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Nippondenso alternator issues

MrNomad

MrNomad

Well Known Member
I replaced my Nippondenso alternator (Van's part # 14684) which had 420 hours with a rebuilt/loaner ALT that has zero hours. The old alt would spike to 16.1 volts causing the EMS to alarm. The replacement alt spiked one time in the last 1.5 hours, alarmed briefly, then stayed within the settings set up in the EMS.

Nevertheless, it constantly vacillates between -2 amp and +3 amps even though the load (radios and lights) remains constant.

When the original ALT was new, I never recall an over voltage circumstance. What's your experience with these alternators? Are you experiencing vacillations in voltage and amperage w/o changing the electrical load?

Barry
 
I am pretty sure that is the alternator with no internal voltage regulator (mine is 14184) If your voltage is fluctuating, the first place I would look is the voltage regulator. Do you have an external voltage regulator?
 
Hi Barry,

The 14684 is internally regulated, so no use going off on a wild goose chase looking for a part that isn't there.

I would discount mior amp fluctuations - I don't know what instrumentation you're using, or what it is indicating (amps out of alternator, amps into the bus, amps in to the battery, etc) - but I have never seen one in an airplane that I would trust to read better than =/- 5 amps or so.

Voltage fluctuations tell you more however - one spike here or there when adding or taking off a load is not terribly unusual, but if it is varying a couple of volts on a regular basis, i'd say you have a regulator problem.

Two EMPIRICAL observations after usng these alternators for years on three different airplanes in our fleet and watching countless threads on VAF:

1) Turning the alternator on or off with the engine running is a good way to destroy the regulator (over time)
2) Getting good cooling air to the regulator on the back of the alternator never hurts.

One thing you can always do with an automotive alternator is take it by your favorite auto parts store and have them test it for you - they won't ask any questions if you tell them it is off your beloved Suzuki Samurai.... :)
 
Nippondenso - internally regulated

Thanks Paul.

Yes, u r correct, it is internally regulated. I am using a Dynon D180 to monitor.

The ALT switch is turned on before the engine is started. Yes, I have a blast tube directing cool air to the ALT.

The local parts stores were useless in their diagnosis. Auto Zone couldn't find an adapter to test it and the second shop claimed the original ALT was good even tho it blew the breaker so "free" testing seems to be worth what u pay for it.

I think it's time for a new reg from a more reputable source. Thx.
 
I had similiar issues with that alternator. I was using a B & C regulator because if the alternator stopped outputting, the regulator would activate a warning light. The Van's alternator kept tripping the field circuit breaker. After spending hours trying to diagnose the problem, and talking with B & C technical support, the conclusion was that inexpensive alternators output "dirty" (i.e. "spiky" my words) voltage. I then broke down and purchased a B&C alternator, it has worked flawlessly every since.
 
My ND quit around 220 hours (more or less on schedule per the experiences here). What I recall is that Vans is now selling the Plane Power alternator - which is what I went with and have, so far, had very good experience. I recall having to change the bracket but that it was a pretty easy job.

Dan
 
Barry,

You need a more specific alternator shop than AutoZone for testing and rebuilding -

TAE-Building.jpg


1401 E. 20th St., Tucson, AZ 85719
 
Today mine went off line while on a test flight. When new it was putting out 14.1 volts and in about 20 hours of phase one, its dropped to 13.7 volts. When it went off line today, voltage steadily dropped and at 11.6 volts, I cycled the alternator switch on and off and it came back on line putting out 13.7 volts again. I do have a blast tube on the diodes also.:mad:
 
That was the local firm who pronounced the old ALT OK

Gil:

That was the local firm who pronounced the old ALT good so I stand by my comments that "free tests" should be viewed with concern. Chet & I are thinking of creating a test stand so we can control the entire environment. Unlike auto applications, the flywheel versus ALT pulley is much larger on a Lycoming. My guess is the ALT is spinning at a much faster rate than Suzuki ever imagined. Perhaps that's a factor too.

Barry


az_gila said:
Barry,

You need a more specific alternator shop than AutoZone for testing and rebuilding -

TAE-Building.jpg


1401 E. 20th St., Tucson, AZ 85719
Click to expand...
 
Hey Barry,

For what it is worth, my 1987 Suzuki Samari alternator (55 amp) has been creeping up for the last three flights. Over its life since 2006 it has been steady at 14.1 to 14.3 volts. Last week it was showing a steady 14.5 then this week 14.9. I suspect the internal regulator is loosing it. Good thing is that it was purchased at NAPA with a life time warranty for my "off road" vehicle. I plan on taking it off tomorrow and having it tested.

