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Lathe still down!

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Titanium
Joined
Aug 22, 2011
Location
Oregon coast
I asked in an earlier thread for advice about a power surge that
damaged my largest CNC lathe, a Takisawa TW-30 . The circumstance
again, as far as I can recall;

My employee was loading a fresh part into the collet of the
waiting lathe when the power crashed off, then went back on within
a fraction of a second. Moments later the main breaker of the shop
opened. (When I asked the power company what had happened they said
a farmer misdirected a manure irrigation spray nozzle which hit a
high tension line and knocked out power for a large area.)

When we were sure the power was back on he tried to restart the
lathe, but it would not run the motor for more than 5 or 6 seconds
before tripping the main breaker again with a "BANG!".

My normal technician was on vacation so we called FANUC, who sent
a technician out from Portland, which is 75 miles away.
The FANUC man went through a lengthy procedure, exchanging compon-
ents and trying different tests. He finally said he thought the motor
had been damaged, and/or the power from the motor controller to the
motor had been damaged, but that he was not allowed to change that
wiring because Takisawa installed it, not FANUC.

About this time my technician called, back from vacation, and soon
was here looking it over. He also read the FANUC tech's report, so he
changed out the wiring to the motor. No joy.

He tried changing the drive parameters back to what they were before
the FANUC tech changed them, as this machine has two sets of motor
parameters that differ after a problem in 2002.

Next he wondered if the slightly smaller wires he had installed may
have had a negative effect so he installed larger wires. I do not know
whether or not the wire he installed was the same as the original
metric wire Takisawa used, or indeed whether it makes much difference.

The wire change #1 didn't help so my Tech pulled the motor and sent
it to TIE FAUNC World for repair or replacement, we got the motor back
"As good as the original was when new" we were told.

Soon the motor was back and still won't run, the screen shows
"Spindle error 12" or close to that, "Spindle code 12"?

So he then changed the parameters again to a new set suggested by the
FANUC technician, again no joy.

Then he posited the question of whether or not the conduit running under the concrete had been compromised, so he went to Portland and
got a flex cable to bypass the wire in the conduit and all the way back to the main box. Nothing!

It's been months now and we are getting farther and farther behind, everyone involved wants this to be settled and I'm running out of ideas.

Please, if anyone has any ideas let us know, and I thank you all for reading this long post.
parts
 
did you check the breaker? I had a machine that would do strange things. Power it on and pop there goes the e/r module, powers sections ect. Finally asked the electrician to come out and pulled the breaker and one leg was fried. Still showed good voltages but after he pulled it out he was able to find the damage.
 
Actually the first thing the Takisawa technician did was replace the machine's breaker, the main breaker for the shop should be good as all the other 3 phase machines are running good.
 
What do you want to satisfy your title needs? "Lathe still down" implies a recent thread and it's a CNC lathe and it's still down. Maybe YOU should be locked.

diggerdoug, don't I recall a recent thread started by the owner of the site which you said should be locked? :D
 
It was sent to them because the motor megged low, the question was whether or not there was damage to the windings, which needed the attention of those familiar with Fanuc motors. There was, of course, much discussion back and forth before that, as there is now.

At this point, after months, you can bet there are questions being asked, and you could have assumed they were before. But please, if you don't have anything helpful to say,,well, because that's what I asked for.
The reason it's a relief now is because they were talking with my tech hired guns, and they have, I'm afraid, given up until they learn from higher scources. Now though it's a relief that they are talking to me that doesn't mean I understand what they are talking about, if it were a simple or easy fix it would be done already.
 
There's an artical in the Owners and Managers forum that you may want to read.


--------------

Think Snow Eh!
Ox
 
OX, we are a very small shop and I admit to having a bad history when messing with electronics, so I need help when machines break down electronically or due to electrical faults.
 
90% of the time I have seen alarm 12 on a Fanuc spindle drive it is a shorted transistor module. Since your machine was subjected to a power surge there is a good chance that other components damaged too. When a transistor modules shorts it can damage the board. Likewise, a damaged board can cause a transistor module to short.

