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Spindle Drive Problems

sneebot

Stainless
Joined
May 14, 2001
Location
Massachusetts
Machine is a Maho 600E2 (~1990). Been having what appears to be problems with the Indramat KDA spindle drive. All the drives in this machine are powered from a Indramat KDV which puts out 300V DC as well as 15V and 24V. All the axis drives run fine without issues. The KDA spindle drive does not seem to power up some of the time (more and more often). When it does power up it seems to drop out at times. I pulled the KDA drive and sent it to a test house and they indicated that it tested fine so I am completely baffled. The unit seems to be powered off the same supplies as the axis drives that have no problems at all. Measuring the incoming voltages to the KDA from the KDV all seems to be correct-- so I don't think it is a cable issue. Any suggestions on where to look next? On a related note the 432 control has a screen PLC-Mon that allows you to look at the binary interaction between different machine components. Does anyone have documentation on what the different positions (1-32 or so) correspond to? Position 22 flickers when the spindle is running- is this normal?
 
FWIW, years ago I owned a Maho e2, where it worked fine when I bought it but after sitting for 6 months in the shop without power, I finally connect it up and find out the Indramat spindle drive works, but is quite erratic and noisey. So I took it apart for a look see and found a few electrolytic "can" style capacitors looked suspect, so I checked them with my "still on the board checking" ESR meter and to my annoyance, they checked out fine.

But then I remembered the ESR meter is no good for checking dead short caps, so just for heck of it, try a regular ohm meter and damned if they aren't dead sorted (which you can only confirm for absolute sure by desoldering them and rechecking). So, that was the problem....new caps and it worked fine.

Your problem sounds slightly different and it is curious a tech firm found no problems with the drive, but just throwing out my little experience in case get really desperate and want to try other possiblities....I do vaguely recall it being quite a PITA to dissassemble the little bugger though.

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Also, dunno who your "test house" was, but I've found you can often only trust the folks that actually made the thing in the first place to do a proper test and repair. Don't know if you read or remember the long saga of problems I had with a spindle drive on a Cincinnati Milacron Sabre turning center years ago where I sent the drive off to be repaired, the shop declared it fixed, $1,200 later, get it back and still had the exact same problem !

After hours and hours of testing other components, I finally decide the problem HAS to still be in the spindle drive... so send it to the actual manufacturer, they fix it, it works perfectly ! (luckily I paid the first doofuses with an Amex card and was able to reverse the charges when they refused to even entertain any sort of refund even with absolute proof of their screwups)
 
Even before I sent it to the test house I replaced all of the electrolytic caps-- no change. It appears to me to point back to the spindle drive, I can't imagine what else could be causing the problem since all the other drives work fine off the same power supply. At this point it won't even power up most of the time-- no leds, no LCD display- nothing. I do recall your story and I cringe at spending more time and money screwing around with this.
 
Even before I sent it to the test house I replaced all of the electrolytic caps-- no change. It appears to me to point back to the spindle drive, I can't imagine what else could be causing the problem since all the other drives work fine off the same power supply. At this point it won't even power up most of the time-- no leds, no LCD display- nothing. I do recall your story and I cringe at spending more time and money screwing around with this.
Something erratic like that and getting worse sounds like contact issues of some sort. Are there any reseatable IC's in the drive ? Other than that the only "easy" fix (maybe) might be Stabilant on any wire connectors. Then you get into checking resistance at wires in cables from both ends. And then the real cringer...checking boards for deterioating wire traces or solder joints :willy_nilly:

Any of these Indramat drives ever turn up on eBay ? I bought an e2 vintage Indramat /Maho axis drive on eBay years ago real cheap, but I haven't paid any attention to them since.
 
Ribbon cable or it's connections

The drive may be loosing the +24 or 15VDC supply. Check the ribbon cable connection.

If you don't have a meter to check continuity try swapping the position of the spindle drive with one of the axis drives and see if the axis then has the intermittent.
 
Pipes--
You're suggesting the connection through the ribbon might be faulty? I've disconnected the ribbon from the KDA spindle drive and I all (four) 15V and (two) 24V supplies seem to be fine. The KDV has 16 pin connectors as does the KDA, but the rest of the drives have 12 pin-- so I cannot just switch cables. Looking at the literature online for the KDV the 12 and 16 pin connections use the same signals from the KDV just different design/ pin-out (They note both and how the signals are routed). I'd flip the cable around and try that as well but it (the cable) specifically notes that the black wire should always be on the bottom??

Don,
Never tried Stabilant on anything, I'd be willing to give it a try and will have to look into getting some. I've been keeping an eye out on ebay. The axis drives seem much more common (as one might expect). The spindle drive and power supply I have not seen come up (yet).
 
