Fanuc 0TC with 409 AL-31 alarms

[bob1112]

We are trying to work through some problems with this new used Mori we have. We are now getting axis motion but as soon as we hit a spindle rotation button on the panel, the load meter shows that is is trying to do something and it just errors out and will not clear without shutting down the machine. The code on crt is 409 and the spindle drive is AL-31. I know the spindle is free but have not verified the motor is good. Unlikely but possible. We get zero movement on the spindle.

When the machine is on, we can manually spin the spindle and it tachs on the drive so the encoder should be ok. What are we missing here? We are suspecting two relays missing right now but thinking they are for simple things like light and turret rotation. Maybe?

We are working to get some tech books for this control so we can get a grip on the hard parts.

[bborb]

AL_31
Motor Speed detection
Motor not reaching commanded speed

[bob1112]

I am pretty sure the encoder or tach works on the motor because we can manually spin the chuck and it will readout on the spindle drive. Could this be a motor failure? What should we look for with this fault? Thanks

[bborb]

Start with the basics. Is the motor getting ANY voltage? The load meter is registering the amplifiers characteristics, find out if the motor is really getting voltage.

[Al_The_Man]

Is this a Fanuc or 3rd party drive? Is it AC motor or DC?
The fact that the drive appears to get the start command, probabally eliminates any condition in the control circuitry, PMC etc, from affecting it,
What you could be seeing is the spindle encoder on the spindle shaft, which works back to the control usually, not to the drive.
If you have a DC spindle, there is a tach on the rear motor shaft, if AC, probabally a digital pulse tach. Usually you would see a tach loss indication if it was these.
You could try disconnecting the motor leads and see what alarm you get when you try and pick the spindle up, 2 leads if DC, 3 if AC motor.
Al.

[bob1112]

The spindle motor and drive are AC and the axis motors are Alpha AC units. I am getting ready to test some leads gong to the spindle motor to see about a motor problem but I bet the motor itself is good. I will also test the spindle drive output with an inrush test to see if I can capture a spike going to the motor.

The spindle drive unit is a Fanuc unit. The entire build on this Mori is Fanuc. Notu sure about the spindle motor but axis motors are as well. I am just hoping the drive is good. Things seem to power up and no codes unless I command the spindle. I am missing a couple relays and we are working to get layouts today to see what is missing but probably nothing to do with thie spindle fault.

Is there a simple way to test the feedback off that spindle motor? Can I easily power up the motor with the drive direct to verify the drive will run the motor? I want to take the control out of the equation if possible. I know with one of our other machines, that is nice to power up the Yaskawa drive and test it as stand alone.

[bob1112]

Ok, I verified the motor is not getting power upon command. Control indicates 115% or something for a couple seconds but no go. The spindle motor is also Fanuc. The spindle encoder is mounted to the side of the spindle with a belt.

I am waiting on those books to show up but I was wondering if I need to home this machine or anything special? Is it something I am doing wrong?
I sure need to try to fire the spindle drive alone manually to verify operation if possible. That would sure help track it down.

[Al_The_Man]

I believe the Alpha units are digital, not like the old analogue controls where you could use a battery box.
Did you disconnect the motor to see what type of fault comes up?
If it is the firing circuit, you may get the same fault with the motor disconnected.
BTW, you aren't running this off of a RPC are you?
Al.

[bob1112]

um, RPC, that is a 10-4. I have verified the control is not using L3 on any leg to ground loads. That should be the only hang up. I would think if voltage was an issue, we would get another code here.

I did not understand what you said about disconnecting the motor. Are you referring to the spindle motor? the motor encoder? Seems pretty simple up there. One motor, and one encoder. I guess maybe disconnecting the encoder might give me something. Where are you going whit that?

[Al_The_Man]

I meant the three phases out to the spindle motor, leave everything else connected.
The low level logic on the drive comes off either two phases or all three, if it is off 2 ph (1 phase transformer) for the low level logic, it could be being fed from the artificial phase.
Al.

[bob1112]

huh, so you are thinking to pull the leads that go from the drive to the motor? If they are not outputing anything, how would that help? I am just trying to understand your logic on this.

Are you thinking the RPC is causing this problem leg?

[Al_The_Man]

Just a question of eliminating as much as possible, its hard to trouble shoot from a distance.
If you disconnect the motor, there is no voltage 'sag' on the artificial leg.
Al.