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Vans 60amp Alternator Failure with EXP2 DC Load Center (over water)

Jon Clements

Well Known Member
Last Wednesday I flew from Melbourne to Hobart in my RV-7 (about an hour of the 2.5hr flight is over water - Bass Strait). Faultless day, faultless flight. Yesterday I jumped in my RV and flew from Hobart to Bruny Island (short flight - no problems). When I departed Bruny Island I got a Low Voltage Warning on my EFIS a couple of minutes after take off. I have an EXP2 Buss DC Load Center with indicator panel and GRT EFIS. EXP2 Indicator panel showed that the Alternator had switched off and the GRT was showing 13.3Volts and dropping. I know you shouldn't turn the alternator off when the engine is running however I cycled the Alt Switch to see if i could get it to reset but no change resulted. At this point I was over water so I requested a direct track to Hobart and landed to check it out (while I still had some volts). By the time I landed I didn't have enough volts to start the engine. I recharged the battery overnight. This morning I started the engine and the Alternator came back on line and operated as normal. After warm ups I obtained a clearance and departed Hobart....3 mins later the Alternator failed again and I returned to Hobart. Before I shut down I momentarily switched the master switch off and then immediately back on - this recycled the alternator and it was operating normally again. I suspected it may have been an over voltage condition because the EXP2 Buss has over-volt protection which turns off the Alternator and you have to remove battery power to reset it. I did a ground run for approximately 3 minutes at 2200rpm but it continued to operate normally (i thought this might cause it to fail). I shut down and removed the cowls and checked the belt and checked the connectors. Removed and refitted the connector on the back of the Alternator - all seemed fine. Following this I replaced the cowls and then inspected the EXP2 Buss to see if there were any loose connections. All seemed OK. I started the engine again and Alternator was operating normally after run-ups and a higher rpm check. I taxied out to the runway and I watched the indicator panel on departure...shortly after take off (before I had reduced the rpm) the indicator panel showed a high voltage warning which then reverted to a low voltage warning probably due to over volt protection kicking in. I completed the circuit and landed, tied down my RV and came to the conclusion that I wasn't going to fly back over Bass Strait in a hurry so I jumped on a commercial flight home.

So now the dilemma - I didn't bring the Alternator home with me so I can't bench test it. My thoughts are to purchase a replacement alternator and take it to Hobart and fit it to see if the problem goes away. If not, then I will have a spare alternator and the problem is more likely to be a fault in the over volt protection on the EXP2 Buss.

Has anyone had a similar experience with the Vans 60amp Alternator and EXP2 Buss combination? If yes - what conclusions did you come to?

I have had a previous Internal Voltage Regulator failure with this same Alternator which was repaired. I believe the previous failure may have been caused by turning on the alternator switch after start up. Ever since that point I have been turning on the Alternator switch prior to start up and turning off after shutdown.

My Engine/Alternator has now done 193 hours.

Any help/thoughts would be appreciated because when I fly back to pick up my RV I want to be confident that I can get it home.

Also - does anyone know if the Plane Power 60 amp alternator is a direct swap (using same brackets and connector wiring/plugs)?

Thanks

Jon
 
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Jon, you can borrow my alternator for the trip back if you want. Not sure the plug is the same but could make up a adaptor.
Just a thought on the power panel, does it switch off the field power to the alternator or does it simply disconnect the charge wire from the alternator to the panel / battery when it senses a over volt? may be both?

Mick
 
Is this the Plane Power 60 amp alternator?

I had this happen at about 75 hours and just the other day (920hrs) and can't fault it now. I just let it go and recycled the field about 5 minutes later. I am not a fan of multiple resets in quick succession for the obvious reasons.

Jamie Lee had a similar occurence around 10 weeks ago (about 180 hours) and it has been fine since.

The only protection built in is over voltage and it is supposed to trip the field C/B.

Apart from a rubbed wire? It is hard to say. :confused:

Lets keep track of this for a while.

I have purchased a new set of brushes and regulator, next time the cowls are off it is getting some TLC.

One last point, we did find a bit of oil from a small leak around Jamies Alternator, oil moves around in strange ways under there, so we cleaned it out with contact cleaner. Maybe that is a clue?
 
Hi Dave

Not a Plane Power Alternator. It is the stock Vans 60amp Alternator that they supplied with the FF kit back in 2006 - Nippondenso from memory. Vans no longer supply these (I suspect due to numerous failures) and they now supply Plane Power I believe.

