Goofy4TheWorld Show full post »
78buckshot
You may be right Peddler, I don't remember seeing any with the holes that close to the center of the hub but the older ones might be. Goofy, you might just as well put it together with what you have, if it fails it won't do much harm to anything.
Quote
Goofy4TheWorld
I already have it back together, I am focusing on this fan in my consideration of whether or not the dealer I hired screwed me.  With what appears to be puller holes that were never threaded, I am wondering whether or not they even pulled the fan, or when they saw the threads missing, decided to just change the brushes and reach behind the fan to clean the rings with a rag as best they could without removing the fan.  I guess I am curious if it's possible that they could have removed the fan WITHOUT the holes being threaded, perhaps they had a trick to doing it based on their experience?

Even if they did pull the fan, I have very little doubt that they did NOT fully expose the rings by removing the housing like I did, which is why I think they used a rag to wipe the rings while they spun it around and called it a day.  They weren't there long enough to have pulled the end off IMHO.

And I think all of this explains why they wouldn't call me back unless I hounded them, and then wouldn't call to set up a new appointment like they promised.

Maybe they did do what they were supposed to do (except for sanding the rings, which they admit they never did), but I am growing more skeptical that they performed the work as expected.

It's all water under the bridge for now though, and I will have to give it 12 months before I pull out the Mission Accomplished banner.  But if in 12 months the thing is still working, I will be convinced the dealer screwed me.
Quote
78buckshot
The only fan I have taken off without a puller was on an eight kw, I kind'a doubt they had it off on your machine.
Quote
Goofy4TheWorld

After going back and re-reading this entire thread, I have confused myself. Back on November 11, 2018 while posting about the day the dealer came I said that "I saw the rings before they were cleaned, and both the rings and that whole end of the alternator were covered with a heavy black film, but the rings were otherwise intact and not worn or deformed."   Boy I have NO recollection of seeing the rings, and I really wonder if what I looked at back then was even the rings.   Two moths later I posted that I did NOT see the rings, but that was all the way back in April 2018 and I just can't swear what I saw at this point, so I am going to give the dealer the benefit of the doubt.

Last week, while waiting for help trying to figure out how to remove the fan, I had time to kill and I put my ohm meter back on wires 0 & 4 at the voltage regulator to see where it stood before I touched the brushes. It read 21 ohms at first, but then I realized that with the top cover now off of the fan I could easily spin the generator around and see if the ohms varied. I was stunned to see ohm readings jump as high as 110 ohms at some points in the rotation. It probably was about equally divided between reading 21 ohms and then reading 110 ohms, and I got these readings consistently over multiple cycles of the fan. I was turning it just a tiny bit then stopping to see the reading, then I would turn it again just a tiny bit and read it again, probably watching it for 15 minutes while I had free time. Seeing this made me feel like I was chasing the right rabbit, that the brushes or the rings were my root cause. After my final reassembly I checked it again and it stayed right at 21 ohms all the way around!

Back in January 78buckshot asked me if the dealer used washers to shim the brushes. After now removing them myself I can say that there were no washers installed. I am not sure that washers would have been needed since I think washers are used to correct brushes not riding on the rings on-center, and my pictures clearly show the black on the rings was dead-centered.

I wish I had re-read this thread before the tear-down, I completely missed 78buckshot talking about how the dealer should have measured ring to ring AND ring to ground resistance.   I could have easily done that during one of my THREE teardowns! I am curious though, what would those readings tell me about my generator?

While I was sanding the rings I thought to myself "you know, this could possibly get these things out of round"..... but I just kept sanding thinking I had nothing to loose. I am not sure what Wirefoam is describing as his technique for avoiding the pits. My technique was I cut the sandpaper into 12" long and probably 1.5" wide pieces and I sanded the rings in halves, where I would sand the top half, then turn the paper in quarter-turns to try to keep a continuous amount of pressure to the rings as I traveled around them. I probably sanded them a little too much though, I have a tendency to over-tighten, over-sand, and over-paint stuff! I just hope I didn't get them too much out of round.

After tearing it all back apart to repair my broken rubber foot I borrowed a torque wrench for the reassembly. I was surprised at how tight these readings were, the torque wrench had me tightening them tighter than I would have tightened them on my own.

While tearing it down this last time I found where I had left a bolt out, and this missing bolt would not have contributed to my "thump", so I am not sure what was going on there. After my most recent reassembly the thump is MUCH improved, with only a tiny bit of contact with these two metal sheets over the muffler.

I want to thank everyone who contributed to this thread and read through my manifestos. This was a job well beyond my pay grade, but if in 12 months this thread remains cold it will be worth all the hard lessons learned!

Quote
Goofy4TheWorld

Well I had a reminder set in my calendar for April 4, 2020 to remind me to return to this thread, certify that the thread had remained dead for one year, and then declare victory over the demons in my 4390.

