly unlikely to just recover on its own, so
that is odd. I did have some brushless servo drives on my
pick and place machine give crazy failures but then start
working OK after a power cycle. Eventually, they failed
outright. My guessed diagnosis was the firmware ROM was
going out, and eventually it caused a power on self test
lockout.
Hi Jon,
I didn't unplug any wire but I did cut off power to the VFD to see if
anything changed. I also checked all the wiring and nothing was loose
neither on the VFD side nor the spindle side. Could it be coincidence that
this behaviour seemed to be solved when I let the spindle cool down?
By the way, I forgot to mention. I usually attach some 3d printed impellers
to my collet nut to extract more powder when I machine MDF. Today one of
those just destroyed itself. I wasn't worried about that because it was no
big deal today, It happened before and in a more spectacular way than
today, but now I'm thinking the inertia of the impellers blowing into
pieces could have damaged a bearing? A snapped carbide bit could do this
too? I must point out that all this impeller setup is enclosed with a thick
plastic suction cover so when the impeller breaks it doesn't fly all over
the place.
But this raises the question. Could a bearing be a little bit damaged that
it's not that noticeable when cold and I spin it by hand, but when it
starts to work it gets really hot and adds up more torque to the motor
until the VFD starts to slip and eventually fault itself? I'll check
tomorrow if I can notice a substantial difference between hot and cold
spindle when spinning it by hand because I don't remember it.
I could scope the output of the VFD. I only have two channels available so
is a PITA, but I can try and wait for something strange to happen and see
if the signal is the problem.
I attached a picture of the spindle setup so you can see what I'm doing.
This worked well for months so I'm little lost on where I can start to
track the problem.
El sáb, 4 mar 2023 a las 20:35, Jon Elson (<el...@pico-systems.com>)
escribió:
On 3/4/23 14:08, gene heskett wrote:
Yup, I agree with Gene, if the motor was not spinning AT
ALL, but the VFD or motor was making a whining sound, it may
mean the VFD was only powering one phase winding.
That would indicate a VFD failure. Did you unplug anything
while waiting for it to cool? Maybe there was a bad
connection. Anyway, either a failed winding or a failed VFD
would be fairly unlikely to just recover on its own, so
that is odd. I did have some brushless servo drives on my
pick and place machine give crazy failures but then start
working OK after a power cycle. Eventually, they failed
outright. My guessed diagnosis was the firmware ROM was
going out, and eventually it caused a power on self test
lockout.
Jon
Don't leave the probes connected more that a very few seconds, that 380
volts is well above the rating of the resistors used in 10x utility
probes. I destroyed several genuine tek probes leaving them hooked up
watching for intermittents at working voltages below 250. I did
eventually pin the problem down to a 1 uf goodall brand capacitor that
was intermittently killing the video in an RCA TT25DL tv transmitter. I
wasn't so "good" after "all" :o)>
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
