X axis fault

[voytek1]

Hi there,

The machine is:

Fadal VMC-15
Model #: 914-15
Year of mfg: 1997
Serial #: 9708670

Spindle motor: Baldor 10HP, 3ph
Spec.: 37F71800073 X073 X173
Frame: 215TC,
Volts: 230/460

This machine is always on.
While trying to clean up the interior I noticed that the monitor displays “ X Axis fault” “Error 18”.
In MU function on page 43 it only says “Amplifier fault on axis”
I could not put the machine in Cold Start position. I shut it down anyway. When attempting to turn it on
again I canceled the first screen and Jogged Z axis to Z=0 and Y=0 with success.
However while attempting to Jog X axis to home position I got the same message “ X Axis fault” “Error 18”.
I opened the side enclosure where the controller cards reside.
The cards in slot 9, 10, 11 show only red blinking LEDs.
I believe that it means they are OK.
I noticed that there are also three cards in right upper section of the enclosure. Next to large capasitor.
These cards seem to be not removable.
What are those cards?
On two of dose cards there are green LEDs but on the first card from the left the LED is dark.
I also checked the breakers in back enclosure by depressing the white buttons.

Any suggestions?

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[voytek1]

Thinks that happened from my last post.

Today I removed the board that the LED was dark, disconnected the wires from the bottom terminal
and disconnected the orange connector. The board is a Glentek 7377-1002 Power Conversion board.
I examined it even under microscope and there are no visible defects or burnouts on the board.
It appears visually in perfect condition.
On orange connector on the top of the board there are 15 pins with wires on pin 4, 5, 6, 7, 13 and 14 marked with same numbers.
On the black terminal there are four wires. The two from the top marked #3 and #4 that go to the X axis
servo and two on the bottom that are Black and Red go to the large capacitor located to the right
of the three boards.
On the very bottom of the board there is a 20 Amp ceramic fuse.
I removed that fuse and discover that it is burned but without any visible damage.
I replaced it with the good fuse expecting that it will solve the problem.
After turning the power to the machine on I received the same message about Error 18 and an “X Axis fault”.
I checked the fuse and it was burned again.
Then I disconnected the wires #3 and #4 that go to the X axis servo to eliminate possibility that
there is a short somewhere on those wires or the servo.
I installed new 20 Amp ceramic fuse on the board and turned the machine on again.
Machine went into the emergency stop again and shown the same message.
I am assuming that the other two boards ( on the right ) are exactly the same but only for
Y axis and Z axis.
Because the two wires from the black terminal that go to the X servo were already disconnected
and the two remaining wires seem to be connected to the same capacitor ( in parallel ) as other
and the result was the same my conclusion is that the board is bad.
In that case I could use the board from Y axis and if it worked it would confirm that simply X axis
board is bad. However I could destroy it if the problem comes from the wires coming to the orange connector.
That would be expensive test.
Now, my questions are:
1 - Where the wires going to the orange connector come from?
2 – Is it possible that any of them could cause the problem?
3 – Is it safe to swap the boards?
4 – Is it safe to install brand new board?
5 – Could that board go bad on it's own ( eg. just from being old ) or some other thing my
have caused board's failure?

[Tedger]

The Axis control cards are the ones in the slots 9,10 and 11. The picture you have shows the axis Amplifier. There is one for each axis. The control cards rarely fail in my experiance. That means you have a bad amplifier or a bad motor. The amplifiers and motors are interchangable so swap two amplifiers and see if the problem moves to another axis. If you still get an X axis alarm, You have a motor problem. I have never hurt an amplifier by swapping it out with another so I wouldn't worry about that.

[voytek1]

The Axis control cards are the ones in the slots 9,10 and 11. The picture you have shows the axis Amplifier. There is one for each axis. The control cards rarely fail in my experiance. That means you have a bad amplifier or a bad motor. The amplifiers and motors are interchangable so swap two amplifiers and see if the problem moves to another axis. If you still get an X axis alarm, You have a motor problem. I have never hurt an amplifier by swapping it out with another so I wouldn't worry about that.

Hi Tedger and thanks for your reply.
Did you read a second part of my post?
The ceramic fuse on amplifier board gets blown even after disconnecting entire X axis from the card.
Is it not the indication that X axis motor or wires going to it are OK?

[Tedger]

I've never blown the fuse on the amplifier.If your blowing a 20 amp fuse, I wouldn't suspect the control board. Either something in that amp is bad or maybe you have a short in the motor or a short in the motor cables. The X axis motor lives it's life inside the machine so it's usually the one that goes first.
The easiest way to check is swap a board,amp or motor.
BTW - You shouldn't be energizing the amp with no motor hooked up.