I discussed this further with Mick Haynes today and I am suspect that the internal Voltage regulator has quit again. When I recycled the over voltage protection (by turning the Master Switch off) it came back to life but was only putting out about 13.6V at 1500rpm. The last time test flight I did I watched the indicator panel for the EXP2 DC Load Centre and it definitely showed a high voltage warning before the alternator went off line (and then the subsequent low voltage indication with the Alt light indicating it had switched off). Cycling the Alt switch (field) would not restore it which suggests the Overvolt protection had kicked in.
My internal VR failed at about 85hours and it has now done approx. 193 hours. I suspect it may have failed again....Mick suggested that it might be getting cooked due to limited airflow through the cooling tube....I suspect he is right.

Thinking I will head back to Hobart with Mick's Alternator as a back up plan for a swap out to get it home.

Thanks for your quick response.

Cheers

Jon

By the way: Looking at your total time you must be spending more time in your RV10 than you are at work ..... ;) I am impressed!
 
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I had something similar

we have the stock Vans 60amp and the EXP2bus in 705RP.

When mine failed, i was able to reset it a couple times with the alternator field switch but it stopped working again after just a few minutes. We have the B&C 8amp backup alt which i used to get home. took the main alternator to the local shop and they said it was bad, replaced with a new one from Oreilly autoparts and it has been fine ever since.

We never switch our alternator on or off when the motor is running anymore.

Sorry, but I do not have the part number but i was able to get it by searching the posts here on VAF.
 
Hi Jon

My hangar mate & I struggled for years with the Nippon Denso alternator I purchased from Vans in 2006 (both on Rv-7As) we both have replaced these alternators many times with the same type over a 6 year time frame due to over voltage issues

Through research & testing we have concluded that the internal regulator detects the voltage from the field wire. Therefore if you have any voltage drop in you aircrafts wiring system that then feeds back to the IR, you IR is lied to from the field wire and thus increases the output voltage & overvoltage is the result. In your case you stated your system self detects overvoltage & shuts off your alternator

In our research we discovered the Vans supplied alternators came with IRs which are "Transpo IN253". There are 3 spade connections on these IR "plugs". These are for field wire, a trouble light, and a voltage sensor. What we found out is there are 3 different varieties of the sensor lugs which are "Dummy", "Computer", & "Sensor"

We would pull the alternators from our RVs & get them tested & they would bench test fine.

The cure for us (still testing but seemed to fix the problems in both RVs), was to purchase the "sensor" IR & run a short wire from the charging lug to the "sensor" spade connector on the new IR

The "sensor" Internal Regulator is a Transpo IN256

Best of Luck with your situation,
Clark
 
I had this same problem intermittently for several months. I replaced the alternator, all of the wiring, all of the connections. I bypassed the EXP2. Every time I worked on it the problem would go away and then come back within a few hours. - It turned out to be the plug in the back of the alternator that supplies reference voltage (for the internal voltage regulator)coming loose. - It does not take much.
I secured it better and have gone a year+ with no issues.
Let us know what you find. I hope it is this simple for you.
 
Bad Regulator

I've gone through a few ND55s over the years. The first one lasted 600 hours. The second one only 200 (was still under warrenty when I replaced it), and the rest have been everywhere in between. I'd upgrade to the Plane Power, but the ND55s are so cheap and available, and my panel so basic, I haven't been able to talk myself into it.

So to me it sounds like you have a bad internal regulator. Head on over to whatever the Australian equivelent of CarQuest is, pick up a remanufactered 14684 (should be about $80 US or less), and you should be good. Then you can bring the old one back for the core credit.

Good luck!

-Matt
402BD
 
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EXPBUS OVP Reset

For archives...

Sounds like it my not be your EXP if you reset it.

If you have the Bus2 installed and do not have your papers handy, this info might help.

Here is a written instruction from the manufacturer:

?If the Over Voltage Protection circuit trips and shuts the field off, you will have to service the problem that caused the condition and then reset the circuit by one of the following means: disconnect the battery with the engine off, or remove the black shunt jumper [on circuit board] momentarily and replace, or IN THE CASE OF THE OPTIONAL OVP RESET BUTTON the pilot pushes the button for a short moment then releases.?

I have installed an optional remote OVP reset switch on my panel, but fortunately have not had to use it approaching 300 hours. If you run without their optional indicator panel, as I do, the only indication of the need to reset the OVP would be a lighted LED on the circuit board, which is impossible to see in most installations.

Below is the procedure for installing the remote switch, as written in the manufacturer paperwork. If you need a copy for EXPBUS2, contact me offline at [email protected]:

?The second option is the installation of a remote mounted switch to reset the OVP protection feature. To do this the installer must connect a normally closed momentary pushbutton to pins 3 and 4 of the J29 connector, in place of the black shunt jumper. When the circuit is closed, the OVP feature is enabled and armed, when the circuit is open the OVP is disabled and reset?.