Without knowing what all the Fanuc tech checked or changed it is tough to know where to start giving advice. I'll say this, shipping the motor off for testing was a total waste of time and money. After megger testing showed questionable results, a knowledgeable tech would just set up the motor to test run on line power. The Fanuc spindle motor is just a 3 phase motor. A very nice one for sure, but still just a 3 phase motor. With it running on line power, amp clamp each leg and check for balanced current draw. If each leg is pulling equal current (assuming your running on nice 3 phase power, not something like a rotary 3 phase converter) the motor is electrically OK. If it won't run, trips a breaker, or has substantial imbalance of current on the legs, then the motor is bad.

In the spindle drive, I'd look at the board, transistor module(s), DC bus capacitors, and, if equipped, current sense resistors.

Post up what drive this is. Pics at least. It may help narrow down some things to look at.
 
I had a similar thing happen to my older Takisawa TC-4. It stands quite a few days in the month and I had just got a nice order in for a few big parts.
Power surge, then after all was back I switched it on and started running a heavy roughing program and after about a minute the most annoying alarm buzzer I have ever heard (this thing is seriously loud and annoying but I guess that is the point) and the spindle just stopped.
Machine would poer up fine without issue but as soon as I wanted to change gear or turn the spindle on it would alarm out.
I phoned a Tech (this guy is seriously Fanuc Savvy) and he said that there was a good chance that it was either the spindle motor :bawling: or something on the spindle drive. He asked me to look at the spindle drive to see if there were any error numbers. I am embarrassed to say that I could not actually locate the drive properly. The X and Z I could see no problem but could not actually find the spindle drive as a whole, more about that later.

He came past and checked the motor exactly how Vanc described above and all was good there. He then said that he would take the drive with him to put on his test bench to see what was happening. He showed me what he was taking... the damn thing takes up nearly half the electrical cabinet and is a two man job to carry (this is on a Fanuc OT on the Takisawa). He phoned me a day later and said he had tested it overnight and found a few bad resistors, some dry solder on some of the points and some blown capacitors. He replaced them all and ran it under load overnight. He brought it back and said he tested it on a much smaller spindle motor than my Takisawa (this thing is a beast) and all was good but he wanted to put it back and see it running. Thankfully all went well and that was about 5 months ago, still running fine.

He charged me R11 000 for the repair (you guys can convert that if you want to) which was maybe a bit steep but he didn't waste my money or time by fiddling around in places that were not needed. He said that if that was not the issue he might have had to dig deeper but he would not have charged me for the testing of the drive just the call out and labor for removing it. Morale of the story is find someone that already sounds like they know where to start looking, not someone who is just going to guess.
See if you can locate someone who has test benches to test your spindle drive and just cough up the cash for it, it might be well worth it.
 
Lol part swapping techs should have there arms cut off.

A loss of power - surge won't normally do much to any motor. It absolutely will damage drive components. sudden loss and regain of power is a really good killer of drives.

Sure, by all means megga the motor, (better yet remove the wires at the drive and mega both wires + motor in the same hit) but understand being a little low whilst not ideal if the rest of it checks out then its really unlikely to cause a breaker to trip, especially when hung on pretty much any drive. Normally the drive protection would kick in way before the breaker can even begin to trip. Now a lot low is a whole different ball game and will cause issues, but so long as your merging well over line voltage to the motor you need to understand you have a fair bit of head room before anything will remotely arc over.

That said that's all largely irrelevant. If the machine is tripping the breaker on power on, then you fundamentally know its not the motor or drive output, because on power up the motor remains stationary on any lathe i have ever encountered? Hence if its truly tripping on application of power and is not immediately called to turn the motor - IE its sending no power to the motor at this point is it not logical to realize the fault must be in the drive or further back in the machine? After all a faulty motor - its wiring can not draw over current till its actually given a run command from the control and operates its output's sending power on said wires to said motor?