[FadalCNC_Com]

I would do just exactly as Tedgr explained. If you have access to a megger, I would Meg the X axis cable and motor and see if it is bad. Anything under 5 meg is generally bad. Exchange the X and Y amplifiers. See if the problem moves, if not, you have an issue with the motor, resolver, cables or controller card. If all the lights on the controller cards are blinking red, this is a good sign they are fine. Make sure all your bullet connectors are tight on the edge of your boards.

If the problem stays with the X axis, replace the motor and see if this solves your problem. If not, you will need new cables. We have all you might need in stock.

FadalCNC.com Tech Support

[voytek1]

I removed the servo for X axis from the machine and performed some tests just to make sure that the servo is not the culprit.
I span the servo motor by hand – no resistance and no detectable noise from brashes.
Spinning the rotor with shortened leads – noticeable braking uniform on 360 degree.
Resistance between the leads approximately .8 Ohm on entire 360 deg.
Resistance between windings and the body of the motor reads more than 130 Megaohms on entire 360 deg.
So my conclusion was that the servo motor is OK.
Now I swapped the amplifier cards for X and Y axis.
The error now is as I suspected: “ Y axis amplifier fault”.
This time I was able to jog X axis to it's Home position.
So my final conclusion is that the amplifier card for X axis died.

On Oct, 4 2018 I replaced faulty X axis amplifier board with brand new.
I can now jog X, Y and Z axis to home position without any problems.
However when I issue CS command I get the following error:

“ X axis fault(s) as follow:
Error #1
Motor overload “

This is what my manual says about error #1:
“This message appears on power up if no motor feedback ( resolver or encoder) or no motor motion is detected by the axis controller.”

I am confused.

[voytek1]

The things sometime are not as they appear.
When I said that I can jog the X, Y and Z axis it is not quite correct.
Jogging the Y and Z axis makes those axis move.
However, jogging the X axis shows on my monitor movement but the table itself does not move at all.
Error #1 suggests that the resolver on that servo does not send any signal or the servo itself is bad.
Since I have no extra servo to try I decided to remove the X axis servo and do some checking.

First thing I did, I removed the brushes (one at the time) and checked for some wear.
They look clean and uniform.
I also measured the length of the brushes.
Those all are of uniform wear and each is 0.54” long.

Second, I checked the condition of the commutator.
All segments are clean and evenly spaced without visible wear or shorts between.

Third, I repeated all the previous tests minus megging.
Then, I removed the cup containing the resolver.
Inside everything looked clean without any traces of coolant or chips or any other contamination.
See attached picture.
By the way, I don't use any water soluble coolant, I use only pure cutting oil (MOBILMET 766) as I work mostly with aluminum.

Fourth, I checked the signal from the resolver on the control card (bottom push connector) while the machine was in emergency stop.
The reading was 1.79 volts which, I believe, is OK.

Fifth, I connected a 20 volt battery directly to the servo after disconnecting it from the amplifier.
The servo rotated in both directions.
Then, I connected a 40 volt battery.
This time the servo was rotating much faster.

Sixth, I connected a 40 volt battery to the wires on the other side of the harness.
The servo was responding by rotating in both directions.
I think it means that there is no short in harness.

Seventh, I gambled and swapped the new board with the Y axis.
Surprisingly now the X axis servo could be rotated in both directions while jogging the X axis.
It would also mean that there is no short of any kind in harness.
However, while attempting to jog the Y axis (with the newly installed amplifier card) it was not moving at all despite showing changing numbers on the monitor.
It seems like the new card does not generate any voltage to the servo or simply is defective.

I wonder when my nightmare will end.
My original card is Glentek 7377-1002.
On site:* New / Better AMP-0006 Amplifiers for the Fadal VMC15 it shows that a direct replacement is I.T.S. AMP 0006i.
However while following the link “Visit For Price” to https://itscnc.com/amp-0006-its-p-11.html the site shows AMP 0006 ITS or on site https://itscnc.com/amp-0006-p-12.html it shows AMP 0006.
There is a little confusion there.* Which one is correct?

My servo motor as I read from the label is Glentek* MTR-0002 Model: GM4050F so as fadalvmcparts.com says
on the site* New / Better AMP-0006 Amplifiers for the Fadal VMC15 the I.T.S. AMP 0006i would be the right one.

Does anyone know if all those cards are correct?
Does anyone know if my logic is correct?