Unfortunately my demons have returned!

Over the past several weeks I have observed the following:

For the first time in about 6 months, I found another flashing over speed error after realizing the generator wasn’t running at its set exercise time. I went outside and cleared the error and attempted a manual start, and it again went into flashing over speed. A second attempt at a manual run was successful (so it started on the third attempt including the initial exercise attempt).

After this I manually started it every day for about 5 or 6 days, and it started on the first attempt on all of those starts (so no shutdowns).

After this run of 5 or 6 days of manual starts, when the unit was due for another exercise on day 7 it ran the exercise without any errors.

After this successful exercise I stopped running any manual restarts. The generator then failed to exercise on day 14 (and I was gone that day and didn’t know it until day 15). So on day 15 I cleared the over speed error and attempted to reset the exercise cycle and just move my exercise time up a day. The generator failed again on my first attempt to restart, but started and ran successfully after my second restart (so once again in starts on the third attempt in total, spanning the 24 hours).

I let it go another 7 days, and on day 22 (today) the generator again fails to start during exercise. It again takes me two restarts to get it to work.

I am all ears on suggestions for what I should do next, or educated speculations about what I may find if I tear it back apart and how to diagnose it once I start in on this. I assume I will tear the generator back apart and see what my rings look like. Before doing that I may try to take some ohm readings while moving the fan around to see if, like I did back in April, I see dramatic increases in ohms during some portions of the revolution, (although I can’t remember if I can turn the fan without tearing it down or not???).

I have also checked the naughty list, and it appears I have some issues to address before asking Santa for a new generator. My recent history does not bode well for my chances of receiving one this Christmas.

I am also going to ask around about the price of scrap metal!

As always, any advice would be greatly appreciated.

Quote
Peddler
Clean the slip rings and then if it continues put a continuous field flash kit on and it will solve that problem.
Quote
BrianMartin
Peace of mind is worth a lot in my book. After all of these headaches, I would have put in a new machine, with a 7 year warranty. Just my 2 cents!
Quote
Goofy4TheWorld
Today it again failed to start at exercise time and, and again rt restarted after two more attempts.  I let it ran a few minutes in manual, and then I decided to let it stay running and simulate an outage by killing the feeder breaker.  While it was still running in manual I first killed the sub-panel breaker, then I went to the generator and switched it from manual to auto, and after about 20 seconds the transfer switch moved to generator power and the generator immediacy shut down.  My generator doesn't have any motor loads other than a refrigerator and a furnace fan, so it wasn't overloaded.  I can only assume that this is a clue as to what is wrong with this thing, but because I was so caught off guard by the shutdown I restarted the thing without fully noting the status of the LEDs, so I can't say for sure what the shutdown indicated on the 4 LEDs.  After I restarted again it stayed running for 90 minutes under load.

But this was the first time it has EVER shut down after running more than 2 seconds, and the first time EVER it has shut down as soon as it was hit with a load.
Quote
ohmslaw
Peddler wrote:
Installing a field boost kit is probably what I would do if the problem persists as it seems to be doing.  The down side of the field boost kit is that if the VR fails you still get about 60-90 volts L-L and when the transfer relay calls for transfer it isn't enough voltage to pull the switch over but it will slowly (within a few seconds to a couple minutes) cook the emergency coil in the switch.  There are ways to protect against this but it gets more complex.

We install FBK's frequently with a 100 percent cure rate. The liquid cooled units come from the factory this way. I couldn't understand why Generac wired the Air-cooled differently.
Tim
Quote
Goofy4TheWorld
Is this it https://www.zillerelectric.com/products/generac-0h07850srv-field-boost-upfit-kit?_pos=3630&_sid=744f3e05e&_ss=r ?

If it is, I feel stupid for not already doing this.  For some reason I thought they were several hundred dollars, and I wasn't sure how much money I was willing to sink into Bess.  But for $80 I'll go for that easy!
Quote
murphy
That is it.  I put one of those on my 2006 7kW generator.  It cured the lack of power generation because the rings  had water (condensation) or ice on them.  The 2006 was a dumb generator. It didn't know that it wasn't generating power.
Quote
Goofy4TheWorld
I have purchased it now, and I see on the product page that it says "If you need a wiring/install diagram for this, please request one as we have them available"...

So if Geoff Z sees this post, can you send me the installation instructions for a 4390?
Quote
Goofy4TheWorld
I have now installed the continuous field boost kit.  Of course the generator starts right up, and it has now passed it's first exercise cycle, but I will have to wait several months before I know if this is a consistent fix.  I have been tricked way too many times to declare victory now.

I plan on posting my experience (with pics) insatlling the field boost kit as soon as I get the time.  I am amazed that I have found almost ZERO posts or ABSOLUTELY NO YouTube videos about installing them, and these things are not for the faint of heart to be installing blind!
Quote