JonJay

JonJay

Well Known Member
There are plenty of old threads, and not so old threads, about alternator failures, but I chose not to tack onto them. I added this for another data point.
Standard Van's 60A (Suzuki Samari, Nippo Denso i.e. and a hundred other similar rebuilt automotive product.)

This is my second failure. The first failed early, around 20 hours, I assumed due to turning on the field after start up. My second gave up the ghost yesterday at 350 hours. I religiously turn on bat and alt before start up.

I landed, went to the auto store, they tested the unit, bad regulator, sold me a new one with a "life time" warranty for $100, installed, tested, back in action. I landed at 4:00, cowling off, alternator removed, and was at the auto parts store at 5:00, back home, on the ship, test ran, and done by 6:00.

I do believe the Plane Power units are better engineered, but they are not problem free according to the posts I have seen. If I had a PP unit laying around, I might have changed to it, but the simplicity of finding the part at virtually any auto parts store led me back to keeping with the standard part.
 
Do you shut the alternator/master off before pulling the mixture? Definitely a no-no if you want long alternator life.
 
One question Jon (for a full picture) - blast cooling directly on the Regulator or not?

I agree on being able to pick one up anywhere - very nice!
 
jon,

wondering which store gave you a life time warranty? some stores are not giving life time. i have a spare alternator on hand at all times and run with a one inch blast tube hitting the regulator. one of my problems was it would check out ok at the store but the ic diode would not act up till warmed up in flight. by mentioning this to the store my replacement was processed. depends on sales person some times.
 
thanks mel........

my auto zone one was bought in CA visiting rosie. it turned out a loose connection was the problem at that time. i hate those electrical problems.
 
LIFE TIME WARRANTY

Advanced Auto Parts has life time warranty too. I think there were once 'Western Auto' in the old days.

I turn on my alternator after start up. Guess that is wrong but on the start up procedure card that way by the previous owner.
 
Blast tube aimed at regulator cooling fins.

Ironflight said:
One question Jon (for a full picture) - blast cooling directly on the Regulator or not?

I agree on being able to pick one up anywhere - very nice!
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That's where it is aimed. You still get a lot of radiated heat off of the cross over exhaust. It is only about four inches away from the back of the Alternator. Perhaps a shield there might help.

Shuck's O'Riely = Lifetime Warranty
 
External regulator

It seems adding an external regulator would eliminate the most common point of failure on these automotive alternators. I believe you can bypass the internal regulator of a normal ND alternator when using an external reg like the B&C unit or even an old fashioned Delco Remy buzz box.

This probably mitigates the need for a blast tube as well.

M
 
JonJay said:
This is my second failure. The first failed early, around 20 hours, I assumed due to turning on the field after start up. My second gave up the ghost yesterday at 350 hours. I religiously turn on bat and alt before start up.

I landed, went to the auto store, they tested the unit, bad regulator, sold me a new one with a "life time" warranty for $100, installed, tested, back in action. I landed at 4:00, cowling off, alternator removed, and was at the auto parts store at 5:00, back home, on the ship, test ran, and done by 6:00.
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Sounds like fun :confused:

I chose option #2, install a quality unit with a proven track record and forget about finding a ride to the autoshop to cash in on my "Lifetime warranty" when I'm halfway across the country :eek:

(hint = B&C)
 
Walt said:
Sounds like fun :confused:

I chose option #2, install a quality unit with a proven track record and forget about finding a ride to the autoshop to cash in on my "Lifetime warranty" when I'm halfway across the country :eek:

(hint = B&C)
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Valid point - especially if IFR usage is in the cards.
 
So how should this be done, switch alt on before crancking the engine or after? Turning it off before or after cut the mixture?

Thank you
 
Moura said:
So how should this be done, switch alt on before crancking the engine or after? Turning it off before or after cut the mixture?
Thank you
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Turn on BEFORE starting. Turn off AFTER engine is stopped.
Just like your car.
In other words, don't turn the alt on or off with the engine running.
 
Heat Shield Required with Crossover Exhaust?

The internal regulator is an electronic part. As we all know, electronics and heat don't play well together, especially over a period of time. Now the internal regulators in automotive alternators do have a pretty good heat sink protecting the electronics, and I'm sure it works very well for a long time in installations for which it was intended.

