[zoeper]

Hi All,
I suspect my spindle drive problems are caused by a faulty power transistor module on the spindle drive.

Machine trips out OC when accelerated quickly in forward direction. Reverse runs fine though (99% of the time, but it has also tripped out before)

The power modules have the following specs and each package seems to contain duel darlington pairs:

EVL 31-055, 100A 550V ( 3 of)
EVM 31-050, 150A ( 3 of)

How can i test these with basic measuring eqpmnt (multimeter)
Can you still get replacements for these? and if not does anybody know of a suitable equivalent?

Drive is a Fuji Frenic V5000 Made in 1985

[JEFFY]

I don't think that is your problem, check and see if you your spindel control has a currant limit on on accell and try adjusting it up. I also just notice you listed the drive, I'll see if I have the specs and manuals for it.
Just for your info most times when a drive faults out like this it is either a control setting or a board failure (most likely a cap failure)
When trips out on OC is it the main breaker before the control or is it the control giving you the OC fault???
Hope this helps.

[JEFFY]

No luck on any manuals, but check this link to a past thread:http://www.cnczone.com/forums/archiv...p/t-17478.html
It may be of some help.

[zoeper]

Jeffy, I do have some manuals for the drive and i have taken the current pots to both extremes with no visible effect.
When it trips it is only the control that trips and the drive shows OC alarm

Pieter

[One of Many]

As you may already have questioned some components in this drive. Replacing only the packs is a gamble that could have you spending more money than finding another drive that is used, but functional with better technology and features than a 20 year old unit. To many other parts can go bad ofter the packs have been replaced to make it worth the time, effort and risk.

DC

[zoeper]

dc, Thanx for your thoughts.
My first choice would be to replace with new(er) drive, but i've had agents for new drives look at it and they just shook their heads saying their products can't do that. I don't know enough about the in's and out's of that drive to know how to set it up and replace it.
Budget for all this is very thin as i've uncovered some serious mech problems as well and this machine needs to start paying for itself really soon.

Do you know if you can readily replace the drive with another and what kind of drive do i need to interface with Fanuc 10t?

Would you know what $$ we're talking here?

[NC Cams]

My Fanuc drives are SCR drives that directly convert 3 phase AC to rectified DC.

I'd suspect yours are similar if not the same as these drives were used on 5T and 5M's with the model 0, 5 and up to the model 30 "Getty's-Fanuc) servo motors.

The drives take +/-10vdc signals and use it to sequentially fire SCR's to convert AC to bidirectional DC. They are sort of wierd in how they work - at least in comparison to today's DC PWM/ "H" bridge drives.

They do require tuning with an oscilloscope - you will NOT get one to work by turning pots and hoping to luck into a "fix". Moreover, there are some sophisticated ASIC's on the boards that go flakey which can cause them to fault out.

We located a guy in Texas who services the older Fanuc stuff and does so for a very reasonable price (we pay for our service and I have NO affiliation with him). Ask for Glenn at 972-465-3608.

It would NOT surprise me if contemporary servo amps would NOT fit between the control and the servos - Fanuc was NOT noted for using industry standard hardware. If/when you price service and or part$ from Fanuc, you'll readily $ee why....

[zoeper]

NC Cams,
Yes i gathered that about Fanuc! real nice guys ; )
The drive i am referring to is actually the spindle drive and the motor is a 15Kw Ac motor. Fuji does not support the drive in question any more, so if i cant have it fixed i would have to replace it completely. I would have to try and do it locally (South Africa) or the airfreight for the 50 odd Kg drive is gonna cost my other arm!

[NC Cams]

If Fanuc made the control and Fuji Electric made the drive, you can bet that Fanuc merely packaged it (the drive) and will mark-up any service work a BUNCH.

I'd beg borrow or steal any schematics I could get for the drive from Fuji and have any ciruits reverse engineered locally as much as possible. I've know engineers who did that on a contract basis here in the states. Not may guys can/will do it anymore as many electrical engineers aren't trained to do that sort of stuff anymore.

The trouble with darlington drives is that some darlingtons are REAL pricey and NOT available anymore. Or you have to buy 14 lifetimes worth of them to get 1 or 2. We ran into that problem with some massive stepper drives we bought into some time ago. WE got around it by installing mosfets and redoing the drive but it was simple DC which is far cry from an AC spindle drive.

Thankfully, my Fanuc lathes have SCR variable speed DC drives made with discreet IC's and not any ASIC"s to speak of. ANyway, I wish you well...

YOu still might give Glenn a call. Maybe he can give insight into where to get info/parts.

