[pmcg]

First off thanks in advance for any response to this problem. I think I know the answer but wanted to run this through what really is the best forum on this machine on the net.
This is an Arrow 1250C with the scale option. The problem started about 2 years ago when the X axis would fault when driven rapid. Now I can not remember if it was Foldback or P (over current). Sent drive and motor out and had them tested and came back "good" but was still giving us problems.
In any case we configured it to run at 50% and limped along for a while until last week when the Y and Z would creep when they were powered up. X did not move but faulted with a P on the drive after about 10 seconds.
I've tested the power and encoder cables for continuity and insulation problems and they all appear good. X screw is free and moves easily. Motor ohms out at 3.6-3.7 ohms between poles. Supply voltage is good (315V at idle).
Removed the motor power cable at drive; no fault
Motor power cable connected to drive an disconnected from motor: no fault
Power cable on motor and drive; faults with "P".
This is where it sits now but I seem to remember during this cluster seeing the Z drive with the over current P fault on the drive display but that may be my memory playing tricks.
Drive is the Vickers AS10300 and has been gone through in 2009. Motor is the Vickers FAS MT504A9-F9A3-071 and was rebuilt also in 2009.
Anything I am missing?
Problem appears to be external (motor) but I have no real confidence in this diagnosis.
Switching the X drive to Y axis motor is my next step but if I remember correctly I've been led down the wrong path before trying this trick.
What should I see on the power leads to the X motor at idle with an inductive clamp ammeter? What voltage?
Thanks again.

[slowlearner]

There are a couple guys on this forum that are real good with these controls and drives. You should hear from one of these good people very soon.

[mike_Kilroy]

if indeed P on multiple drives then it could be noise.

back to basics for a sec: our P fault is generated in the output SMART IGBT module (IPM) and we simply display it as a P. It USUALLY means an output short - in cable or motor. This fault is activated by output current CHANGING TOO FAST; way faster than a controlled accel or decel can do - ie., if current changes in some number of microseconds, the P is generated. Only way that normally happens is by a short.

high capacitance on outputs also can cause this.

we found on an 18 axis system that we could not prevent random, and sometimes solid on a particular drive location, P faults. we deduced this was from all the PWM switching noise from all those drives; this noise goes thru dc bus to ac input lines too, and with so many drives in parallel on one 3 ph power source the noise just confused the IPMs and at the end of the day our only solution was to reduce the no of drives.

So it is pretty important to know if the P is only on x or not. If just 1 axis then it is still likely a short in the cable or motor.

It all worked you say in 2009 - 5 years ago. It seems like you are saying it has gotten worse and worse as time went on now..... Might your motor have cutting oil in it? Dirty oil provides paths for shorts.

NOt sure why running at 50% speed stopped (reduced?) the P faults.... Unless dynamic friction was significantly higher at 100% speed than 50%, the motor current would be identical so there should have been no difference.

We have helped folks find P issues in past where they swore the cable was ok, only to find a small chip in it under the table, or a frayed solder connection at the motor connector side of the cable that they did not see. tough to find sometimes.

If you sent the motor and or drive to someone like us to check out, unless the motor fails megger testing (we, and maybe some others, use a fancy computer system that does 100 times more than megger tst alone), we probably would not duplicate the problem either, even with bench running the motor/drive running back and forth for hours like we would do.

Luckiy your issue is x not z so you CAN swap x & y. Altho you dont want to do this, it prob is the right next path to take.

PS: you asked what to see on motor leads for amps and volts: absolutely nothing of any value.

[pmcg]

Mike; Thanks for the response. Motor is out to be tested. Cable was checked using Fluke Insulation meter set at 250V. I was thinking if I knew the amperage out of the drive I could see if it it was a short to ground or a short between poles but not really that important. I'm creating a log of all of the problems we have had with this machine (symptom, action, result) and once that is done I might have a better picture of this problem. I will post once I have that done. I can say that it is lengthy and includes a similar issue on the Y axis that was fixed with a replacement drive but there may have been more to it.
The X has the AS10300 and the Y uses the AS10301. I think these can be switched temporarily to test the motor. Is that right? Thanks

[mike_Kilroy]

