VFS5 Drive problems - Switch to Vickers Vector drive?

Well my backup Arrow 1000 took a dump while waiting for the X motor to come back on the Arrow 1250C. The "Spindle Drive Not Responding" error came up with the Spindle Drive faulting out when commanded above 300 rpm from a stop. I can run it up to about 1100 rpm if I MDI it up in 100 rpm increments. I ohmed out the resolver and it comes back at 18, 18, and 30 ohms and no shorts between lines so I assume it is not the cable or the resolver.
So looking at the wiring diagram of the Vector drive off of the 1250 and the VFS5 drive off of the 100 it looks like they are nearly identical. The 1250 has the din plug on it for the controller to set parameters so if I program it from the controller to match the VFS5 will this work while I send the VFS5 out for repairs and wait for the 1250 X motor to come back?
Any thoughts?

hello the symptoms you describe would suggest the problem is with the power supply not the
spindle drive. i would recommend you test the psu before sending the spindle drive away.
regards
mallardfizz

Mallardfizz; Thanks for the reply and advice. I Checked the DC volts and did not see any dips or spikes but I will watch it as fault happens to double check. Fault light came on the VFS5 first before dropping out. I have loaded new components to "rated" load/output before only to have them fail. This is 15 years old and has had a hard life. With this being rated at 9kVA (37.5A@240VAC or 30A@300VDC) what would be a "safe" load to put across it? 15A? 20A?

I checked supply voltage as we stepped it up and it dropped to 275VDC at one point but had stabilized before it faulted at 1100rpm so I'm still leaning towards the drive and not the power supply. I will look closer at swapping to see if that is going to work. Also have a few other brands of drives around that I can look at to see if they might work. Getting desperate. If I can't get it going then we will be in a major bind next week.

I put in nearly 30 hours into this problem this weekend and last night. Got MotionLink Plus onto the drive and had the Err 14 Power Bus on the history. Pulled the 1250 spindle drive and it was nearly identical internally except for the logic board. I swapped the VFS5 boards into the Vector chassis to use the power side and no change. Tested the IGBTs with 12VDC and they are switching. All of the capacitors are good. Pulled the power supply and found one bad resistor on the top board near the fan but no difference. Checked the thrysitors but only for the diode. I recorded the AC lines in and never saw a drop. Ran the table from one corner to the other at full speed with no fault but I realize the spindle is the main load. Clamped onto the DC lines and can see 70A max at when motor commanded from 0 to 300rpm and about 5-8 amps running. I recorded DC bus voltage from the PS during the fault and I can see it dropping from 330 to 300 as I ramp up the motor before the fault but the literature says it can go down to 100VDC. Is this right? Is the load pulling the Power Supply down or is the Power Supply dropping out and if so why at 300VDC? I would try running with just the MotionLink but I'm afraid of losing the original tuning and since I can't see or record the locked up parameters I would then be double screwed. I would try putting the 1250 PS onto the 1000 but it has 15V logic out and the 1000 PS has 18V. ANY advise would be appreciated.

99.97% probability your problem is the PSR power supply. that is common fault in time.

You need only a simple test to prove it: use the MAX MIN setting on your digital voltmeter - you absolutely CANNOT see the fault with a regular meter.

Your bus is dropping to about 80vdc and drive is shutting down on undervolts.

what happens is when you change spindle speed you get a huge current load but if you MDI in 100rpm increments you can usually getto around 1000rpm before the steady current drw is high enough to droop to 80vdc due to fact the drive is a dc-dc converter; ie, power in equals power out; so as you increase output speed you insread output volts to motor so ask for more power. since bus is constant 325vdc until you get to full volts on the motor, the bus current drw is less than current going into the motor.

If you list the full part nos for both power supplies, we can tell you if you can swap them. Like previous question, our psr4/5 is identical to vickers since it is our pw anyway. they may have listed logic as +/-15v & 8v rather than more realistic (and our rating) +/-18 & 8.

btw, err14 power buss fault listing in history is normal

btw, err14 power buss fault listing in history is normal

Mike: Thanks for the reply and I believe that you an Mallardfizz are correct. I went through the post on the PM site and found a nearly identical issue. I will try and post a pic of the scope showing the voltage drop. The garbage line is the bus amps but lots of noise so … Attachment 228584 Anyway the Vector PS is similar but powered by 230V instead of the 110V that the PSR4/5 takes so it would take some re-wiring. Anyway I have a used PSR4/5 on its way and the 1250 motor should be back tomorrow or Tuesday. I learned a lot but frankly I would rather be making chips than doing this. Thanks again for the assistance and I will post results.

Mallardfizz, Mike, you were correct - Problem was the VFS5. Swapping it did the trick. Again the symptom was that the spindle would not go from 0 to anything over 300 unless it was slowly stepped up. The voltage would drop an then finally fault out. I did find out this is a 10K spindle motor although I'm too chicken to try anything over 5K. Now on to the 1250.
Thanks again

Yes - Typo. PSR4/5 NOT the VFS5

Hi guys this seems to be a very common fault where the PSR stops the spindle from increasing in rpm.
Does it indicate any particular part ie capacitors or thyristor fault. I'm thinking capacitors i have 2 PSR units that are broken and I am hoping to get one of them working.
One has a pretty damming fault where it arcs up across the main DC buss and the other has the above mentioned fault. The DC bus arc unit i have put to one side for now because its in a bit of a mess. I know that the fault is PSR because it came from a mill that also had the same problem.

any advise would be much appreciated

neither; drive circuitry for the input scrs.

Quote:

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Originally Posted by mike_Kilroy

neither; drive circuitry for the input scrs.

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Hi mike thanks for the reply.
Are you saying it's the spindle drive?

no. there are no scrs in the vfs5. only the psr4/5. i meant is it NOT bus caps or scrs themselves.

