Title: Kubota electrical generation failure
Post by: Michelle on September 15, 2010, 05:19:19 pm
Post by: Michelle on September 15, 2010, 05:19:19 pm
One small point I should make. If you start to add up the hours on the generator, we have found that before 5 k hours, need to replace the sealed ball bearing that holds the end of the generator, not engine end. Not a big deal to replace.
Very costly when that bearing goes bad and drops the rotor into the stator.
Dave,
Got a question on this one for you. '03 with the Kubota 10KW in the quiet box,about 500 hours. No output whatsoever.
MOT and PowerTech discussions (after ruling out any sense wires or the voltage regulator through probing in a few locations) that it's likely (if I'm remembering correctly; I was a bit stressed since this was found as we were wrapping up to leave Nac this morning) something termed "exciter stator". Of course they have to pull the genset and open it up to see if anything else will be on the parts list - would this be related to that bearing? We had no warning, certainly nothing that sounded like a bearing failing and no voltage fluctuations. Only a slight rattle that sounded like a loose cover.
Thoughts, ideas, miracle cures?
Michelle
Title: Re: Kubota electrical generation failure
Post by: Dave M (RIP) on September 15, 2010, 06:12:07 pm
Post by: Dave M (RIP) on September 15, 2010, 06:12:07 pm
Michelle, If they are going to remove from the compartment, surely check the end bearing for play, damage. I doubt the bearing is faulty with 500 hrs. Other possibilities are the exciter stator windings, exciter rotor windings, main rotor and or main stator windings.
Hate to hear of your problem with the genset.
I can forward a wiring diagram for that model if it is like mine.
Will forward the resistance chart by email, do not know h ow to do it here.
Dave
Hate to hear of your problem with the genset.
I can forward a wiring diagram for that model if it is like mine.
Will forward the resistance chart by email, do not know h ow to do it here.
Dave
Title: Re: Kubota electrical generation failure
Post by: Dave M (RIP) on September 15, 2010, 06:31:25 pm
Post by: Dave M (RIP) on September 15, 2010, 06:31:25 pm
One more thought, if it is mechanicaly ok, just put a 9 volt battery across the F+ and F- leads to exciter, it will build voltage, if not then look deeper into the resistance readings, both rotors and both stators.
Dave
Dave
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 15, 2010, 06:39:41 pm
Post by: Michelle on September 15, 2010, 06:39:41 pm
Thanks, Dave!
At least one of the measurements made was resistance across 2 of the pins of a connector that go to the voltage regulator, and the result was 92.4 ohms. That value seemed to rule out the main rotor/stator, from what I could hear on this end of the phone consultation with PowerTech.
They also applied dc voltage directly to the exciter while the genset was running (engine mechanicals seem perfectly fine) but got no output.
Any insight into why windings might be quite so short lived? Materials defect? Mike is going to take lots of photos and save the parts for us.
Apparently the genset has to be removed in order to get to the parts in question - if you are familiar with that unit and have a less labor-intensive/costly way to access given the quiet box, it would be much appreciated! MOT is going to do what they can to minimize the pain, but it's still quite a few hours.
You can attach files to posts here by clicking the "Additional Options...." that's just below the posting box, then use the "browse" next to the Attach box to find the file on your computer to attach.
We much appreciate any info you might be able to share.
Michelle
At least one of the measurements made was resistance across 2 of the pins of a connector that go to the voltage regulator, and the result was 92.4 ohms. That value seemed to rule out the main rotor/stator, from what I could hear on this end of the phone consultation with PowerTech.
They also applied dc voltage directly to the exciter while the genset was running (engine mechanicals seem perfectly fine) but got no output.
Any insight into why windings might be quite so short lived? Materials defect? Mike is going to take lots of photos and save the parts for us.
Apparently the genset has to be removed in order to get to the parts in question - if you are familiar with that unit and have a less labor-intensive/costly way to access given the quiet box, it would be much appreciated! MOT is going to do what they can to minimize the pain, but it's still quite a few hours.
Quote from: Dave M
Will forward the resistance chart by email, do not know how to do it here.
You can attach files to posts here by clicking the "Additional Options...." that's just below the posting box, then use the "browse" next to the Attach box to find the file on your computer to attach.
We much appreciate any info you might be able to share.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Dave M (RIP) on September 15, 2010, 08:09:45 pm
Post by: Dave M (RIP) on September 15, 2010, 08:09:45 pm
Michelle, the resistance across F+ & F- is listed at 87.4 ohm for the 10 kw.
