Balky Alternator

[@paulschannel3046]

I've had two alt failures. Each one on the way to a fly in. The first was about 100 miles from home when it quit. Landed to check for something obvious such as loose wire or belt failure. Nothing. Flew home with the master switch off using handhelds for navigation and traffic. (I never thought about if I was legal or not). My aircraft is an RV which I built and I have the repairmen cert so I'm the chief of maintenance as well. Once home, because of availability and cost, I swapped the aircraft alternator with one from O-Reilly's aircraft supply. About 100 bucks for a drop in replacement and all was well. Fast forward about two years and on the way to another fly in that one failed. With the help of a guy for transportation and another for a couple tools, I had it fixed. The lessons learned from the first failure were invaluable in dealing with the second. When returning the failed alternator after returning home, they gave me a full refund of the new one because it had a lifetime warranty. I was happy. The first alternator, (aircraft alt) had lasted about 500 hours. The second about 100. Hopefully this one will do better. Even if it doesn't, I LOVE the fact I can get it replaced even on a Sunday nearly anywhere and be on my was in just a few hours. Got to love experimental aviation. Sorry for the long post. Like you said, alt failures seem to never happen at a good time... always away from home.

[@engineerinhickorystripehat]

That's only about 8000 miles . We had better luck with generators way back when

[@robvenom1058]

Oreilly alternators fail because the rpm they are at. Look at the size of the flywheel on your prop then Look at the crank gear on a car engine. They are spinning 2x to 5x there designed operating speed. Only way to get more life is to put a bigger alternator drive on it. I see this happen weekly.

[@JosephHHHo]

For $100, why not mount a cold spare in the plane somewhere?

[@robvenom1058]

@@JosephHHHofrom a mechanics point of view. The work and cost to mount another alternator on an experimental and still have the cowling fit would far exceed the usefulness. Not to mention would need a way to drive it. You could run it off the accessory drive on the rear but would need to order a new accessory drive that fits and then an alternator that would between firewall and engine. If you ran it up front the flywheel would need swapped out for one that has 2 belt grooves and 2 seperate length belts. Best case scenario a competent mechanic could do it for $1000.00 all in. Realistically it's a $2,000 job for fab work, testing, wiring, etc, unless done by the owner. They could carry a spare but with everything aviation you could lose any number of components and trying to carry spare for those would fill the plane and make it unusable. Whenever I have an aircraft with alternator failure we swap alternator and voltage regulator box. I have seen both units effect each other and a bad alternator cause a VR to fail and vice versa. For the cost and time why not swap both.

[@JosephHHHo]

@@robvenom1058 There is no need to have the spare connected. Unless you are crossing an ocean, you can pick just about any public airport to set down, whip out the tool kit and swap it in. Doing the work to tie it in may be counterproductive because the spare would be spinning while not being productive.

[@Centurion54X]

thanks for loading these onto KZbin Mike I'm a first time owner, these seminars and your books have helped me a lot

[@savvyaviation]

Glad you like them!

[@DWBurns]

Long in the tooth is a saying from cowboy lexicon, an older horse will have longer teeth in the back of their mouths in a time before equine dentistry. Also horses long ago were allowed to keep their “wolf teeth” a tooth akin to our “I” teeth. Wolf teeth grow and get long with age, an older horse is long in the tooth. Today, we pull wolf teeth as soon as the vet can get ahold of the tooth. Wolfs teeth will cause pain to the horse with a bit in their mouth. No longer are our horses long in the tooth, it is our alternators now days. Good topic today. I enjoyed the talk. My wife is an A&P and I built a Jeep for a toy. We look at thing like this totally differently. We just bought an Arrow as a project airplane and family toy. I am learning a lot from these talks.

[@TheFirePilot]

@4:10 the tail number is N2638Y this is our plane! Is this a stock photo you found? I’ve never seen this picture before!

[@TheFirePilot]

I was wrong ! His tail number is N 2638X. They are siblings!

[@savvyaviation]

N2638X is Mike's Cessna 310...look closer!

[@jimrankin2583]

As Mike says, overcharge shortens life of the battery from heat buildup but undercharging does as well. In fact, the worst possible result of that is letting a battery discharge fully and stay discharged.

