Need Help!- What's going on here ??

[oilyamerican]

I have a '94 vintage VF-3 that has been running pretty well since I got it last fall.
When my operator came back from lunch break on Friday,the machine showed a 162 alarm when he went to run a part.
This says something about the Y-axis over current or drive fault.
I pulled the way cover off to make sure the ball screw was free,which it was.
I looked in the back for any tripped switches but couldn't see any.
I looked at the drive motor and everything looked normal.
Since the axis drive cables were interchangeable,I swapped the X and Y to see if anything would change.Upon startup,the machine posted a 162 alarm for the X axis.
So am I too surmise there's something wrong with the Y axis motor ???
How could this conk out when just sitting there not doing anything ???
What can I check in the motor ??
It appears to have brush caps; could the brushes be bad ???
Thanks for your time and input !

[gizmo_454]

I will tell you up front, I certainly no expert and I cannot tell you exactly what is wrong. But from what you are describing above, I am going to venture that there is little wrong with the axis motor. Since you swapped the cables around and the error changed from y to x, I am going to say it sounds like either a cable, or an amplifier. Another thought I had was to check the fans cooling the amplifiers to make sure they are working properly. We had 2 stuck fans on our VF2SS we just got in and it threw overheating alarms just sitting there. Again, I am by no means an expert. Just my 2 cents.

Good luck!

Mike

[Al_The_Man]

Surely if it was a drive it would have given the same axis fault, providing the cables changed were to the motor, if so then the Y axis drive is still the Y axis drive, even after cable swap out.
If the cables were from controller to drive, then that changes things.
How long ago were the brushes checked?
They can be removed for inspection and the comm inspected through the brush holder.
Carbon dust should be cleaned or blown out after several years use.
Al.

[Donkey Hotey]

Originally Posted by Al_The_Man How long ago were the brushes checked? They can be removed for inspection and the comm inspected through the brush holder. Carbon dust should be cleaned or blown out after several years use.

This.
First.

[oilyamerican]

Hi All,
First, let me thank you for your input.
It sent me in the right direction.
What happened was that there was a humongous carbon track on one the insulated brush holders.
For those of you old enough to remember the black plastic distributor caps and coils of yesteryear,you know what I mean.
Except this was 10x bigger than any carbon track I ever saw on a distributor cap !
Anyway,careful scraping and washing out with CRC electronic cleaner did the trick.
I coated the spot with electric motor sealing lacquer,so it should be good for a few more years.
I was so thankful that I didn't have to buy another motor as my wife is fighting breast cancer and I don't need to shell out big $$ if I can get around it.
Now I need to figure out how to get the return margin error eliminated,so the machine doesn't alarm out on start up.
If somebody knows how to get in the system and straighten that out,I'd be much obliged.

[oilyamerican]

Oh,I forgot to mention it.
I don't think this motor was ever apart since 1994.
At least judging from how tight all the screws were and the amount of "patina" on the housing,it didn't look like it.
And if it wasn't,that was pretty good service.

[Wizzard of H]

If you are now getting "Y zero return margin too small" that's probably because the motor was removed and re-mounted clocked a little differently. That should not happen for keyed motor shafts but could be caused if you also removed the encoder from the back of the motor. Parameter 126 can fix this either way. It is "Y grid offset". A value of 0 to 8000 is normal. Simplest is to add 4000 if less than 4000 already and subtract 4000 if already over 4000.