I have a Plane Power 60A alternator on my RV-7 that I'm just finishing up. I am now installing the blast tube, and I plan to install a heat shield on the crossover pipe of the exhaust, which runs only a few inches behind the regulator heat sink on the back of the alternator. I think the blast tube alone is sufficient enough during flight, or any time the prop is turning for that matter. But after shutdown that crossover pipe is radiating a lot of heat directly on the back of the alternator. If you look at the pipe through an infrared camera after shutdown, it glows like a light bulb.

Edit: I just measured the distance between the crossover tube (that runs between cylinders 1 an 2) and the back of the alternator, and it's only 2 inches.:eek:

In my opinion, it's only a matter of time (or more appropriately, cycles) before the alternator fails if you have a crossover exhaust system without a heat shield giving some protection to the alternator. How much time may vary greatly from installation to installation. The electronics just can't tolerate that much heat.

Disclaimer: Opinion only. Purely speculation on my part. No hard science. I'm not even flying yet. Worth at least $.02.

I am sure there others out there that don't have a heat shield on the crossover pipe, and haven't had any problems. Good for them, but I'm still installing a heat shield (and a blast tube).:)
 
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airguy said:
Valid point - especially if IFR usage is in the cards.
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While buying a quality unit is a great idea, remember that with one or two statistical outliers as an exception, EVERY alternator is going to fail at some point. Design your procedures and system around this, and if you are going to fly IFR, answer the question "what's your backup plan". I would never rely on "it won't fail" as a plan.....

And once you have gone that direction, then the alternator choice is not quite such a big deal. I am fairly convinced that most ND alternator failures come down to poor alignment or poor cooling (or poor initial rebuild quality - pay for a good one). I have over 900 hours on th current one in the Val - working fine! (Will probably die tomorrow....)

Paul
 
Check with B&C....

Mel said:
Turn on BEFORE starting. Turn off AFTER engine is stopped.
Just like your car.
In other words, don't turn the alt on or off with the engine running.
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I'm no alternator expert, but recently spent a number of flights trying to diagnose an intermittent alternator issue. I have a 10 year old B&C 40 amp alternator. B&C provided extensive help in debugging. I spoke with them at length regarding the use of a switched field wire. I was assured that there was no need for such a switch, but that I could not hurt their alternator by turning on or off the switch while running or not. I can't confirm their assertion, but certainly defer to their expertise.

In my case, they told me the field wire or its connector was probably to blame. I could do no test to confirm this, but after several frustrating sessions, I replaced the wire and connector. I've made about 10 flights since and everything has been working perfectly.

Good luck,

Dean Pichon
 
Sparky said:
I am now installing the blast tube, and I plan to install a heat shield on the crossover pipe of the exhaust, which runs only a few inches behind the regulator heat sink on the back of the alternator. I think the blast tube alone is sufficient enough during flight, or any time the prop is turning for that matter. But after shutdown that crossover
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I have one of these Van's heat shields installed on the cross over near the alternator and a blast tube on the main alternator body. I have the Nippo that came with the engine from AeroSport Power. Almost 500 hours and no issues [knock on wood].
 
Alternator Failure?

JonJay said:
.
Standard Van's 60A .
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I have 612 hours on my "standard Van's 60A". It has never missed a beat! It may go on the fritz tomorrow but, I NEVER turn it on until the engine is running and I ALWAYS turn it off before pulling the mixture off. I do have a blast tube cooling the regulator section. So........... Go figure!!?? I think alternators are like any other piece of electronic equipment, heat being the main enemy.
 
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Strike Three and your outa here!

Heading to Van's to pick up a Plane Power after my 3rd Nippo Failure. This one lasted about 60 hours. Regulator failure, again.

I intend to install the heat shield on the cross over.
 
foka4 said:
It seems adding an external regulator would eliminate the most common point of failure on these automotive alternators. I believe you can bypass the internal regulator of a normal ND alternator when using an external reg like the B&C unit or even an old fashioned Delco Remy buzz box.

This probably mitigates the need for a blast tube as well.

M
Click to expand...

