Fanuc AC spindle Alarm AL-12

[Tero Kaarlela]

Hi,

Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?



Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

[Wayne Weedon]

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led
display shows AL-12(Excessive current on DC-link). Alarm comes when
spindle stop command is issued(M05). Spindle accelerates and runs fine
but every M05 gives this alarm. Machine is Kitamura Mycenter 2X from
1995 with Fanuc 0MC. Anyone had this trouble here? If yes how it was
solved?

If the decel parameter has not been changed to give a faster spindle
stop, I'd be looking at the condition of the braking resistor.

It's possible you have a broken cable there.

Wayne....

[Bart]

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

I agree with Wayne. Some call the circuit the "re-gen" circuit or "braking"
circuit and they involve one or more power resistors. Most common problems
are these resistors or the wiring to/from them. I've even seen a fuse in
this circuit, that would be lucky.
Bart

[Tero Kaarlela]

Well there is no external brake resistor in the system. Only resistor that
would fit to be braking resistor is inside servo amp. It says 0.5 ohms and
measured that its ok. And no one has tampered with parameters. This
behaviour started few months ago and has gone worse since.


Tero Kaarlela
Eka-Sorvaus Oy

Post by Bart

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

I agree with Wayne. Some call the circuit the "re-gen" circuit or "braking"
circuit and they involve one or more power resistors. Most common problems
are these resistors or the wiring to/from them. I've even seen a fuse in
this circuit, that would be lucky.
Bart

[Wayne Weedon]

Post by Tero Kaarlela
Well there is no external brake resistor in the system. Only resistor that
would fit to be braking resistor is inside servo amp. It says 0.5 ohms and
measured that its ok. And no one has tampered with parameters. This
behaviour started few months ago and has gone worse since.

Take another look just in case, they are normally very large wirewound
resistors in a cage or enclosure often with fan cooling.

Does it still trip from very low speed?

try m03 s200 then m05.

If it still trips, I'd reckon that spindle drive has a fault which
probably only a proper service will deal with. Not sure how they sense
the current on the DC bus.


Wayne....

[Tero Kaarlela]

There is only one external resistor pack in machine and it has been
connected to Z-axis amplifier not to Spindle. It wont trip with s200 >
0. But it trips if I drop ie. from 5000 to 200. Or 5000 to zero. And it
doesn't occur right after command issued but after abt. 2 seconds.



Tero Kaarlela

Post by Wayne Weedon

Post by Tero Kaarlela
Well there is no external brake resistor in the system. Only resistor that
would fit to be braking resistor is inside servo amp. It says 0.5 ohms and
measured that its ok. And no one has tampered with parameters. This
behaviour started few months ago and has gone worse since.

Take another look just in case, they are normally very large wirewound
resistors in a cage or enclosure often with fan cooling.
Does it still trip from very low speed?
try m03 s200 then m05.
If it still trips, I'd reckon that spindle drive has a fault which
probably only a proper service will deal with. Not sure how they sense
the current on the DC bus.
Wayne....

[Wayne Weedon]

Post by Tero Kaarlela
There is only one external resistor pack in machine and it has been
connected to Z-axis amplifier not to Spindle. It wont trip with s200 >
0. But it trips if I drop ie. from 5000 to 200. Or 5000 to zero. And it
doesn't occur right after command issued but after abt. 2 seconds.

Well hopefully someone with more fanuc specific experience will chime in.

There must be something in there to absorb all that energy on decel.

Wayne....

[Cliff]

Post by Bart
the "re-gen" circuit

How many machine tools actually dump power back into the grid?
Should be a cost savings for some operations.

[Bart]

Post by Cliff

Post by Bart
the "re-gen" circuit

How many machine tools actually dump power back into the grid?
Should be a cost savings for some operations.
--
Cliff

A tech guy explained it as: Once the spindle amp stops driving the motor,
the free-spinning motor generates current and the "re-gen" alters the phase
of this generated current and sends it back to the motor to reverse its
direction, "braking" the motor. None of the current actually makes it back
to the grid. Its true, this braking power is "free".
Reading my literature, not all AC spindle drives employ external power
resistors, its an add-on for more aggressive applications. Trouleshooting
includes checking the "re-gen" power transistor (Q1) and what triggers the
fault include part of the thermal protection of the drive, which can even
occur after the motor is stopped due to a thermal transfer time constant.

[unknown]

On Tue, 29 May 2007 15:59:03 GMT, Tero Kaarlela

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

The transistor module is defective (igbt's) or the driver section..

Turn the power off and remover the driver connection.....plug

If any measurement between the base,emitter or collector is less than
a few hundred ohms it's a problem.

I have a proccedure for checking the module if you would like it.

The problem may be in the driver sextion as well. I have the
procedure for this check . This involves measuring the resistance on
connectors CN4 and CN5.