Cheers,

db
 
don't forget, the battery can have an effect of the voltage. i had high voltage readings and a new battery solved the problem. it was that peskey odyssey 680.
 
HARBOR FREIGHT

Gil, I have one of these. Thx.

NAPA: I didn't consider that source. Lifetime warranty is good idea. In a conversation with a retired alternator rebuilder, he said that over time regulators fail and given the extraordinary rpm we subject these ALTs too, that should also shorten their life.

There appears to be different regulator suppliers. If anyone knows of one brand being better than others, please supply the numbers off your regulator or from your receipt.

The $25 I voluntarily contribute each year for access to this website is worth its weight in gold. Thx all.

Barry



az_gila said:
True, but it can only do that through a high internal resistance. One of these is a good test for that -

http://www.harborfreight.com/100-amp-612v-battery-load-tester-69888.html

image_21950.jpg
Click to expand...
 
I seem to remember someone posting info on a company that made different size pulleys for our ND alternators. If rpm is one of the life limiting issues, a larger pulley and therefore lower rpm's might just give us extra life from these ND alternators. For the money I certainly can't complain about 8 yrs service from my NAPA life time warranty ND.

Anyone remember the post or source??

Cheers,

db
 
Extra rpm

In an auto environment, the SUZUKI alternator pulley versus the crankshaft drive pulley is significantly smaller than the drive pulley on the Lycoming. It stands to reason that increased rotation will shorten bearing and brush life on the ALT. When I asked the retired ALT rebuilder and my local EE they both agreed that the increased revs will attempt to put out more amps exacerbating the burden on the regulator electronics to hold back the alternators propensity to generate energy. Ergo, that shortens the life of the reg (I am not an EE). By installing a larger pulley on the ALT, we reduce the # of revs. The negative is that the ALT may not put out enough amps at engine idle but that's easily addressed by leaving unnecessary electrical burdens until airborne and cranking 2400rpm.

Yes, if a larger alt pulley can be found, please post the supplier. Thx.


db1yg said:
I seem to remember someone posting info on a company that made different size pulleys for our ND alternators. If rpm is one of the life limiting issues, a larger pulley and therefore lower rpm's might just give us extra life from these ND alternators. For the money I certainly can't complain about 8 yrs service from my NAPA life time warranty ND.

Anyone remember the post or source??

Cheers,

db
Click to expand...
 
My latest ND did as described above. Started creeping up and finally died with about 750 hours on it. It worked below 2000 RPM so ground checked and tested OK, but as soon as the rev's went beyond 2K it completely stopped putting out anything.

My plane has right at 2000 hours on it and I'm on my 4th ND. First one lasted over 600 hours, second one almost 600, third one 750. Not bad and just as good as some of the more expensive units.

It sure is nice to be able to walk into any Aircraft Autozone and pick up a free replacement as they have a lifetime warranty.
 
As a data point, my 40a ND worked flawlessly for 1200 hours. I replaced it with a new one when I overhauled the engine, but the old one sits as a spare on the shelf. Two blast tubes, one to the board in the aft end, and the other feeds the body.
 
MrNomad said:
...Yes, if a larger alt pulley can be found, please post the supplier....
Click to expand...

Moroso (drag race stuff) makes large alternator pulleys. Not sure if they service the ND, but I would suspect so.

I went down to the loal hardware store and purchased the size pulley I needed and machined the center hole to fit.
 
The pulley size is a red herring.

http://www.armatureserviceco.com/ShowItem/135035 14684 NIPPONDENSO ALTERNATOR.aspx

This says that the pulley is 2.7" dia, I just measured my PlanePower and it is 2.75" and the engine pulley is 9.75" Close enough to the same. 10,000 rpm is fine for the ND 14684.

The windings are not shorting, the bearings are not failing, the brushes are not eaten up, so, speeds, belt loads, and vibration are not the factors.

Solid state parts seem to be failing, that means combination or singularly, heat and voltage spikes. No cycling, no spikes, so it must be heat, heat, heat.