A solid-state regulator intended as a replacement from a 1970's Ford vehicle also works great with a ND Alternator that's been modified to not employ its internal regulator. Simple 3 wires to hook up, and if you want to add an idiot light, there's a 4th terminal on the regulator already for that.

I'd still recommend a blast tube to help cool the rectifier diodes inside the alternator and if the exhaust crossover is very close to the alternator, some kind of a heat shield sure wouldn't hurt since the diodes can still be damaged by excessive heat.

EDIT: On the subject of the alternator field switch/breaker ops, and engine startup/shutdown.... I just leave the alt field toggle breaker on all the time, and consider it to be an emergency shutoff only in case it's ever needed to remove juice from the alternator field. I've seen too many fried ND internal regulators due to the field being turned on/off while the engine is already running and the alternator spinning. We have a Plane Power alternator in the RV-8, and even though PP says it's ok to power up/down the field circuit while running, I still think its got to be hard on the electronic regulator.
 
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Voice of experience

First,
I dare say there is another RV'er with more alternator experience than me. With 3500 RV hours, and a third of those traveling in packs of 12 RV's bee booping around the country, my combined time with these things is massive.

Next,
I have clear and convincing evidence that the type of installation nor the alternator type, has much bearing on its life. Plane Power, Densos et all seem to fail at the same relative rates. Some at 50 hours, some 200, some last 800, few longer. They will fail.

Blast tubes. If you never fly in rain, blast tubes are good. If you fly in heavy rain, your chances of frying it go way up. We have lost several this way. Hard rain + blast tubes ~= in flight failures.

For anyone who leaves homebase often, there is no substitute for field serviceability. When it fails, and I have never had one on my dozen personal failures at home, how will you get a replacement? I have travelled for years with my autozone receipt and my last 6 or so have been bring in old, get new lifetime replacements. No questions asked. No $ exchanged. Just replaced my last one a couple weeks ago. I also keep a spare in my hanger and travel with it for me and the team. Someone will loose their alternator. I cant afford to have a plane down for a performance if I can help it. I find spark plugs to be more reliable than alternators.

My 2 cents.
 
I agree with Neal's EDIT response; my alterantor field is wired through a separate switch that I leave on all the time. What is the purpose of turning it off after shutdown and turning it on before startup? The checklist is pretty long already...
 
Neal@F14 said:
A solid-state regulator intended as a replacement from a 1970's Ford vehicle also works great with a ND Alternator that's been modified to not employ its internal regulator. Simple 3 wires to hook up, and if you want to add an idiot light, there's a 4th terminal on the regulator already for that.

I'd still recommend a blast tube to help cool the rectifier diodes inside the alternator and if the exhaust crossover is very close to the alternator, some kind of a heat shield sure wouldn't hurt since the diodes can still be damaged by excessive heat.

EDIT: On the subject of the alternator field switch/breaker ops, and engine startup/shutdown.... I just leave the alt field toggle breaker on all the time, and consider it to be an emergency shutoff only in case it's ever needed to remove juice from the alternator field. I've seen too many fried ND internal regulators due to the field being turned on/off while the engine is already running and the alternator spinning. We have a Plane Power alternator in the RV-8, and even though PP says it's ok to power up/down the field circuit while running, I still think its got to be hard on the electronic regulator.
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Can someone explain to me why switching on the regulator when the alternator is spinning is hard on the regulator? It makes no sense. All the regulator does is supply current to the rotor windings, current which is at its highest value when the rotor isn't turning and the battery voltage is lower than the set point. Rotor turning or not it's going to do the same thing, and switching it on at any given time makes it either supply current, or not supply current. I maintain the belief that turning on an alternator while it's spinning stresses regulators is strictly anecdotal and has no electrical basis at all.


Mark Olson RV-7A F1-EVO Rocket
 
Kahuna said:
For anyone who leaves homebase often, there is no substitute for field serviceability. When it fails, and I have never had one on my dozen personal failures at home, how will you get a replacement? I have travelled for years with my autozone receipt and my last 6 or so have been bring in old, get new lifetime replacements. No questions asked. No $ exchanged. Just replaced my last one a couple weeks ago. I also keep a spare in my hanger and travel with it for me and the team. Someone will loose their alternator.
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I also travel with a spare alternator on long trips.
 