I was just using the PLC-mon screen to solve my I/O board problems for my oil pump. I don't know if your machine and mine use the same I/O boards, but your PLC-mon screen should show all inputs and outputs. For example, outputs 1-32 (board 1) and 1-32 (board 2) represents the outputs on the X2 connectors on the #1 and #2 I/O boards on my machine (a Maho MH1200C).

If your machine is like mine (which is very possible), I think what you are seeing is input X4.22 on I/O board 1, which comes from the Main Drive Load Indicator, an opto-isolated module that I believe shows the load on the main spindle. So, yes, input 22 (as well as inputs 20, 21, 23 and 24) would change due to running the spindle. But, I don't know what is normal. This appears to be a 5 bit A to D sensor.

Some info on the PLC-mon screen and I/O boards.... (You'll have to check your machine schematic to decipher things for sure.)

My machine has two I/O boards, 19A1.3 in slot 3 is I/O Board 1, and 19A1.2 in slot 2 is I/O Board 2. On both boards, connector X2, a 37 pin DB37, drives the board's outputs, and connectors X3 and X4 (DB25) are the inputs. The I/O number on the PLC mon screen matches the pin number on the connector. E.g. Output pin 22 is output 22 for that board on the PLC-mon screen. Pins 33-37 on the DB37 are not used. For inputs, I'm not sure how the numbering matches, but it is probably pretty obvious if you compare to the schematic, or look for an input you can monitor and see compare to your PLC-mon screen.

On my PLC-mon screen, the right half is I/O board 1, and the left half is I/O board 2. It's a very useful screen, but there's no documentation about this screen in my manuals. I had to figure all this out by comparing to my schematic, and checking real wires with a mulit-meter to see if their signal matched the PLC-mon screen. After a few comparisons, it all made sense.


As for why your KDA drive isn't working... What error codes are showing up on the 432 screen? If there isn't an error code, I don't know what to suggest, but these machines trace just about everything that can possibly fail. There should be an error code. Trace those errors, and you might find out it isn't the drive at all. The machine might be shutting down the drive due to an error condition somewhere else on the machine. That oscillating input 22 might be a clue. Maybe it's a failure with the spindle load sensor, and the KDA drive is being shut down because of it.
 
Well I'm glad this post re-appeared before I spent the time to try to recap/ summarize/ re-post.

Lohmeyer-- I'm getting an one error (can't remember the number) that indicates lubrication level low (in the auto lube). This is not the case-- topped off. The lube sensor receives its 24V signal (incoming) from the spindle drive, so when the drive is not powered it trips the error code. As soon as the drive (at random) decides to power up the error is cleared. I don't think the machine is shutting down the drive-- it appears that it's not powering up at all (the drive).

I will have to look at the PLC screen again after reading your summary.

Pipes-- I should clarify; I don't have probes small enough to fit into the connector. Instead I'm getting at the connector contacts through the side of the connector where there is an opening. There could still be a problem inside the connector with proper spring force, corrosion ect.
 
Pipes-- I should clarify; I don't have probes small enough to fit into the connector. Instead I'm getting at the connector contacts through the side of the connector where there is an opening. There could still be a problem inside the connector with proper spring force, corrosion ect.

The below is made by Pomona and comes in handy... they actually offer more sizes than what is shown here...plus black tips to help keep up with positive from negative.

6481.jpg
 
I cobbled together some test probes so that I could get into the connectors. The connectors appear fine without any weirdness at all. So it looks like the KDA should be receiving power from the KDV.

When I first power the machine up the KDA is dead and won't do anything at all. If the machine is on 1/2 hr or so it has a better chance of suddenly coming to life. If I shut the machine off and turn it back on the KDA will come right up (after it has been on).

There are 16 connetions in the ribbon cable between the KDA and KDV. Six (6) of these are supply voltages (15, -15 or 24V) not sure if the KDA needs some other signal on one of the other connections to initially power up. If not I would think the problem still lies in the KDA. What would only come up after prolonged application of power on voltage?
 
Ya, the lubrication low error being a result of the spindle not being on is a perfect example of what I was talking about. One error is often the result of something completely different. Sorry I can't offer any other suggestions.
 
Update:
To power up, the KDA only needs a +24V supply and return (Indramat labels it 0VL). Given the 24V supply the drive will actually tell you it is missing the 15V supply (on the LCD).

I enlisted the help of an electrical engineering friend (wizard) and he noted that there also had to be an internal power supply (in the KDA) as the LCD and other components were not running off 24V or 15V. Tore the unit down and powered up the main two PCBs separate from the power amplifier components/ PCBs. Observed some of the same intermittent behavior which pointed to a board mounted 5V power supply. Took this off and powered it on its own and observed same behavior. I haven't obtained a new one yet but this certainly appears to be the problem.
 