OK, we left out connector vibration and getting loose, and corrosion of the many connections for that field excitation wire. There could be some electro-chemical-mechanical issues too. :D
 
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Just as an update:

Pulled my 55 amp ND off the 9a and took it down to the local starter/alternator rebuilder (could not find my @#$$XX$@ receipt from NAPA for the life time warranty). He put it on the tester and of course it was solid at 13.8 volts--but clearly at an rpm much lower than what our Lycs generate for the alternator. Since I had gone to the trouble of removing it, I had him replace the regulator and the brushes (which were thin). He also checked the bearings and windings--which were good. Reinstalled on 9db and all is good again and steady at 14.3-14.5 volts. Total cost $63! I recall having my old Mooney 201's alternator rebuilt once---seems like it was over $400.

Cheers,

db
 
The last couple flights I've seen my volts creeping up my ND alternator, so I dropped it off at an alternator shop and the repair cost is higher than a replacement. Question, is there any mods needed to the cooling fan or is it a straight drop in? I'm at work and cant prove the rotation but have read that the alternator spins reverse to an auto setup?? Is it an issue?
 
Over voltage is one of the known failure modes of the intrrnal regulator in that particular ND alternator. A good alternator shop can fix it. There is also a procedure on the Aero electric website how to modify that alternator to use an external regulator.
 
They must have found more than the voltage reg worn as the quote came back at $156, they have a new one for $130. I'm not sure if that is the core return price or outright, comtemplating whch is the better way to go... just pick up this one or pay extra for the Plane Power from Van's for $450....
 
Repair facility in Ohio

I replaced my ALT with a rebuilt from ROCK AUTO. However, the voltage varied too much so I sent my original unit to Mike Lauer in OH for rebuild. He found a worn bearing and also replaced the regulator with THE BEST REG he could find. Apparently, (I'm no expert), but regs vary in quality.

[FONT=&quot][email protected]

[/FONT]Performance Starter
Canton OH 44706
330-456-3019

Tell him u r calling about your airplane and you got this message from Barry in Tucson. His fee was $79.69 including freight back to Tucson. His rebuilt seems to be working fine in my 9A. Confirm he will use the BEST REG.
 
DHRYCAUK said:
The last couple flights I've seen my volts creeping up my ND alternator, so I dropped it off at an alternator shop and the repair cost is higher than a replacement. Question, is there any mods needed to the cooling fan or is it a straight drop in? I'm at work and cant prove the rotation but have read that the alternator spins reverse to an auto setup?? Is it an issue?
Click to expand...

There might be a minor difference in the fan's efficiency when running backward, but not enough to matter. Most of the automotive alternators being run on Lycs are running 'backward'. IIRC, some of the Honda alternators are designed to turn the same direction as an a/c alt.

Charlie
 
If you are looking for the best - and adjustable - regulator check out B&C's LR3. I've been using Bill's LR series regulators for 30 years on multiple homebuilts, and have never had a failure.
 
What is a B&C alternator. I have a Nippondenso alternator. Or rather "Had". I have finished building a 9-A w/ a narrow deck lyc 0-320.. Ran engine and had fuel pump problem. Found out the fuel pump was a high pressure pump. Bypassed mech pump and used elec. fuel pump to run engine. Just as I was shutting down the engine, the alternator started smoking. Found that the stator had shorted out . I would like to replace old alt with a new one. Can you use an auto alternator that puts out 110 amps? Or do you need to stay with a recommended alternator?
 
cknw said:
What is a B&C alternator. I have a Nippondenso alternator. Or rather "Had". I have finished building a 9-A w/ a narrow deck lyc 0-320.. Ran engine and had fuel pump problem. Found out the fuel pump was a high pressure pump. Bypassed mech pump and used elec. fuel pump to run engine. Just as I was shutting down the engine, the alternator started smoking. Found that the stator had shorted out . I would like to replace old alt with a new one. Can you use an auto alternator that puts out 110 amps? Or do you need to stay with a recommended alternator?
Click to expand...

Here is a link to B&C - http://www.bandc.biz/belt-driven-alternators.aspx

They are generally reported to be quite dependable.

One can use an automotive 100 amp alternator, if it will fit, but it will likely be larger and heavier.

disclosure: I have the standard Vans Plane Power brand.
 
That size alt would run almost anything you could put in an RV, including an electric air conditioner. :) Do you really need one that big?

If the one that failed is a 'one wire' alternator (internal regulator), you should be able to replace it with one for a Suzuki Samurai. They're under $100 from many suppliers. I think the Lester number is 14684. It's rated at 55 amps, and will run just about anything that will fit in an RV, short of that air conditioner.

There's a world of controversy about whether using an internally regulated alternator is a good idea, but a lot of people do use one safely and effectively. You do need to research the pluses and minuses, and whichever you choose, you do need some form of overvoltage protection if you have extensive and valuable avionics in the plane.