I installed the Nippo Denso from Van's 2 times in the 1st 120 hrs with 2 failures.

I am not terribly slow to learn so on the 3rd install, I went with the
high priced B & C 60A alternator and now have 1100 hrs on the plane. No worries.

When it does fail, a charged battery will get me home.
Then I will replace it with another high priced B & C alternator.
 
I have a B&C alternator and their regulator mounted on the firewall. Maybe that is one reason they seem to keep on working. They even recommend installing the regulator on the panel side of the firewall which I didn't do but maybe should have. I figure it can stand as much heat as the battery surely.
I do have a crossover exhaust so another reason having a separate regulator may be good. I have a blast tube pointed at the alternator too. Time will tell. :)
 
Paul said:
I am not terribly slow to learn so on the 3rd install, I went with the high priced B & C 60A alternator and now have 1100 hrs on the plane. No worries.

When it does fail, a charged battery will get me home.
Then I will replace it with another high priced B & C alternator.
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I installed the B&C from the start and have had 0 problems. Others that I know that have the B&C have had the same experience.

Seems like a no brainer to me:D
 
Can someone explain to me why switching on the regulator when the alternator is spinning is hard on the regulator?
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Cribbed from my post to another thread:
Having an internally regulated automotive alternator spinning at speed, then switching it on (the field input on this type of alternator just turns on the regulator) results in a large voltage / current spike that the output diodes have to deal with. I have the Delco SI type internal regulator schematic, and the regulator sense circuit control speed is limited by loop filtering / slope integration. The field control does not have filtering. Switching this type of regulator on via the "field" control input will result in full current instantly, followed by a ramp down to the correct output voltage. It simply wasn't designed to be switched on at speed.

Some alternators have output diodes robust enough to deal with this spike and not suffer reliability issues. From personal experience I can tell you that some Delco 10SI units do not. This type of regulator - alternator circuit is designed to be switched on with the starter, and start producing current from the first revolution. This results in an intrinsic soft start, as the output at starter rpm is minimal.

The regulator IC can suffer from the field current surge as well (I'm told), though I have not personally experienced this failure mode.

If I was designing a regulator for aircraft use, I would ensure that the regulator circuit could not be switched on in a way that resulted in an initial full field output prior to ramping down to the correct voltage. I'd also specify over rated diodes for the alternator, all for the sake of reliability. One hopes B&C and P.P. have done this.

Some of the latest automotive alternators sense the alternator rpm, keep it off line until a certain rpm is reached (reduces the load on the starter), then soft starts the alternator automatically. There are even schemes where the ECU controls the alternator via a serial bus. Perhaps the Vertical Power team will look into that. :D
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Ted Johns said:
Cribbed from my post to another thread:
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Again, how does the regulator "know" if the engine is running or not? It's going to put full current to the rotor until it sees the battery voltage approach the set point, and it will supply full current whether the alternator is spinning or not. The diodes see a "spike", no matter when the alternator is energized, because the battery has just been somewhat discharged because of starting the engine. But the diodes are not the regulator.
 
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In another thread there there was a conversation about the alternator getting quite hot when charging the battery with the alternator switch turned on while on the ground with the engine not running. Having a new plane and learning two EFIS screens I am in the plane with the master on and both EFIS's running quite a bit right now. I leave the battery tender on so as not to run the battery down while I'm working with the screens. Having an alternator switch lets me turn off the field wire so the alternator does not heat up. I can't see any other reason for even having an alternator switch. I don't know if this is even an issue with the B&C setup I have either. You can always pull the breaker of fuse if you have an alternator runaway.
 
molson309 said:
Again, how does the regulator "know" if the engine is running or not? It's going to put full current to the rotor until it sees the battery voltage approach the set point, and it will supply full current whether the alternator is spinning or not. The diodes see a "spike", no matter when the alternator is energized, because the battery has just been somewhat discharged because of starting the engine. But the diodes are not the regulator.
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Would be interesting to watch the field output terminal on the regulator with a recording oscilloscope while switching on/off the feed power to the regulator. I could envision a large transient spike when the field is abruptly shut down and the magnetic field collapses while the alternator is spinning at normal speed.