So far what you and your techs have done is trying to stop a flood by replacing upstairs dripping tap with out even turning the water on simply because every time you turn the water on it floods out the front door and you know the upstairs taps old and potentially slightly drippy but you have no real fucking clue were the leak is. Sure you know the leak is in the house, but your collectively clueless as to were. Slightly low on a megga is at worse a dripping tap, if the person with the megga has a clue its primary school multiplication to work out the size of that dripping tap. Your looking for a flood not a dripping tap. Now sure a low enough megga reading and it can arc over, but again, the whole idea of megging something is your measuring it at above operating voltage hence you know its not going to arc over at line voltage.

Good techs examine and chase a fault using measurements, a machine is a logical process of events some mechanical some electrical, a fault has symptoms take measurements find the fault and repair - diagnose it. Its that simple.

Shit techs guess and play part swap-er roulette. Whilst there customers suffer from ever more down time. Thats the core of your current issue. As to multiple techs that only are responsible for there part of the system, yeah i wish you even better luck with that, because that just becomes a constant his fault - her fault issue, especially on a intermittent fault.
 
Textbook example of incompetent techs, but others ITT have already made that pretty clear I think.

Just to add in case you face this kind of problem again (with other techs): Changing parameters after an event is a massive red flag.

When you are paying outside people to come in and fix your stuff, don't tolerate anyone who isn't getting the job done. There are very few faults that can happen on a cnc that a competent tech can't identify with confidence on their first visit, and repair on their second.
 
Although I thank all for responses and new directions I want to make sure to not besmirch the character of the people kind enough to try to help, I'm a desperate man here and desperation is a dinner not enjoyed in solitude. The people involved all have good reputations, 'nuff said.
I can't post the service reports or images because it was sent as "confidential" and, for the reasons above, I don't want to pick at anyone's sensitive reputations.

Today a technician from a well known FANUC repair center (Independant of FANUC) is expected to call my local tech, who doesn't give up but had reached the end of his allowable time chasing leads. I was just told that he's here again, so perhaps he took the call. Again, though this has gone on for some time the original local guy was on vacation for most of that time.
I will post any causes they find when the machine is running again.
Thanks all,
parts
 
Here it is half way through February and it's still broke down, tens of thousands of dollars spent and components rebuilt and still it won't work right. I suspect my tech of 20+ years has turned away from it, don't know as he's not answering my emails.
He had it running, said as he ramped RPM's up and down he's getting that "Spindle Alarm 12" with a shut down.
Since he didn't talk with us when he left I sent an email asking if it was ready, to which he responded not yet. Two short sentences. I'm leery of calling him but will have to break down and risk it so I can know what to do next. Maybe he's just attending other customers? I've asked twice in emails what's next and am not getting an answer.
 
At this point, after months, you can bet there are questions being asked, and you could have assumed they were before. But please, if you don't have anything helpful to say,,well, because that's what I asked for.


Not that I am a tech, nor should I feel compelled to help after you being bitchy, but:


When we were sure the power was back on he tried to restart the
lathe, but it would not run the motor for more than 5 or 6 seconds
before tripping the main breaker again with a "BANG!".

Did it make this "bang" once, or can you repeat it?

"Bang" from my experience is when the output drivers (kan't think real name - and there may be diff types at that) go out of the drive, but that's only once.

Have you been inside the drive yet?

These are likely clear to the bottom of the unit, mounted on the back plane - cooling fins.


You may need to qualify them with a meter, but the one(s) that went bang shouldn't need no stinkin' meter to qualify.

Does it make the same alarm with the motor leads hooked up or not?


Wouldn't think that it would ever start to spin the motor with a bad output driver tho.


???



s-l500.jpg



--------------------------

Think Snow Eh!
Ox
 
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Jeez. At this point you could have bought a whole new spindle drive.

I wonder if this is a regenerative drive. Bad IGBT module is pulling too many amps. Does anyone in Oregon own an amp clamp?

At this point you've changed about every other component: main breaker, motor wiring, motor rebuilt, etc. The drive is about the only thing left.
 








 
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