I had a case last year where our customers maint tech meggered with their fluke meter on one of these drives and insisted the cable was good: Imad him VERY mad when I told him it was not and had an intermittent short. He wouldn't talk to me anymore so I had to work with his boss. I made the boss take LOTS of panels of this formica making machine and guess what? We found the cable had been rubbing up against another motor pulley 30 feet from the motor it was running, hid behind the panel and was rubbed thru and had exposed motor leads and shield. It was INTERMITTENT so his megger test meant nothing. Tech made up and bought me a coke afterwards. Moral of the story is you really need to take the shells off the connectors at both ends and stick your eyballs in and look and also check whole length for a small metal chip stuck in it (or needle if you pissed off the operator and he wanted time off the machine ).



yes you can swap temporarily for test. But IIRC wthout looking it up I believe we supplied as10300's for both x&y and as10301 for Z - maybe someone swapped your drives around over the years? or the 301 on y is a replacement someone got once? or I could be wrong w/o looking up arror 1000 for sure. the motors the same for x & y aren't they? (sorry if my memory is not so good)

[pmcg]

OK: Finally getting somewhere on this one; Motor tested good static but got very hot after about 1 minute of running; bearings or clearance issue. Waiting for its return to test on the drive (off of the machine). Pretty sure the 10300 was stock on X and 10301 was on the Y. I'm the second owner (1st owner had it for about a year and kept very good records with no major services). This is the 1250. I do have a spare 10301 drive that is supposed to be good. I might try it in place of the questionable 10301. Will keep this update on progress.

[pmcg]

Ok; First of - Mike, you were right on a couple of things; Both X an Y were the 10300s and I should have swapped the drives to motors. Although the motor did need work it did not solve the problem. The original and the "spare" 10300 have same fault with either X or Y motor. So, since the Y axis was working previously I assume that both of my 10300s are dead ("P" error). The BDS Kollmorgan drives see a lot easier to repair/replace. Any chance I could go backwards and put one of those in? It looks like hours of wiring but better than days or weeks of down time.

[mike_Kilroy]

wow! never heard someone want to go from 3 generations old back to 5 generations old! Your experience on rprs on bds4's vs servostar does not mirror ours either - just the opposite for us

anyway, sure you could if you can find one; we still handle rprs on both for cincinnati and lots of other folks, and have lots of spare parts. we have not been able to keep any bds4 special cincinnati style comp boards in stock tho. We have about 1/2 the models NOS or repared in stock but not all. we sell them for $ 3000 everyday& as10's for less IIRC. BUT WE HAVE PUT LATEST NEXT GEN DRIVES IN PLACE OF BOTH - these drives are around $ 1200 and brand new, not semi worn out. If you want to go that way we can help with wiring mark up etc - email me if interested in that or a repair.

I would guess that the bds4 running in to a short will fault out and save itself 2 out of 5 times; as10 newer generation with faster short detection 4 out of 5 times, newest akd drive 49 out of 50 times. So you really got to find the short rather than retrying it or eventually the drive does pop output IGBTs.

BTW, when we have a really intermittent drive that shorts itself out, we sometimes put a little 3fuse 3AG fuse block in series with the motor leads to save the drive - and show us which phase is the troublemaker... anyway, since you still seem to have a potential cable short, doing this might not be a bad idea for you for too to help figure out what is shorting? Just an idea.

[rockservo]

Problem with Vicker AS series as well as regular Kollmorgen S series amplifiers is in input circuit of the drive. Their IGBT's are well protected, not like BDS4 drives. What Mike says in last post about adding a fuse block, that's great idea, at least starting point. Again, most likely your input circuit not power section, in some cases bad opto coupler or driver IR2110, less likely IGBT.

[mike_Kilroy]

Problem with Vicker AS series as well as regular Kollmorgen S series amplifiers is in input circuit of the drive. Their IGBT's are well protected, not like BDS4 drives. .....Again, most likely your input circuit not power section, in some cases bad opto coupler or driver IR2110, less likely IGBT.

Welcome to CNCzone Rockservo!

Just wondering what you might mean by this comment? Also, where is an opto coupler you mention & what is an IR2110?