# Fischer Panda 55/4 55KW Mercedes Powered Troubleshooting Thread



## Greasysidedown (Aug 24, 2021)

Welcome and contribute to this thread since there (as far as I could find) is no other like it on the internet. This is my first post to this forum but I'm highly active on car forums to this day.

What we have is a circa 2002 Fischer Panda 55kw 3-phase 60Hz Asynchronous Generator with 314 hours. Mercedes turbo diesel OM364A. I got this from a neighbor who told me it was running one day and he forgot it was running. Came out in the evening and found it was "very hot" and wasn't making power. I put little credence in what he says however so take that with a huge lump of salt. I decided to take a whack at it and bought it for $2000. It was so clean and runs so smooth I figured I could probably make it work again. I'm an Aerospace Ground Equipment tech from 20 years ago (USAF) and we didn't have this style of generator to play with so this is new to me. It uses a huge bank of capacitors to excite the field.

I contacted Fischer Panda USA and they gave me the actual manual for this thing in German/English but it's VERY hard to understand what they want me to do. The guy at FP told me to "flash-in residual magnetism" and said "touch 24v to H1.1 backend leg". Then the other guy there chimed in with more lingo I'm not familiar with by sending me troubleshooting forms doing impedance and continuity measurements across "Z1.1" and "Z2" etc. More lingo I don't know what they mean. I asked for more information and they told me that's all they can do since they are only supposed to help the original end user AKA "military". So much for that avenue.

Email from today was this: "Your next task is to flash the backend to install residual magnetism. Take a 3 foot piece of 14awg wire and put a 10 amp inline fuse in it. Then, touch one end to the B+ starter post terminal and the other end to the H1.1 backend leg inside AC output box. If that doesn’t work, test the backend for shorts leg to leg and legs to case ground. Literature attached, remove all backend stator legs from ac box to isolate the backend from gen. Now, fasten together the windings as described in the first attachment. Finally, test all legs and record your data on the second attachment."

Then: "L1/2/3 is generator load out. You have 3 stator windings in that backend, I need you to isolate them from each other by tying the ends together. And when you test impedance between the windings and each winding to ground you want at least 1Mohm of impedance or the windings will not hold insulation between each other or case ground when producing. Finally, this was sold as a military unit and I am not really supposed to help anyone but original end user with this type of gen. You have experience and the literature for your model, I have done what I can do, good luck."

So at this point I want to flash residual magnetism but there is no procedure in the manual that makes sense (see attached). Anyone out there have experience with this type of thing? Am I to remove that big heavy plate endbell cover and tie stator wires together? I'm skeptical and cautious since its a tight fit back there with the giant radiator in the way and I don't want to do something I don't have to do!


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## iowagold (Jan 22, 2020)

nice looking gen.
seek out one of the power support guys from the military.
most of them should be retired by now from the 1980's to 1990's.
do you have the mfg year on the tags?

flash the gen is super easy to do.
if you know what you are doing.

head over to you tube and search that.


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## Greasysidedown (Aug 24, 2021)

I'll sit down tonight and do more digging. This is a winter project so I got lots of time to learn about it. 

I just now put the enclosure back together and its VERY quiet. Runs so good it makes me motivated to get it going.


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## iowagold (Jan 22, 2020)

take a look at section 3.3.4 in that manual
it looked easy to me.
basic they are connecting battery voltage for a couple of seconds to the output of the gen set.
and that will re flash the core.

most of the time they use a small fuse that will blow during the flash.
that helps keep the gen voltage when it does come to life out of the dc battery.

pretty basic stuff for a gen tech.
or an old school tube radio repair guy.


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## iowagold (Jan 22, 2020)

a good cap tester is where i would start...
you might have a bad bank of caps...
age kills them.
look for date codes for mfg on them.


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## Greasysidedown (Aug 24, 2021)

I tried flashing and nothing happened. I just now read the entire manual slowly and I'm suspect of the caps. The generator data plate says 2002 mfg date (in German of course, it says Bj. 2002. Baujahr.) I'll do some cap testing in the morning and definitely report back. This is pretty fun stuff.


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## Greasysidedown (Aug 24, 2021)

As far as flashing the field goes, here's what I've got so far. The generator has 3 pairs of cables coming out with each pair attached to L1/L2/L3. I disconnected the output lines leaving the "pairs" isolated. With generator off I then put 12VDC (+) to L1 and (-) to N. This is where I'm not 100% and need someone to clarify. By putting 12v through L1 this should short to N but it didn't pop my 10a inline fuse in doing so. Matter of fact nothing happened, no spark, no melting wires, nothing. My little Fluke shows 0.0 ohms between all terminals (L1-L2, L2-L3, L1-L3, L1/2/3-N). The manual says to measure mili-ohms but my meter won't go that far down.