Or, you can pay half a kilobuck for a 'real aviation alternator' (which is an automotive model with the internal regulator removed) and convince yourself that it's 'better'.

Charlie
 
Another fan of B&C here, I've replaced plenty of failed auto alternators that seem to last a few hundred hours on average.

I've yet to replace a failed B&C.
My personal experience: you generally get what you pay for.
 
B&C are premium quality alternators. If you ever let the smoke out of one, chances are good they'll repair or exchange it for an overhauled one fairly inexpensively.

ETA: The initial purchase price of a B&C alternator is not an inexpensive thing however, it's one of those " buy once cry once" things... I've got a buddy with a Lancair 360 with dual electronic ignition systems ( not a very friendly aircraft to have a forced off-airport landing in) and a bunch of electronics in the panel which he flies a lot of IFR and over inhospitable terrain who recently had a forced landing, fortunately at an airport. It didn't take much convincing for him to upgrade to a B&C alternator and a big Concorde sealed RG battery when he got his new engine installed.
 
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Some short points on using industrial and small (relatively) auto alternators in aircraft. I copy and paste a thread I archived with a friend of mine who is a retired engineer for one (if not "the") top belt mfg's.

I'm a Technical Counselor for the Experimental Aircraft Assn. I was inspecting a RV-7A and noticed that the builder had installed an aftermarket 40A Honda Generator. It had a 2-1/4" Alt pulley and was driven by an 11" pulley on the Starter ring gear.

Some quick math showed that the alternator was overdriven to the point that during take-off RPM (2700) the Alt was spinning above 12800 RPM. The output curve for the alternator "flat lines" at about 6400. The belt speed in Feet Per Minute (FPM) at 2700 engine RPM is 7775. The builder is using an automotive application who's rated top FPM is 6500.

The "moral" for my post is check the output curve, don't run it faster than necessary and don't exceed the rated belt FPM. Oh, the logic behind not running faster than necessary is that idle rpm is always sufficient to keep the Alt in the "output" mode - but it should be checked when you're "adapting" an auto unit to aircraft.

mjb
 
Alternator Rotation

The specs on the NipponDenso #14684 alternator show a clockwise rotation which is apparently due to the internal cooling fans. The rotation is counter clockwise on the RV,s. Could this be a factor for premature failures? I have never seen this brought up on the forum.
 
Virtually all automotive alternators (except some Hondas) are the same. I'd bet that the $500 'aircraft' automotive models have the same fans. The fans still move air (I've had an alternator shop spin one up on their test rig). Of course, if you don't supply cool air for the fans to move....

Charlie
 
jlprice said:
The specs on the NipponDenso #14684 alternator show a clockwise rotation which is apparently due to the internal cooling fans. The rotation is counter clockwise on the RV,s. Could this be a factor for premature failures? I have never seen this brought up on the forum.
Click to expand...

This has been discussed many times over the years. There are hundreds of RVs using ND alternators that are rotating the "wrong way". Matter of fact, the 35a alternators Vans shipped for many years had the fan removed. I've used the same alternator, sometimes with fan the "wrong way" and sometimes with no fan for the past 15 years on my RV-6. It is always good to install a blast tube to the diode end of the alternator.
 
Charlie, I'm thinking the blades on these internal fans are pitched for CW rotation and produces more efficient airflow for that direction.

Jim
 
Sam...... I just read your reply to my post. Your point is well taken. My alternator problem just occurred and am investigating the alternatives and in a learning curve on this.
Jim
 
Denso Alternator Update

An update from my last post on 04/08/14: I had no further issues until yesterday. The alternator totally failed during a 3.8 hour cross country flight while the high dollar electronic panel drained the life from 2 PC-680 Odyssey batteries getting back home. Nothing obvious externally on the alternator, connections all good, spun freely and noise free. Removed and tested at Advance Auto. It would not pass the internal "ground" test. I know some people here have had VERY good luck with these alternators but for me, it was "penny wise and dollar foolish". I had a blast tube on the regulator, never flew through rain, spent money for a B&C OV kit, and got under 100 hours of use from it. Will replace with a B&C alternator with external voltage regulator.
 
