Plane Power alternator service/replacement

Katamarino

Katamarino

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Katamarino
The Plane Power AL24-F60C on my 182 has 1,271 hours, and just over 10 years, since being installed new. Having seen guidance online (everything on the internet is true) suggesting 500 hourly overhauls for alternators, I reached out to some rebuild shops but was informed that these units cannot be overhauled by third parties.

Buying a new one every 500 hours is impractical, so are these units designed to last much longer without needing service? Should I be replacing it given its age and hours? I may soon be in locations where a replacement would not be trivial, so prefer not to run to failure.

I've contacted Hartzell to ask of course, but would be interested in real-world experience.
 
Plane power recommends a brush inspection every 500 hours. That's a long ways from an overhaul.
 
Last month I bought a overhauled 24V 60 amp Ford style alternator for $550. bucks from Aerotech of Louisville. Had to have a good core.
3.5 years ago it was $300. for the same alternator...
 
Gosh am I needing to replace this stuff soon, the replace list is never ending, I’ve put a lot of hours on my airplane in recent years. 500hrs isn’t much. Let’s make this stuff last longer.
 
Stuff = The aircraft? The pilot?
 
mandm said:
Gosh am I needing to replace this stuff soon, the replace list is never ending, I’ve put a lot of hours on my airplane in recent years. 500hrs isn’t much. Let’s make this stuff last longer.
Click to expand...
A small fortune in brushless alternator STCs awaits!
 
mandm said:
Gosh am I needing to replace this stuff soon, the replace list is never ending, I’ve put a lot of hours on my airplane in recent years. 500hrs isn’t much. Let’s make this stuff last longer.
Click to expand...
Flying is expensive and always will be. The risks introduced by running things to failure are too great. And yet, many owners are doing just that.

AT 500 hours the alternator brushes need checking. They will be about 40% gone at that point, and at the next 500 they will need replacing. In airplanes with more electrical demand (glass panels and so on) those brushes will be shot sooner.

The alternators in your car and airplane are both driven at ratios that see the alternator reach redline at the same time as the engine reaches redline. But in the car, your engine is at maybe 30% of redline when cruising, so the alternator is too. In you airplane, you are cruising at around 93% of redline, and so your alternator is doing that too, so the friction of the brushes on the slip rings is much greater and they wear out far sooner.

If that brush check is done when the manufacturer recommends it (500 hours or so), the brushes can be replaced and that alternator will run for another 500, and likely 1000 or more before the brushes fail. But if they fail, their springs will chew up the slip rings, and now you are buying a new alternator ($500+) instead of new brushes ($50 or so now maybe?).

This applies to the vacuum pump and magnetos as well. Buy vacuum pumps that have a provision for checking the vane wear, and you can run that thing to limits without fear of failure. You get the most out of it without it grenading and sending carbon debris back into the instrument system. Tempest and Rapco have vane wear checking ports. Magnetos need 500-hour care, or else they fail or start to act up; at the very least, their spark becomes weak and the fuel mileage falls off and the engine starts shaking some.

Airplanes aren't cars. They don't have the car's super-low-maintenance engineering yet and might never get it. All the fancy stuff in your car that makes it run perfectly for a long time didn't have to be certified by the FAA. If it did, you couldn't afford the car.

Edit: Alternators can last though several engines if those brushes are looked after. I did that.
 
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Alternator in my Lance had a bit over 800 hours on it when it failed due to worn brushes. Brush fell out and dug a groove in the commutator. I didn't know enough to ask, and my mechanic assumed they had been changed at 500hrs (before I bought the plane). Expensive lesson.
 
Long alternator story...
Back in June 2024 I did some work on the engine. One of those tasks was a fresh crankshaft seal. So naturally I had the alternator loose to get the belt off. The alternator and belt was 3.5 years old with 489 hrs on both. I got lazy and thought I am going to put the alternator 500 hr brush inspection off for a little while longer. The alternator is sealed with safety wire so I didn't want to open it myself. I figured I'd take it off next time I am into the engine and take it down to Aerotech for an inspection one day soon. Well one day soon was accurate. I did put a new 85 dollar belt on.