Mike Bauer
RV6 N918MB
 
What is the logic in not turning the generator off or on with the engine running? I have been in the habit of not turning on the generator until after engine start and have not had any issues. FYI, I have a fairly simple electrical system and am not using the EXP setup.

Thanks!
 
I've gone through a few ND55s over the years. The first one lasted 600 hours. The second one only 200 (was still under warrenty when I replaced it), and the rest have been everywhere in between. I'd upgrade to the Plane Power, but the ND55s are so cheap and available, and my panel so basic, I haven't been able to talk myself into it.

So to me it sounds like you have a bad internal regulator. Head on over to whatever the Australian equivelent of CarQuest is, pick up a remanufactered 14684 (should be about $80 US or less), and you should be good. Then you can bring the old one back for the core credit.

Good luck!

-Matt
402BD
I would agree. A friend nearly lost his RV7A when the alternator fried his P and E mags from 20+ volts and high amps output causing engine stoppage at low altitude after takeoff. Fortunately he managed the impossible turn and got back okay. Alternator repeatedly tested okay. Dynon EMS clearly showed the out of spec voltage and amps when the failure occurred and on some previous flights. Replaced the internal regulator, and the problem went away. After repair of the mags, everything has been fine since.
 
I would agree. A friend nearly lost his RV7A when the alternator fried his P and E mags from 20+ volts and high amps output causing engine stoppage at low altitude after takeoff. Fortunately he managed the impossible turn and got back okay. Alternator repeatedly tested okay. Dynon EMS clearly showed the out of spec voltage and amps when the failure occurred and on some previous flights. Replaced the internal regulator, and the problem went away. After repair of the mags, everything has been fine since.

Glad I have Slick's. Also happy with my decision to use ATO fuses/fuse blocks and toggles. Easy to wire up, easy to fix IF it breaks, reliable, cheap, lightweight.
 
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It continually amazes me that folks continue to install these failure prone alternators just to save a few bucks, I just don't get it :confused:

Especially true for folks that install mega buck panels but fail to see the logic of upgrading the alternator to a higher quality unit to supply the high $$$ glass with a reliable power source.
 
Walt,

I have the Plane Power alternator. Having seen a few "offline" experiences how can I have better.

Money is no option, but what is better?
 
Walt,

I have the Plane Power alternator. Having seen a few "offline" experiences how can I have better.

Money is no option, but what is better?

My personal opinion only, I prefer the B&C with seperate regulator so the electronics can be mounted in the less hostile environment of the cabin, plus I think overall their MTBF is higher than the PP from what I've seen.

I also think its very wise to have a back up power source like the SD8 or SD20 available just in case. I've never had to use mine but its nice knowing its there if I need it.
 
What is the logic in not turning the generator off or on with the engine running? I have been in the habit of not turning on the generator until after engine start and have not had any issues. FYI, I have a fairly simple electrical system and am not using the EXP setup.

Thanks!

The Nippo units are intended for automotive use. They where not designed to have the field energized or de-energized while the motor is running. Some believe this can lead to premature failure.
 
My personal opinion only, I prefer the B&C with seperate regulator so the electronics can be mounted in the less hostile environment of the cabin, plus I think overall their MTBF is higher than the PP from what I've seen.

I also think its very wise to have a back up power source like the SD8 or SD20 available just in case. I've never had to use mine but its nice knowing its there if I need it.

For the record, and for what it is worth, during my troubleshooting of the nuisance tripping of the field circuit I took a heat gun to the PP regulator. The PP regulator continued to operate even after the plastic potting material around the electronics had been melted into a mass of goo.
I am convinced it can operate in the environment.
 
Should have jumped back on the forums a bit earlier and updated you all.....Anyway I removed the Alternator and it was another internal Voltage regulator Failure. I had a previous failure of the same type at about 90 hours and my Auto elec said that the reg that was fitted last time was **** and he was not surprised it had failed. He installed a better quality Reg on this occasion (I think it was a Nippondenso unit) and said that I should make sure there is adequate cooling air going to the alternator as typical auto setups have the Alt installed behind the cooling (not the case in the RV).
He also mentioned that the Volt Regs in these Alternators don't like the Alternator running at low RPM for long periods of time. He suggested not to run below 1000rpm where possible as the lower RPM causes the Field to load up and the VR works harder to manage the load. No doubt someone will come back with an opinion that this is not the case but that's what the AutoElec said so take it with a grain of salt if you like...
I'm now going to install a larger cooling duct directed onto my Alternator and if it fails again I will probably upgrade to something more robust.
I have a back-up battery system so Alt failures don't worry me much other than the inconvenience......and yes (for what its worth) with the benefit of hindsight I would recommend builders don't install cheap Auto/Alternators in the first place...
 
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