Anecdotal for sure... but I personally know of 4 ND alternator/internal regulator failures across three different aircraft (twice on one plane) that happened in short order when the pilots were following the practice of toggling the alt field switch while the engine was running. Two of the pilots ceased the practice of switching the alternator on/off and just leave it on all the time, and have not had another failure in years. The other pilot did the external regulator mod on his ND alternator, and uses a Ford-type external solid state regulator and has suffered no more failures and still keeps switching the alt field on/off as he always has.

Incidentally, there is an internal schematic of an ND alternator on page 6 thru 8 of this PDF file: http://www.autoshop101.com/forms/h8.pdf

It shows one leg of the stator coil connected directly to "Terminal P" of the "Monolithic Integrated Circuit" inside the regulator module. Looks like a golden opportunity for a large transient voltage spike on that line (which is directly connected to an inductor) to fry whatever is inside that "MIC" chip.
 
Neal@F14 said:
Anecdotal for sure... but I personally know of 4 ND alternator/internal regulator failures across three different aircraft (twice on one plane) that happened in short order when the pilots were following the practice of toggling the alt field switch while the engine was running. Two of the pilots ceased the practice of switching the alternator on/off and just leave it on all the time, and have not had another failure in years. The other pilot did the external regulator mod on his ND alternator, and uses a Ford-type external solid state regulator and has suffered no more failures and still keeps switching the alt field on/off as he always has.
.
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We have found the same to be true. ND's have been shown to fail quickly with the use of the field switch when running.
Our procedure is to always have the field on during startup and shutdown. Since their primary use case would have it in this mode(in cars), we should follow suit and not reinvent the wheel, nor try and prove why or why not unless we are of the electrical engineer type who just has to know for their own edification. I consider this use of the alt field switch to be proven and debate over.
 
Kahuna said:
We have found the same to be true. ND's have been shown to fail quickly with the use of the field switch when running.
Our procedure is to always have the field on during startup and shutdown. Since their primary use case would have it in this mode(in cars), we should follow suit and not reinvent the wheel, nor try and prove why or why not unless we are of the electrical engineer type who just has to know for their own edification. I consider this use of the alt field switch to be proven and debate over.
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This is my procedure as well and has been since my first of three failures. I believe the first failure was my lack of understanding of this. My second failure and now the premature third failure are due to something else.
I have not checked yet, but does anybody know if the belt that is on the airplane for the ND is the same as the PP? I hope I dont have to take off my prop!
 
Kahuna said:
We have found the same to be true. ND's have been shown to fail quickly with the use of the field switch when running.
Our procedure is to always have the field on during startup and shutdown. Since their primary use case would have it in this mode(in cars), we should follow suit and not reinvent the wheel, nor try and prove why or why not unless we are of the electrical engineer type who just has to know for their own edification. I consider this use of the alt field switch to be proven and debate over.
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I concur. I failed my original el cheapo alternator (35 amp, external regulator) when I tried to charge a dead battery (~500 hours). The second identical unit is still running 650 hours later. I do not have an alternator field switch.
 
Sam Buchanan said:
I concur. I failed my original el cheapo alternator (35 amp, external regulator) when I tried to charge a dead battery (~500 hours). The second identical unit is still running 650 hours later. I do not have an alternator field switch.
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This problem relates to internally regulated alternators, not those with external regulators. I do not believe external regulated alternators suffer the same operational issues. I have an SD8 and external regulator on my Bucker and turn on the alt field after start up and before shut down with no problem or concern and have done so forever on other aircraft with no issues...
 
molson309 said:
Again, how does the regulator "know" if the engine is running or not? It's going to put full current to the rotor until it sees the battery voltage approach the set point, and it will supply full current whether the alternator is spinning or not. The diodes see a "spike", no matter when the alternator is energized, because the battery has just been somewhat discharged because of starting the engine. But the diodes are not the regulator.
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Your analysis is incorrect. :)
The regulator doesn't "know" if the alternator is spinning. But if the field is getting full current as the alternator starts spinning, the output current ramps up slowly (as slowly as the rpm increases). This is very slow by electronic process standards. No "spikes" occur in this scenario.

If the alternator is at speed when the regulator is switched on it puts out all the current it is capable of, instantaneously. As I mentioned earlier, there is no filtering on the regulator enable input, so the output dI/dT is quite large.
 
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