Would love to send youy this manual, has all the info.
Dave
Would love to send youy this manual, has all the info.
Dave
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 15, 2010, 09:46:53 pm
Post by: Michelle on September 15, 2010, 09:46:53 pm
Michelle, the resistance across F+ & F- is listed at 87.4 ohm for the 10 kw.
Would love to send you this manual, has all the info.
Got it - thanks!
As a genset guru, would you take 92.4 ohm when it's 95 degrees outside to be "significantly different" than 87.4 ohm at the 77 degrees the manual says ambient measurement temperature should be? I'm assuming the measurement was the exciter stator (F+ F-), not the main stator (U1 V1 or U2 V2) or either rotor, of course since the info relayed to PowerTech resulted in their diagnosis of exciter stator.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 15, 2010, 11:15:40 pm
Post by: Michelle on September 15, 2010, 11:15:40 pm
I think you are ok with your reading, I would use the 9 volt battery across those two leads, assuming they are the F leads.
I would bet you get about 110 volts using the battery, no load, turn off fan etc.
If you do get the voltage, the regulator is the problem or the wiring came loose etc. Not a major issue.
Sadly, using an applied voltage ("power probe") no output voltage. But not sure on the load - I don't know if they had the breakers off or not but I suspect not. They did try bypassing the regulator and even trying a new regulator and still no voltage.
I would still like to think a loose wire somewhere, though, so I will mention the 9V battery application in the AM - maybe we can check that before we leave. I would hope that a winding wouldn't fail so completely that we wouldn't have had some kind of warning sign.
Quote
By the way, Barry sent me the manual a year or so ago, I gotta have info for my toys.
We happened to mention the forum to a potential member yesterday, and he wanted to make sure Barry was an active member :)
-M
Title: Re: Kubota electrical generation failure
Post by: Dave M (RIP) on September 16, 2010, 06:48:18 am
Post by: Dave M (RIP) on September 16, 2010, 06:48:18 am
The 9 v battery is the standard test, it just tests if the generator is capable of making voltage or not.
By replacing the regulator may or may not solve anything. If the battery works, I would be looking for a bad connection.
Note, the 9 v battery will not power up the fan or any other load, turn off the breakers (2) and off on the fan breaker.
Then check voltage at genset side of breaker, not load side.
If still dead, you gotta problem inside the generator .
Luck indeed
Dave
By replacing the regulator may or may not solve anything. If the battery works, I would be looking for a bad connection.
Note, the 9 v battery will not power up the fan or any other load, turn off the breakers (2) and off on the fan breaker.
Then check voltage at genset side of breaker, not load side.
If still dead, you gotta problem inside the generator .
Luck indeed
Dave
Title: Re: Kubota electrical generation failure
Post by: John S on September 16, 2010, 07:56:13 am
Post by: John S on September 16, 2010, 07:56:13 am
Wow, I learned a lot on this thread that I hope I have no need to ever figure out.....
Title: Re: Kubota electrical generation failure
Post by: Dick S on September 16, 2010, 10:51:27 am
Post by: Dick S on September 16, 2010, 10:51:27 am
Dave,
I would like to get a copy of that manual too if possible. Thanks.
I would like to get a copy of that manual too if possible. Thanks.
Title: Re: Kubota electrical generation failure
Post by: Peter & Beth on September 16, 2010, 12:29:53 pm
Post by: Peter & Beth on September 16, 2010, 12:29:53 pm
Dick, Glad to provide the info for the Kobota Power Tech 8, 10 and 12 kw Gensets.It covers the models with the newer non digital display and have the sound box housing. Not sure about other Power tech models.
Be glad to share it with anyone needing it
I just need a Email address to send it to. It is a 12.2 meg file
As demonstrated earlier, I have no skill to put it here. wg4t@genset.com
Dave
Don't be intimidated...
Reply to this post. Then scroll down the screen until you see "Additional Options..."
Then, you'll see "Attach: "...select Browse.
find the fie for the Manual in your computer directories & "Open" it to attach it to the post.
Done...
Hit "Post"
Title: Re: Kubota electrical generation failure
Post by: Peter & Beth on September 16, 2010, 01:13:16 pm
Post by: Peter & Beth on September 16, 2010, 01:13:16 pm
Yikes! Maybe Michelle or Steve can shed some light on the subject. The file may be too large for the ForeForums to accept?? :o
Title: Re: Kubota electrical generation failure
Post by: Peter & Beth on September 16, 2010, 01:42:29 pm
Post by: Peter & Beth on September 16, 2010, 01:42:29 pm
Dave,
My 8KW PT uses an Isuzu diesel engine. And, I believe I also don't have a manual...don't recall ever seeing it, but the coach is in storage.