[zoeper]

Cams,
You dont happen to have an e-mail address for glenn?
thanx
P

[Al_The_Man]

I know with the Fanuc drives, I have replaced the all the darlingtons (expensive) only to have them blow again, Fanuc and its repair facilities always recommend replacing the driver board as well. as the original problem can often be there.
In N. America there is www.northamericanindustrial.com for repair/parts etc, they are Fanuc Authorized dist.
Al.

[One of Many]

These drives have dual encoder feedback. At least one speed and one marker pulse or magnetic prox. for spindle orientation. That does make it a challenge to replace it directly with another drive. Fuji could supply you with one for around $5000-$6000USD, YIKES!



Have you checked the actual current levels on each leg of the output to verify the current draws? If the control does not see the motor encoder on startup, from what I understand, the encoder on the back of the spindle motor is somehow tied into this type fault, which does not sound right, but eh, what do I know. If it were dirty internally or beginning to fail, this could bring up the same type of faults on accel/decel if the feedback is weak or drops out.

Typical of early drives with external feedback on dual inputs and finding a direct CHEAP replacement. I cannot believe in the last 20 years no one has retro'd one of these lathes to a newer drive at a far cheaper price.

DC

[zoeper]

Am i right in assuming that tech as it stands today, you should be able to get the same functionality with a standard vfd? I know this particular Fuji drive has got bothe analog and digital inputs. What i dont know is if it is from the controll side (speed command) or from the encoder(s) there is no encoder on the motor itself, but there is an encoder mounted on the spindle via timing belt.
I have contacted the agents for Fuji in the UK again to see if they can shed some more light.
At present this machine is slipping away at lightning speed. this is a purchase i could have done without!

[NC Cams]

Zoeper: Sorry no. I usually call their 800 toll free number.

Do a web search for Billor (perhaps Billore) Enterprises in Texas. They have a website.

[One of Many]

Well, I did forget that we were talking about a lathe. So, there would be no spindle orientation on this but it does have encoder feedback. On a standard VFD without feedback, they do not maintain speed as well under varying loads. The encoder may use its marker pulse to orient the spindle for threading, but that is seperate from the issues you are having. I'd expect that spindle marker/orientation would go back to the control direct to sync motion with the control not the spindle drive itself.

If you have a schematic, check all the terminals and then see what is out there in the market that has the same options. This could take some external support boards and devices to emulate what the current drive has built in.

The analog and digital inputs are not typically used together per say in terms of spindle RPM information from the control. It will be either one or the other as an option in the drive parameters. Same for feedback as in encoder or tach to track what is commanded verses what is actual.

At a minimum, I'd guestimate to have it sent out to a repair facility to be in the $1500USD range to have it repaired and warrantied. If you go with replacing the Tpacks without proof of their contributing to the condition, I have a sinking feeling you will be throwing money away with nothing to show for it. Some repairs on a shoe string buget are best left to those that can do it right the first time or replace it with a sure bet.

DC

[NC Cams]

Explanation of the $5-6K Fuji "service charge":

Unless the drive is relatively new, once an "old technology" drive is to the point of needing service, the Pacific Rim outfits often merely relace rather than fix them.

They "fix" your old one on an exchange basis - actually they take it back and charge you for a new one and keep the old one OFF the aftermarket to protect THEIR business interests.

I've seen many a case where a "whatever" supposedly can't be repaired. Yet, once you start to look into it at the schematic level, it can be pretty easy to start tracing signals.

Once you find a "should be" signal that isn't where it should be, it can be pretty easy to figure out where and why it didn't get there.

In this case, the current sense circuitry is either REPORTING too much current when it isn't drawing it OR the system is actually DRAWING too much current.

First thing I'd do is remove belt from motor to spindle and try running motor w/o load. A clamp on peak sensing current meter will be real handy (no mandatory) to have. You need to know if you ARE going OC.

If motor IS pulling to much current, fix motor. If not, delve into control. It is all a process of elimination unless you've BTDT and know what to do.

Again, if you can get schematics (beg, borry or steal) a person reasonably adept at electronic circuit tinkering should be able to figure it out.

Been there, done that and have done so successfully enough to keep money in my pocket instead of putting it in someone elses.

[zoeper]

Thanx guys, I have seen some very valid and sensible suggestions from you. I am going to get someone in to test the drive properly so that we can isolate the cause. The people at cmts in the UK does offer a repair service for these drives, but they can also supply the parts if needed. (these t-packs cost between 77 and 96 pounds each so poking at them is not an option.) I will keep you updated as to how it's going.

PS. Since everything is now stripped from the bed exept the headstock, is it safe to switch the machine on, and how can you test the spindle drive without zeroing the machine??? I would like to get the spindle drive sorted out while i'm busy on the mechanical side of things.