Another thing I'm struggling with is the capacitor bank and excitation. This genset has 3 BIG cables coming from the capacitor bank that bolt directly to the generator leads at the AC output box. Am I understanding this correct that there is DC induced in the stator windings (from asynchronistic behavior) that overlays the AC output and it is this DC that charges and keeps the capacitors going? This generator has an AVR but I don't see that it influences voltage through excitation, rather it (possibly?) regulates engine speed. The manual states the AVR can be disabled and you can use the generator in standalone mode by adjusting the pump lever. All my questions would be answered if FP would have complied with my original introductory email requesting schematics. I'm a schematics whiz. I'd have gladly paid them too.

Too many words on this post, most of you will probably fall asleep reading. Meanwhile I'll be out there burning up caps and frying stator windings...

When all this fails I'll make a tractor out of the Mercedes engine.


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## Dutchy491 (Sep 18, 2019)

Way way over my head, but wish that I lived next to you so that I could come over to hear that engine purr...and watch with baited breath as you attempt to get it to produce power. Keep us in the loop, Dutchy


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## Greasysidedown (Aug 24, 2021)

5 bad caps. These are 100uF caps that have a mounting peg on the bottom.

I tested for residual magnetism by running the generator with the stator unhooked and voltage tests across L1/2/3 to N yielded zero voltage. It must need flashing but seems 12v isn't doing it. I'll keep at it.


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## iowagold (Jan 22, 2020)

i think some where it mentioned 24 volts..
check on that.
*yea get the dod part numbers off the caps and replace them all.*
and verify the new ones and write the numbers on the bottom of the caps with sharpi.

do you have a coil and choke meter?
you need one to check the windings for flash over.

also with every thing isolated use a good ohm meter to see if the windings are close together on ohms readings.
and check them to chassis ground as well for shorts.

did this unit have brushes???
if so check the slip rings and brushes..
and the brush holders.


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## Greasysidedown (Aug 24, 2021)

No brushes or slip rings on this big boy. This is an asynchronous self-exciting generator with capacitor banks attached to the L1/2/3 lines directly.

I ordered 5 replacement caps from digikey that are the same exact ones, $20/ea. I removed every single cap, did the Fluke capacitor test, then charged each one with a 12v battery to see if they would hold. All but 5 passed these tests.


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## Greasysidedown (Aug 24, 2021)

It works! That was much quicker than I expected. So I traced the individual wires from the capacitors and determined they are all ganged together (parallel) sooooo, I simply added 12VDC to one of the capacitors (melting the janky wires I made in the process) and it worked! I figured recharging the caps at least a little would flash the field. I verified it worked by shutting it down and restarting without 12VDC and it came up like it should. So now I have this giant 3-phase 55kw genset and no 3-phase equipment to run off of it. Oh well.

I noticed though since it's missing some caps the voltage came up over the course of about 3 seconds when I feel it should have leapt right up to 120v. New caps will be here when they be here.


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## iowagold (Jan 22, 2020)

ha!
glad you are on the road to a good back up gen on the cheap!
i would think on replacing all the caps now that it is working!
think of it as an update PM (planned maintenance)..
then you should be set for another 10 years of run...

did you see the high temp versions of the caps??
they are higher cost but they are a 15 to 20 year cap..
and work great under heavy loads...
that is an upgrade thing..
panasonic makes some of the best ones if you can get them....
we use them in BIG computer power supplies.
some are at better than 1% as well.
hand picked stuff.


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## Greasysidedown (Aug 24, 2021)

I found identical ones on digikey made by Kemet in Bulgaria. I get legit VW parts from Bulgaria so why not caps eh? They are 470v 100uF with a 5% tolerance. The generator makes power with 5 missing so it would appear the total capacitance isn't a critical factor on this thing. Its got 4800uF total!


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## iowagold (Jan 22, 2020)

just do not load it up heavy with out the caps.

yea a bit of govt over kill is a good thing!
nice on the 470 vac!

so one of the old caps was dead shorted?


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## Greasysidedown (Aug 24, 2021)

Got new caps on today and all is well. 4 of the old ones would't take a charge and the remaining one puked its guts out the top. Next stop is building a trailer for it. I have to go back east for a few months for work so this project is on hold for the time being.

Neighbor offered to bring his 10k forklift over AFTER I ruthlessly dragged it to the back yard. Sucker is heavy and my poor little Takeuchi didn't like it one bit.


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## iowagold (Jan 22, 2020)

yea make sure when you do a heavy duty axle trailer to do one with outriggers or 4 corner jacks so you can setup and level the trailer.
and yes a lawn tractor works well with a draw bar works for moving it around on the property after it is on a trailer.


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## Greasysidedown (Aug 24, 2021)

Quick text update. I have plans to build a trailer, electrical cabinet, and a big aluminum fuel tank for this thing.. in December. Currently I am in Toronto for another **** nuke job. I'm new on this forum but will not forget about it! I'm weeding through posts on VWVortex and noticed low-post number people tend to just disappear. Not me! I've got a few pieces of equipment that will need some future help I'm sure and dammit I can't do it all myself!