Good Luck


Daveb

[Tero Kaarlela]

Procedure for checking IGBT's and driver board would be really great.
Unit model is A06B-6059-H208#H583. If its PDF or jpg etc. Could you pls
send to my email: turo.kaarlela(at)co.inet.fi


Tero Kaarlela

Post by unknown
On Tue, 29 May 2007 15:59:03 GMT, Tero Kaarlela

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

The transistor module is defective (igbt's) or the driver section..
Turn the power off and remover the driver connection.....plug
If any measurement between the base,emitter or collector is less than
a few hundred ohms it's a problem.
I have a proccedure for checking the module if you would like it.
The problem may be in the driver sextion as well. I have the
procedure for this check . This involves measuring the resistance on
connectors CN4 and CN5.
Good Luck
Daveb

[unknown]

On Tue, 29 May 2007 15:59:03 GMT, Tero Kaarlela

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

The model number for those drives are like 6S thru 22S so if you give
me the # of the unit (A06B-6062-H218#500) or what ever I can come up
with proper print.
Daveb

[cncfixxer1]

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

This may have nothing to do with your problem, but could be worth looking
into. On my machine, on top of the cabinet in back, is a large ballast
resistor. It's about the size of a small loaf of bread. I had some strange
things happening with spindle shutdown, and got alarms, though I can't
recall which ones. It turned out to be this ballast resistor. I called Fanuc
on a Friday afternoon around 3:00 PST, the tech diagnosed the trouble,
confirmed when I checked it with a meter, and UPS showed up the next day
with a new one which was shipped from Chicago. Less than $200. It won't cost
anything to call Fanuc and talk to a service tech.
http://www.practicalmachinist.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topi
c;f=13;t=001549;p=0

[Matt Stawicki]

On Tue, 29 May 2007 15:59:03 GMT, Tero Kaarlela

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?

Perhaps the drive parameters need adjusting. What happens when you
command S1000 M3, then S0. Does the spindle stop? Or does it creep?
Then try S1000 M4, then S0. Does it creep? I don't remember which "F"
parameters control this, but I can check my notebook in the morning.

Matt

[Tero Kaarlela]

Well machine has worked very well for 13 years for us. This problem came
suddenly AND NO ONE has touched parameters. So I dont think it is
parameter related.


Tero Kaarlela

Post by unknown
On Tue, 29 May 2007 15:59:03 GMT, Tero Kaarlela

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?

Perhaps the drive parameters need adjusting. What happens when you
command S1000 M3, then S0. Does the spindle stop? Or does it creep?
Then try S1000 M4, then S0. Does it creep? I don't remember which "F"
parameters control this, but I can check my notebook in the morning.
Matt

[Matt Stawicki]

On Wed, 30 May 2007 10:15:41 GMT, Tero Kaarlela

Post by Tero Kaarlela
Well machine has worked very well for 13 years for us. This problem came
suddenly AND NO ONE has touched parameters. So I dont think it is
parameter related.
Tero Kaarlela

That's like not being able to understand why your car, after working
flawlessly for 100k miles, suddenly doesn't start one day. Gee....I
didn't do anything to it, why doesn't it start?

It can get out of adjustment all by itself. Otherwise, there'd be no
way to adjust it. And I'm not talking about machine parameters, I'm
talking about the drive parameters that can be accessed by the tiny
keypad (4 keys) that's on the drive itself. You don't necessarily have
to change them for it to be out of adjustment. Things wear, ya know?

You didn't answer my question. When you program S1000 M3, and then
program S0, does the spindle stop or does it creep?

Matt

Post by Tero Kaarlela

Post by unknown
On Tue, 29 May 2007 15:59:03 GMT, Tero Kaarlela

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?

Perhaps the drive parameters need adjusting. What happens when you
command S1000 M3, then S0. Does the spindle stop? Or does it creep?
Then try S1000 M4, then S0. Does it creep? I don't remember which "F"
parameters control this, but I can check my notebook in the morning.
Matt

[Tero Kaarlela]

Problem solved I replaced IGBT transistor modules and now machine has been
working correctly for few hours. Thx all for help.


Regards
Tero Kaarlela
Eka-Sorvaus Oy

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

[Bart]

Post by Tero Kaarlela
Hi,
Our VMC gives spindle alarm 1008 on display. Spindle units led display
shows AL-12(Excessive current on DC-link). Alarm comes when spindle stop
command is issued(M05). Spindle accelerates and runs fine but every M05
gives this alarm. Machine is Kitamura Mycenter 2X from 1995 with Fanuc
0MC. Anyone had this trouble here? If yes how it was solved?
Regards
Tero Kaarlela
Eka-Sorvaus Oy
Finland

AL-12
1. Output terminals or internal circuit of motor is shorted. Check
connections
2. Transistor module is defective. Check the transistor module
3. PCB is defective. Replace PCB