From what I've encountered, if it was PSU then you should get alarm 39-35 and/or 39-37, sorry I don't have much input but fairly certain your psu is still in working order pmcg.

I think that that alarm is on Acramatic i'm on Heidenhain. I am pretty sure that this symptom of being able to increase the speed bit by bit is down to the PSR. I would really be interested in which part of the PSR causes this failure as there not very complicated.
My understanding is the IGBT in the PSR is only for regen or braking. The thyristors could be faulty maybe they are not turning hard on. The capacitor are there to reduce the ripple from the thyristors switching. What else could it be the controller board?
I have two different versions of the main board b and c. The difference is that the coil resistor is replaced with thermal resistors.

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Originally Posted by petesurrey

1) not very complicated.
2)The thyristors could be faulty (mk comment: NOT) maybe they are not turning hard on.

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1) YES the SCR turn on circuitry is VERY complicated! Need it be THAT complicated for a soft start circuit? Maybe not, but the facts are the facts. If you understand electronic circuits in minute detail, have enough time to study it, and figure it out (40 hours? 80 hours?) and can do so without putting a dollar value on your time, you can fix it.
2) BINGO. I wish Exedy could be right to simplify your fix, but, alas, he is not.

Thanks Mike I can understand the frustration sorry I didnt mean to oversimplify. The truth of that matter is with a circuit schematic I might have a chance but without one it is as you say 40-80 hrs of studying.

let me add some so folks can understand why this happens....

an induction motor has need for TWO currents, 90 electrical degrees apart. The one IN PHASE with your AC voltage power source input, is called Isq and is responsible for making TORQUE. the one 90 degrees OUT of phase is called Isd, and is responsible for making a MAGNETIC FIELD inside the motor - to make it a motor. A PM motor has magnets to do this so has no need for Isd.

So on YOUR machine, Isd=18amps. Any speed, and torque, it is always 18amps upto base speed rating. It is 90 electrical degrees away from in phase, so you do NOT pay your power company for it - you only pay them for the Isq in phase current.

The vfs5 STILL has to supply it, so it still "counts." run at 100rpm, you will need about .1amp Isq, plus this constant 18amps Isd; put a clamp on ammeter around a motor lead, and you will see about 18 amps.

90 degrees out of phase.... the vector sum of these 2 currents is (Isq^2+Isd^2)^.5 - do the math and you will see your clamp on showing about 18amps.

Cool thing is this 18amps, being FAKE, 90 degrees out of phase, will be supplied by the capacitors in your power supply for free for you - it wont even show up on your 230v ac 3ph input lines to your psr4/5! Only the 1 amp in phase will show up. but even THAT wont show up at directly on your psr4/5 input power leads with the clamp meter!

the whole psr4/5 and vfs5, like ALL PWM drive systems, will pull power from your power company = power out/efficiency.... so assuming 100% for simplicity, (it is around 95%).

Recall how cheap vfd drives work: volts/hz constant curve.... these vector drives do the same basic thing. So if you have a 1500rpm base speed (where you hit 230vac into it), running 150rpm only has 23 volts into it. So put that 1amp Isq torque producing current into it, at 23v, and the current at the PSR4/5 input IS ONLY 0.1 AMPS AT 230V! Piece of cake to run!

Now start increasing your speed.... you can do the math in between, I will just jump to base speed - 1500rpm.... Now we are outputting 1amp at 230v, so the psr4/5 will be pulling the full 1 amp input! That is 10x higher current than the 150rpm's 0.1amp.....

Now, lets go above the 1500rpm base speed.... go to 3000rpm.... it is now constant HP range, we are putting out ALL the voltage we have, 230v, cant go higher, so what happens? WE CANT DO IT! Only way is for us to REDUCE the Isd magnetizing current - the 18 amps has to come down! less magnetic field means field weakening, means to we have to drop to 9amps for double the speed. THAT means the motor Kt is cut in half! Kt=#-ft/amp torque producing Isq. So we only now make 1/2 the torque per amp! So what happens to the amps into the motor? GOTTA DOUBLE! Now, we are putting out 230v AND 2AMPS! So input power is now 2 amps.

Do it again to 6000rpm: Kt has to drop again in half, so current doubles AGAIN to 4amps! Straight through from 230v AC input to PSR4/5....

So see? In summary:

150rpm pulls 0.1 amp from your 230v input to PSR4/5
1500rpm pulls 1 amp
3000rpm pulls 2 amp
6000rpm puls 4 amps
120000rpm pulls 8 amps

Now back to the PSR4/5 input.... Rather than diodes, it uses SCRs so it can softstart. The gate of the SCR must be ramped up to turn the SCR FULL on.

When full on, it acts like a simple diode. When not full on, it is whimpy! It only lets a few amps thru - if that!

So you can see why an SCR input power supply for a VFD will sag and cause you NOT to be able to get to higher speeds.

Now add it MORE amps for TORQUE to ACCELERATE to those higher speeds! Induction motors have a LOT of inertia; At the couple second accel ramps we programmed into the VFS5's for your machine, T=Jw/t - go look it up if you want more details - you will find trying to go up in speed by say 1000rpm will pull like 40 amps! NO WAY on whimpy not turned on SCRs. The bus droops, the drive faults. That is why if you try to go up in speed SLOW like 100rpm at a time, it will make it - until you get to the higher rpms anyway per above Kt reduction chart.

There is my 2 cents.

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Originally Posted by petesurrey

Thanks Mike I can understand the frustration sorry I didnt mean to oversimplify. The truth of that matter is with a circuit schematic I might have a chance but without one it is as you say 40-80 hrs of studying.

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Exactly! Well put. Unfortunately some companies stance on releasing schematics is strictly verboten.