9GT said:
An update from my last post on 04/08/14: I had no further issues until yesterday. The alternator totally failed during a 3.8 hour cross country flight while the high dollar electronic panel drained the life from 2 PC-680 Odyssey batteries getting back home. Nothing obvious externally on the alternator, connections all good, spun freely and noise free. Removed and tested at Advance Auto. It would not pass the internal "ground" test. I know some people here have had VERY good luck with these alternators but for me, it was "penny wise and dollar foolish". I had a blast tube on the regulator, never flew through rain, spent money for a B&C OV kit, and got under 100 hours of use from it. Will replace with a B&C alternator with external voltage regulator.
Click to expand...

When you do the autopsy can you tell us which component failed? Diode array, or regulator, or physical connection wire? B&C says they build with new components etc. Just wondering what exactly failed. Thanks for sharing . . .!
 
9GT said:
An update from my last post on 04/08/14: I had no further issues until yesterday. The alternator totally failed during a 3.8 hour cross country flight while the high dollar electronic panel drained the life from 2 PC-680 Odyssey batteries getting back home. Nothing obvious externally on the alternator, connections all good, spun freely and noise free. Removed and tested at Advance Auto. It would not pass the internal "ground" test. I know some people here have had VERY good luck with these alternators but for me, it was "penny wise and dollar foolish". I had a blast tube on the regulator, never flew through rain, spent money for a B&C OV kit, and got under 100 hours of use from it. Will replace with a B&C alternator with external voltage regulator.
Click to expand...

You'll be very happy with a new B&C unit.

FYI, though, ND alternators can be easily modified to be externally regulated by a B&C (or other) regulator.
 
9GT said:
An update from my last post on 04/08/14: I had no further issues until yesterday. The alternator totally failed during a 3.8 hour cross country flight while the high dollar electronic panel drained the life from 2 PC-680 Odyssey batteries getting back home. Nothing obvious externally on the alternator, connections all good, spun freely and noise free. Removed and tested at Advance Auto. It would not pass the internal "ground" test. I know some people here have had VERY good luck with these alternators but for me, it was "penny wise and dollar foolish". I had a blast tube on the regulator, never flew through rain, spent money for a B&C OV kit, and got under 100 hours of use from it. Will replace with a B&C alternator with external voltage regulator.
Click to expand...

My autozone alternator has a lifetime warranty. So while an alternator failure is never fun, the cost would be just my time to replace the unit. Now if the batteries are damaged by the failed alternator, that could certainly get expensive.
 
WingsOnWheels said:
My autozone alternator has a lifetime warranty. So while an alternator failure is never fun, the cost would be just my time to replace the unit. Now if the batteries are damaged by the failed alternator, that could certainly get expensive.
Click to expand...

External component protection should be external to the alternator, anyway. If OV protection is installed, you'd need an alternator failure, for that failure to be an OV failure (instead of just dying, which is much more common), and for the OV protection circuit to fail at the same time.
 
OVP

I agree, an external current input to the alternator (field) is the way to go. One of the best places to put a OVP (over voltage protection) circuit. Not sure how you would shut down an internal regulator circuit ( unless it had a OVP built in ).
The best alternators I've used is the B&C, even there little 8 amp version. Ran one of these for years with no maintenance. Simple design too. The worst has been the Chrysler types in Cherokees, bad mounting, short life, you name it.
John
 
There's an OVP circuit in the aeroelectric connection book using a standard master relay in series with the B lead, controled by his OVP module. Not as 'elegant' as the B&C alt/reg setup, but an order of magnitude less expensive. It's under the radar in the book now, because pilots were treating the system like a traditional a/c charging system (needlessly load dumping a functioning alt in flight), killing the alt.
 
rv7charlie said:
There's an OVP circuit in the aeroelectric connection book using a standard master relay in series with the B lead, controled by his OVP module. Not as 'elegant' as the B&C alt/reg setup, but an order of magnitude less expensive. It's under the radar in the book now, because pilots were treating the system like a traditional a/c charging system (needlessly load dumping a functioning alt in flight), killing the alt.
Click to expand...

This is pretty much how mine is set up. In the event of an OV the relay opens the b-lead connection. I have seen diode failures kill batteries in cars. Batteries dont like AC very much.
 
DENSO alternators are pretty easy to work on. You should check the brushes before trashing it. Could be a $6 fix...
 
BillL said:
When you do the autopsy can you tell us which component failed? Diode array, or regulator, or physical connection wire? B&C says they build with new components etc. Just wondering what exactly failed. Thanks for sharing . . .!
Click to expand...

I took the back off, removed the brushes and it all looked fine to me. I really don't know how to test the diodes or other parts of the alternator. I purchased a slightly used B&C 60 amp alternator and voltage regulator from a forum member and installed it last weekend. All is well now.
 
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