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## drmerdp (Apr 10, 2018)

Cool, glad it’s working out. I’m looking forward to a trailer build thread.


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## Greasysidedown (Aug 24, 2021)

Back home for a 2 month break from Canada. Generator won't stay running without the bypass switch pushed. I reeeeeealllly need a wiring diagram for this thing. I went through all the safety switches and relays to no avail. This thing uses a hodge-podge of off the shelf gear like the Saab fuel relays and the Kubota tractor timer relay for the IP shutoff. The manual says the thing should start when you flip the toggle to "on" and mash the soft button "on". But it won't operate the fuel pump or shut off solenoid without the bypass pressed. I emailed the Fischer people in Germany again. Bout to take the engine out and put it in a truck.


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## drmerdp (Apr 10, 2018)

I suppose tracing the wiring and tagging isn’t an easy task. A wiring diagram would be a game changer.

The high pressure pump should be gear driven right off the engine, is it a lift pump that is failing to turn on?


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## Greasysidedown (Aug 24, 2021)

You are correct. Tracing and tagging was a thought I had for just a brief moment. No way I am willing to disassemble and cut out all the wiring though. The generator acts as normal when the bypass button is depressed and will run forever as long as you press that button. The crap manual Fischer gave me makes it out like you should only use that button in an emergency (I saw in a MEP816A tech manual they have the same button and it's called the Battle Bypass or something severe like that. Meant to be used only during dire emergencies like the genset is overheating but you need it to run _just_ a few more minutes so your radio operator can get out the coordinates). Anyway, the bypass button is supposed to bypass the failsafes, which are:

1. Oil Pressure Switch (on oil filter housing)
2. Thermo-Switch (on thermostat housing)
3. Thermo-Switch (on radiator)
4. Thermo-Switch (on water-cooled exhaust manifold)
5. Thermo-Switch (on oil sump)

Switches tested as follows:
1. Normally open
2. Normally closed
3. Normally open
4. Normally open
5. Normally open

I'm not sure what sequence the failsafe wiring goes. A wiring diagram would be super handy right now. The #2 switch tested normally closed so I thought that was the culprit but when I removed the wires the overheat dummy light illuminates on the panel so it must be normally closed. I meant to test all of the switches for 12v on one wire but I got too cold. The oil pressure switch has 12v present and the #2 thermo-switch had 12v present. I will test for voltage at the other switches tomorrow.

The shutdown system on this machine consists of an "energize to shut-down" solenoid run by a 10 second timer relay. The timer relay gets it's signal when voltage is taken away from the "brown wire" as far as I could tell. When I mash the bypass button the brown wire would show 12v, when I let off it goes to zero and the big shutoff solenoid trips for 10 seconds to shut down the engine. Just typing all this out makes me now think all of the thermo-switches are broken! I'll jumper all of them at the same time and see if that gives 12v a path to the "brown wire". Of course Fischer used a hodge-podge of black/white/blue wires everywhere so I've no idea where things go.

I spent a few hours out in the cold squatting on the ground chasing wires until my hands were numb. I'm pretty bummed about this thing. I could rig up the bypass button as a toggle switch but then if something happens while it's running it wouldn't auto shut off and I'd be super screwed.

I've been sitting here for several hours now searching for tractor and other generator wiring diagrams just to find something similar. It makes sense to me that if you have to have 12v applied to a relay to keep it from firing (10 second timer relay) then all your fail-safes should be in the closed position during operation to allow 12v to get to that relay. When one "pops" it breaks 12v to the relay and trips shutdown. Another thing to think about is the soft-button panel. It doesn't make sense. Pushing the "on" button makes no relay noises but does send 12v to the terminal block above the relays. I tried jumping one of those switched 12v to the brown wire but it did nothing. Mind you when I jumpered it to the brown wire I actually de-pinned the brown wire to remove it from the system in case of a ground problem. Again, I wish I could get a wiring diagram!!


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## Greasysidedown (Aug 24, 2021)

Little update. Me and a friend sat down and did some troubleshooting after I found a diagram for the remote panel in the manual (it was lurking in the remote start section in the back of the manual). Discovered the fuel pump relay also triggers the shutdown solenoid timer relay. The trigger wire for the fuel pump relay was not getting power from the remote panel softkey (panel has tiny surface mount relays that do this switching) Found a wire on the distribution block that DID function with the softkeys and switched it over to the fuel pump. Now it starts, runs, and stops as it should but there is a fault light present, presumably for where I took the wire from. That is the next step, that wire seems to be shorted to ground and we weren't able to troubleshoot it. This weekend is looking sunny so I'll give it a stab.


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## ToolLover (Jan 13, 2020)

Good troubleshooting. Keep going you are just about there.
I worked on a complicated machine made by Hauni and it too had the wires terminated in hidden places then had the wire numbers changed. Without the wiring manual it was impossible to trouble shoot it. We had the good fortune to find a manual left on the table and copy it which put us in better shape.


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