Maho, Indramat Spindle Drive, I01 alarm,No display on Spindle Drive,

I realize this is an old thread, however It has help me, along with some good advice from Sneenbot. So I'd like to add to it for others. Like Sneebot, after power-up we had no display on the spindle drive (the No-Power) was not "lit-up". This discrepancy kept the machine from coming up. I removed the board that was home to the FABRIMEX Switching Mode Regulator. We too had an intermittent condition, Inserted 24vdc to the Vin and it didn't fail in 30 hrs of testing.
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Sneebot:
Hi, i have been reading your past post about your maho cutting off and how you troubleshot it down to the "blue aux 5vdc power supply in the spindle drive" I read 2 of your post describing the cause and effect and how you troubleshot it. I too am having the same problem with one of my clients machines. I'm desoldering the unit to put on my bench and check myself. But from your description, It is the same thing, I'm having to wait on the thing to warm up. All other symptoms you described are rite in line with my problem.
I have an I01 alarm and it's due to the spindle drive not powering up.(I shorted out the BB circuit)
I'm quite certain my FABRIMEX Switching Mode Regulator is bad too.
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This was in fact the problem. I desoldered the "Blue Box" and ran 2 wires from the output solder pads to the outside of the Drive. We then connected a 5vdc power supply to the wires. We ran it this way for several weeks. I contacted Fabrimex, they are very slow to respond to emails, so we chose another option.
We purchased a unit from Digi-Key Mfg CUI INC. Part # PYB15-Q48-S5-T this unit is good for 3 amps vrs 1.5 on the Fabrimex. A few wires and some hot glue and we are back in operation. This has fixed the problem with the spindle drive. We positioned the LED on the unit to face forward so when the drive is installed we can look in the hole on the front and see the green light. I'm enclosing pictures. Thanks to everyone who contributed to this thread.
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Yep, that's the same part I replaced. My replacement lasted 6 months to a year before failing again. I was in the middle of a job and ended up buying a 5V wall wart from Radio Shack and running it off that for about a year before selling everything.
 
I just thought I should mention that another weak point in these drives are the small electrolytic capacitors around the small signal transformers on the driver board.

Milacron was kind enough to post about this problem in this forum, and that was what I needed to fix both mine and a friends drives.

I just thought I should mention that if you have your drives apart you should spend the little money and time it takes to replace these. They are most likely to fail from shorting at some point. So this will make your drives more reliable.

Anders
 
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Im having a spindle problem thats slightly different on my 90 maho MH600C with 432 control. I powered on today to charge the battery and went to run the spindle for a bit and noticed that the spindle didnt jog for the gearshift. The status lights on the front of the KDV and the LED on the KDA indicate no problems before trying to run the spindle, but after a moment of trying to start, the LED on the KDV faults and the KDA indicates FEEDBACK.
 
I pulled the drive and see one problem. On the second level board I have a bulged inductron pulse transformer. Maybe due to bad caps next to it? I dont see any reference to these on line other than Milacron was looking for one for a maho he owned at one point on some other forum. Maybe just the caps are bad? As noted above, the drive will power up, but when the spnidle is commanded to move, will error out with a "feedback" error and shut the drives down. I see that there are several inductrons in a spare indramat servo amp I have but not the same part number.
 

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Anyone know how to interpret the text on top of these pulse transformer? I believe that the Inductron zkb 409/098 R T4 transformer is the same as a VAC zkb 409/098 -54-120. The spare Indramat TDM drive I have has both VAC zkb 409/083 -53-120 and VAC zkb 409/082 -53-250. Ive emailed both VAC and Inductron but no response yet.
 
I remember from when I fixed my drive the previous owner had concluded that it was the pulse transformer. I'm not sure if that is really the case as they were already removed. But I was told that they had gone through considerable work to try to replace them, and ended up having to buy custom made transformers. I don't remember anymore what the cost of these were, but it was ridiculously high. Not something I would have done. But they came with the drive, and after replacing the capacitors and soldering in the inductors it worked as expected.

And remember, these capacitors fails randomly, and might cause different symptoms. They are always the first suspect, and if the drive is pulled appart you are foolish not to replace them. They will fail! And when they do they will most likely take other components with it.

The pulse transformers might very well be one of the components damaged as a consequence.

Although they could look bad from being heated up, but still not fail. Although most likely they are gone...... The best thing would be to compare them to the others. There are 6 paralell circuits to compare with, so this makes it easy to check for errors. In general transformers don't degrade over time in the same way electrolytic capacitors. After all there are no instable chemicals to degrade in a transformer (except for large oil cooled ones that is). But most definately there is in electrolytic capacitors! Which is why they fail over time.

Anders
 








 
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