[@axel-stephanesmrgrav7036]

As always, a good presentation illustrating some of the challenges and dilemmas we are faced with as owner-pilots. I never had an alternator fail on me, but I have had two difficult to diagnose issues. The first was ignition related, causing the engine to be very hard to start, one cylinder going cold during ground leaning and exhibiting lean misfire when 50-100° LOP. I ended up discarding the Champion spark plugs with megaOhm resistance, and replace them with Tempest which cured the issue. The second issue was alternator related. The symptoms were somewhat similar to what you describe in your presentation. One alternator had difficulties coming online, and the difficulties seemed to be worse in cold weather and increase with time. It turned out the alternator relay was arcing due to a turned stud. The mechanics I talked to about the high resistance issues, to this day do not know about the issue with the "old-style" Champion plugs although it has been more than ten years since they were diagnosed. Had I not happened to read about it in one of your articles, I would not have thought of testing the resistance. I mean: they did pass the "bomb test". My "alternator" problem was not hard to diagnose once it got so bad that I could reproduce it reliably on the ground...

[@savvyaviation]

Yep, those defective plugs are still out there...

[@jimrankin2583]

Generator brushes and the commutator they run on carry the full output current of the generator. So they’re much larger and the commutator has many more potential failure points between and under the individual segments than the two slip rings and rotor/field winding. The alternator brushes and slip rings carry only the field current. The output current of the alternator passes through the solid state rectifier. When silicon diode technology advanced to the point where the rectifier was reliable, generators quickly became obsolete.

[@kirkrobertson8033]

Hi Mike, your video was really informative and helped me understand my alternator so much better. However, I'm still facing a problem where the alternator goes offline midflight, and cycling the alternator switch is the only solution. It seems to be related to an overvoltage issue causing the regulator to protect the alternator. Despite replacing the alternator, three voltage regulators, and using a Zef Tronics regulator, replacing the master alternator toggle switch the problem persists. I've also checked and cleaned all battery terminals. Any insights or suggestions would be greatly appreciated. Thanks!

[@4395R]

So I had a intermittent alternator (SEL plane), I'd fly and notice from time to time the charge current read zero. I had my mechanic at the time check it and he cleaned the brushes and slip rings as good as possible without removing. Eventually the alt failed in flight, I notified ATC of the situation and immediately received a clearance to land at my destination AP. Hind sight I should have turned off the master, but I kept one radio operating and contacted the tower before I landed from which the battery drained. I had the alt rebuilt ($800), they found a nut bouncing around in there which looked suspiciously like a exhaust manifold nut (I had exhaust work done not long before my problem started) and it shorted and burned out the coils. After installing the alt I quickly found out my battery was only good for one crank, another$400 for a new battery. In the end of I had rebuilt to start with or shut off the master immediately I probably would have saved another $400. Live and learn.

[@Saltlick11]

Is there an easy way to tell if your alternator has enough juice to handle the electrical load? When I lift my gear on T/O, my alternator breaker pops. I reset it and then the gear tucks in, but it feels like the surge from the gear motor at some point in the process overloads the alternator?? Any thoughts?

[@FlyingNDriving]

With all these highly rated shops you flew past, prob worth having a mechanic poke his head in the cowling to see if they can do a multimeter test and see if there's anything obvious that jumps out

[@dannyroosenboom3640]

the voltage produced by an alternator not only depends of the field, but also the rotationspeed of the alternator. so if it produces irregular voltage, it might be that the alternator belt is slipping

[@savvyaviation]

good point.

[@libertine5606]

I would want to run it by a A & P anyway. Maybe, the intermittent problem is a sign of something they have seen before. Since the intermittent problem at some point will become a problem I would keep looking for what it is until it's found. I am not one to throw money at a problem but I don't want to get stuck on a cold ramp as the sun is setting either. The money saved in just waiting for the problem to make itself apparent easily can be eaten up by a taxi ride to a expensive hotel. Working with a mechanic that you don't know. Maybe even having to take a commercial flight while the problem is fixed. All intermittent problems have a a cause and by figuring out what it is and correcting it you know your plane is in top shape all the time. The worse part would be if the unknown cause was a masked sign of something much worse. Maybe a intermittent short under the panel that could cause a fire. Having a fire in a airplane is even worse than having a fire in a boat! To me I need to know what the problems is so that I can understand it and then I know what risk I am taking. Even if it means a little more expense in finding out it really isn't a safety hazard.

[@charlesdonaldson962]

I would recommend never flying the second time after something like that. Without doing that, you know tear down on the alternator and. Put it back together just like you would an engine., If you had a Likely problem that wouldn't reproduce itself.If at alternator locks up, do to a bad bearing or sparks From bearings or other metal cause fire, it's at least not gonna be good. If you talk to generator mechanics and for large I'll tell you when a generator quits producing electricity and I know it's true sometimes bearings Are failing. Brushes and wiring and things could cause a short death affects avionics or again fire. I have experience with the DC motors. Starters alternators etc. So I know how simple it is to Turn down an alternator Or starter. I would just suggest being careful and study first on Necessary knowledge each model might have but probably doesnt, Like you would for anything the first time. good luck!