Dear Nulizhang and others,

Recently we’ve bought a used Gildemeister NEF 320 lathe.

This lathe is powered/controlled by a Simodrive 611 with 2 LT modules (rebranded by Heidenhain)

One of these LT modules controls the main spindle motor, it has a lot of numbers on it:

SIMODRIVE LT-MODULE INT.50A (Heidenhain calls it DDC2)

1P 6SN1123-1AA00-0CA1

S TT-566018901015

VERSION A

This LT module has 2 large IGBT modules (EUPEC BSM50GX120DN2(6))

On both of these units the N terminal has burned away (see pictures)

My Questions are:

What might have caused this problem? Is it a common problem? Strangely, the machine was still operating perfectly, it was a pure coincidence that we discovered the burned PCB.

I can buy new IGBT units but these are expensive and to replace them is a lot of work.

On the other hand, replacement boards are readily available on the internet but there are differences in version numbers. The outside cover of the unit is marked VERSION A, the PCB itself has a name and number box that says: SIEMENS ABCDE with ABCD crossed out and E encircled (more or less) which seems to indicate a version E for the PCB, the number is 462018-7925.11

What do these version letters mean?

There is a complete unit available on the internet but this is a VERSION C (outside label)

Do I need to get the exact same version letters?

Is there a chance that the problem will reoccur once I have replaced the unit?

All in all my questions boil down to: what should I do to solve this problem?

Thanks a lot for your time and effort and I hope you can help us out.

Sincerely, Jaap.

Dear Nulizhang,

Thank you for your reply.

I'm sorry that I have not been totally clear about the situation on our side, I didn't know it was important, this is my first machine with a Simodrive.

My name is Jaap Leutscher. I have been repairing, maintaining, restoring and rebuilding all sorts of equipment, tools and machines for over 40 years and all over the world. I usually get called in because no one else is willing to tackle the problem. Sometimes this is because the machine is too old or even antique or there is no documentation available or the economic value is too low for an expensive repair, etc. Could be anything.

I have studied electronics in the 80's but most of my experience is with old school mechanical systems and relays.

But now that electronically controlled machines are getting older I increasingly find myself confronted with all sorts of dead PCB's and other malfunctioning electronic equipment.

With a mechanical system it is usually not so difficult to 'figure out' how it is supposed to have worked. With electronics you need to have the proper documentation. Therefore I'm turning to you with my questions.

The machine I'm working on was bought by Nelissen Decorbouw in Haarlem but turned out to be faulty. They called on me to try and repair it.

So, I'm NOT the end user, I'm the repair company. I hope this makes it possible for you to help me out. Sorry for the misunderstanding.

In the meantime I have bought a used central power PCB (the one with the IGBT modules on it) from a 50A module but this is a C version. It is almost identical but has different IGBT driver IC’s: SIE20031 vs IE20034 on the original board. These IC’s appear to be proprietary (Siemens?) units with no documentation available online. It is impossible for me to check if I can use this board or not.

I also have a question out of curiosity: The IGBT modules used on these boards ( BSM50GX120DN2(6) ) also seem to be proprietary (Siemens?) modules that are different from the standard IGBT’s I can find online. Instead of the usual 6 they seem to have only 3 IGBT’s with 2 modules together forming a 6 IGBT 3 phase bridge. Is that correct?

Wishing you a happy new year I hope to hear from you.

Sincerely, Jaap Leutscher.

Dear Nulizhang,

'Time is money' might be true for a company like Siemens but it is not a universal truth. small firms like the one I'm trying to repair this Gildemeister for tend to have less money but lots of time. They can buy a used machine and spend time to get it (back) to a running condition.

For want of a better advice I bought the second hand unit as mentioned earlier and installed it in the machine.

After everything was reassembled (including 2 new fans) we restarted the machine. That seemed to go well, manual control went well and a simple program was run correctly once but the second time it went wrong. The program ran well until the last line. Then the spindle stopped and then turned very slowly to the stop position as I believe it was supposed to do in this program. But when the stop position was reached the spindle stopped abruptly and with a huge BANG. It was as if there was a full DC on the motor for a short time or maybe the full voltage in antiphase, I don't know.

And after that: nothing. An error message did appear: (translated)

“Emergency stop     SW-IPO     4713, channel 1”

"no phase current in the motor conductors of axis S1"

“SPS     1208     F: Falt Emergency stop-circuit”

When I started on this machine I had a machine that worked flawlessly albeit with a badly damaged LT-Module. Now I have a machine that is almost dead with a main spindel that does not want to rotate at all.

I’m afraid I now have a broken DDC2 module as well.

Isn’t there anything you can give me to help me out?

Was I wrong to replace the E-version LT-module with a C-version?

Is there a way to test the workings of a DDC2 module?

I’m still hoping you are willing to help us.

Sincerely,

Jaap Leutscher