Others may want to send you their email if they are interested in getting the manual.
p.s. My email is part of my signature box, so anyone can always send me an email if they choose to. No nasties, please... :o
My 8KW PT uses an Isuzu diesel engine. And, I believe I also don't have a manual...don't recall ever seeing it, but the coach is in storage.
Others may want to send you their email if they are interested in getting the manual.
p.s. My email is part of my signature box, so anyone can always send me an email if they choose to. No nasties, please... :o
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 16, 2010, 04:08:42 pm
Post by: Michelle on September 16, 2010, 04:08:42 pm
Maybe Michelle or Steve can shed some light on the subject. The file may be too large for the ForeForums to accept?
Yes, that's the case - the file is too large for a user upload (the server won't accept it). Since we now have a copy, Steve will put it up for download.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 16, 2010, 04:33:59 pm
Post by: Michelle on September 16, 2010, 04:33:59 pm
The 9 v battery is the standard test, it just tests if the generator is capable of making voltage or not.
By replacing the regulator may or may not solve anything. If the battery works, I would be looking for a bad connection.
Note, the 9 v battery will not power up the fan or any other load, turn off the breakers (2) and off on the fan breaker.
Then check voltage at genset side of breaker, not load side.
If still dead, you gotta problem inside the generator .
Thanks, Dave. I don't know if the power probe they tried duplicates this or not (I expect so, I believe it was 12V DC and applied to the exciter stator F pins), but I've forwarded your suggestion to Mike Rodgers as one last try in hopes of a loose wire before they pull the genset out of our coach. I'm pretty sure the breakers hadn't been off when the testing was done, and if there's a chance that would have affected the result, it's worth a recheck.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 16, 2010, 04:42:21 pm
Post by: Michelle on September 16, 2010, 04:42:21 pm
the file is too large for a user upload (the server won't accept it). Since we now have a copy, Steve will put it up for download.
Done AND he crunched it down to below 5M.
Title: Re: Kubota electrical generation failure
Post by: Gary Bouland (RIP) on September 16, 2010, 07:25:54 pm
Post by: Gary Bouland (RIP) on September 16, 2010, 07:25:54 pm
You can never have too much info. It looks like the Powertech Manual does not apply to the older units.
Does anyone have a manual for the PTS MH 10 FT ? From the model number it appears that this may be a special model built for FT. This is the older 4 cylinder Kubota that is not mounted in a box.
Does anyone have a manual for the PTS MH 10 FT ? From the model number it appears that this may be a special model built for FT. This is the older 4 cylinder Kubota that is not mounted in a box.
Title: Re: Kubota electrical generation failure
Post by: Dave Head on September 16, 2010, 07:49:40 pm
Post by: Dave Head on September 16, 2010, 07:49:40 pm
Quote
On 9/16/2010 7:25 PM, Gary Bouland wrote:
You can never have too much info. It looks like the Powertech Manual does not apply to the older units. Does anyone have a manual for the PTS MH 10 FT ? From the model number it appears that this may be a special model built for FT. This is the older 4 cylinder Kubota that is not mounted in a box.
Gary B 95 U280
Title: Re: Kubota electrical generation failure
Post by: Mike Baldacchino on September 16, 2010, 10:12:38 pm
Post by: Mike Baldacchino on September 16, 2010, 10:12:38 pm
Gary,
My gen set is a PTS MH-10 FTRR and I have the manual in front of me.
My gen set is a PTS MH-10 FTRR and I have the manual in front of me.
Title: Re: Kubota electrical generation failure
Post by: Brad on September 18, 2010, 10:17:16 am
Post by: Brad on September 18, 2010, 10:17:16 am
Steve,
Any final resolution with the gen? It sure seems if the windings have failed at such low hours it has to be a manufacturing defect. If that is the case, a letter to Power Tech might help with a least some cost.
Good Luck,
Brad
2000 U320 4000
Any final resolution with the gen? It sure seems if the windings have failed at such low hours it has to be a manufacturing defect. If that is the case, a letter to Power Tech might help with a least some cost.
Good Luck,
Brad
2000 U320 4000
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 18, 2010, 11:22:53 am
Post by: Michelle on September 18, 2010, 11:22:53 am
Any final resolution with the gen? It sure seems if the windings have failed at such low hours it has to be a manufacturing defect. If that is the case, a letter to Power Tech might help with a least some cost.
No news yet. Mike Rodgers is going to recheck the exciter response with the breakers off (load removed) as Dave M. indicated. He'd had the Power Tech folks on the line while he was doing the original check, so we're hopeful, but it doesn't look very promising.
We (including Mike) definitely plan to be talking with Power Tech on this one if it does turn out to be something like one of the windings.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Michelle on September 18, 2010, 01:23:41 pm
Post by: Michelle on September 18, 2010, 01:23:41 pm
Additional thoughts on the problem,
1-Residual voltage? with breakers off, what AC Voltage does it produce, hopefully 5-10VAC
IIRC no voltage with the breakers on. Even Mike said it should have output something. I don't think he's had time to break away and recheck with breakers off. They are absolutely swamped there.
Unfortunately, coach is in Nac, we are back home in Denton now waiting for a slot to open so they can work on it so we can't check this ourselves.
Quote
2-Surely the engine is turning over at the 1800 RPM-60 Hertz area, easy check, even with very low voltage, it will register the frequency/hertz on the ac line with a VOM that has freq sensing.
This one I don't know the answer to. Mike was doing a lot of probing of the regulator connector while on the phone with the Power Tech guy.
Quote
it is not a complicated issue for genset folks.
Too bad you're not in Nac and bored with nothing to do ;) I will forward your ideas on to Mike, though.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Dave Katsuki on September 19, 2010, 12:46:57 am
Post by: Dave Katsuki on September 19, 2010, 12:46:57 am
We have an Power Tech 8kw Isuzu in our 99 U270. Any chance that anyone has a manual for that one?
Thanks!
Thanks!
Title: Re: Kubota electrical generation failure
Post by: Michelle on October 08, 2010, 10:07:05 pm
Post by: Michelle on October 08, 2010, 10:07:05 pm
Posting a followup now that the diagnosis and repair (mostly - the genset needs to be reinstalled in the coach) are complete.
Apparently the exciter rotor was loose. Something that should not ever happen and can't be explained. It took out pretty much everything else in the generator end. Oh, and if I hadn't mentioned it earlier, the 10 kW generator end is no longer available, a 12 kW (at higher cost) has to be installed in its place along with a new voltage regulator in order to ensure warranty. Fortunately the Kubota engine for the 10 and 12 kW units are the same, so it should be no additional stress on the engine. Small comfort there.
We will be politely following up with Power Tech since this was clearly a manufacturing defect somewhere.
Michelle
Apparently the exciter rotor was loose. Something that should not ever happen and can't be explained. It took out pretty much everything else in the generator end. Oh, and if I hadn't mentioned it earlier, the 10 kW generator end is no longer available, a 12 kW (at higher cost) has to be installed in its place along with a new voltage regulator in order to ensure warranty. Fortunately the Kubota engine for the 10 and 12 kW units are the same, so it should be no additional stress on the engine. Small comfort there.
We will be politely following up with Power Tech since this was clearly a manufacturing defect somewhere.
Michelle
Title: Re: Kubota electrical generation failure
Post by: Barry Beam on October 08, 2010, 10:14:45 pm
Post by: Barry Beam on October 08, 2010, 10:14:45 pm
Quote
We have an Power Tech 8kw Isuzu in our 99 U270. Any chance that anyone has a manual for that one?
Do you still need the generator manual?
I have acquired one for you here at the 4 corners rally.
I have made a copy of the manual but have to scan the copy when I get home at the end of the month & can email it if you need it.
Title: Re: Kubota electrical generation failure
Post by: Dave Katsuki on October 10, 2010, 03:30:23 am
Post by: Dave Katsuki on October 10, 2010, 03:30:23 am
Thanks, Barry, I would love to get a copy of the manual! Perhaps Steve can also get your copy put up on the site as he did for the 10 kw Kubota?
Title: Re: Kubota electrical generation failure
Post by: Michelle on June 10, 2011, 11:41:52 am
Post by: Michelle on June 10, 2011, 11:41:52 am
Apparently the exciter rotor was loose. Something that should not ever happen and can't be explained. It took out pretty much everything else in the generator end.
Just bumping since I finally got a YouTube video of the "remains" that I can send to PowerTech. Very delayed but worth a try. Only about 500 hours on the genset :-(
! Service Unavailable (http://www.youtube.com/watch?v=AxetImcO-ZI#)
The still photos are here:
Michelle