About 15 hrs later I am flying across town to pick up my buddy after he dropped off his arrow for avionics work at Sportys. On the way over there I smell burning rubber. Then I notice the voltage light on. Land no problem 6-10 minutes later. I look and the new belt is off and destroyed. **** the alternator is locked up. WTH!

We cut the belt off and my very experienced buddy says lets just fly it back with everything off and we will stay very low and up north out of the mode C. Atc won't know who it is. We do, plenty of power to start it and off we go with no radios and no power on. Master off. My battery backed upped G5 were useless with no magnetometer I guess? Nav was no problem and we both knew where to fly since we have done it hundreds of times before. Used the compass some but mostly by site.

Now the crazy part was when I went to land on our 2800' airport it was all wrong. The site picture, the speed everything was wrong. I went around and my brain was confused. I am with a 25000 hr CFII and I had a false sense of security. He said several times leave the power off during the flight.
Second time around the pattern I am too fast again and go around. I start to panic a little and said to him you land it. I stay with it and the third time I get it on the ground and stop. Then it hit's me well hell no electric flaps with no power. I don't think it hit him either as he has a johnson bar in his planes. I was disoriented because my G5s were not working and my brain was not using the analog instruments in my panel. Lesson learned. I had everything I needed even with no power. I could have flipped on the master for the flaps and the avionics switch would been off so the transponder wouldn't come on.

So get back into the hangar on 90+° day. I call Aerotech at 11:15 am on a Friday. They have a overhauled unit in stock!
25 minutes later I have it off the plane as my tools were still laying on the table next to the plane. Off I go in my truck to Louisville Ky on a Friday afternoon. I get there and in 2 minutes they have it apart show me the trashed front bearing. I asked how the brushes were and he said it was the first thing he checked and they "fine".
Thinking back I did tighten that new belt pretty tight thinking it was going to stretch a little being new. Bottom line I think I tighten it too tight. Have done it a hundred times on car and trucks. I screwed myself this time.
Drove back through plenty of traffic. Went back to the hangar and installed the new alternator with a used belt. We were going to fly that night and play around with some grass landings but I was too tired after a 95° day. It took 25 minutes to take it off and an hour plus .2 to put back on.
So now I have a fresh alternator but a used belt! lol I have another new 85 dollar belt laying there now but I haven't put it on yet.
That's my alternator story. I did it like everyone else, wait until it breaks then you got to act fast!

Aerotech owner came out to speak with me for a moment and said vibration or belt being too tight would cause the bearing to fail. He did not charge me for the front destroyed case and I thought that was very nice of him. Even though his overhauled alternator cost a lot more now than it did 3.5 years ago. Glad to have them so close. 504 hrs on this one.
IMG_4587.JPG
 
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An issue with Belt replacement on Lycomings is the prop must come off

to do so. This can make the task far more complex; particularly with

some Constant Speed. It is a task that requires an A & P to sign off.

We used 172’s for banner towing and would switch to seaplane props

for the tows. Changeover took about .6 hrs using pre- printed log entries

and torque was written on spinner front plate. Fine if the Tech is nearby.

The problem is what if they are not? I hate to spend more time driving

than what the task takes.

There have always been “ rumors” of a “ split “ belt that would not

require prop removal to change.

There are folks that secure a belt to the Case so it could be installed

without removing the prop. Technically log entry still needed though.
 
Gary Ward said:
Thinking back I did tighten that new belt pretty tight thinking it was going to stretch a little being new. Bottom line I think I tighten it too tight. Have done it a hundred times on car and trucks. I screwed myself this time.
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From the 1977 C172 service manual, page 16-12:

1724347053046.png

You will find this considerably less than you might be used to.
 
Link belt. Not so sure if kosher in IMC.

1724348647457.png
 
For AL12-C60, the Brush Assy looks to be P/N 10-1020. I am having trouble finding the P/N for the brushes alone. ALE-1013AS shows up but it's not clear these will fit.
 
Hartzell came back pretty quickly and were helpful, which was a pleasant surprise. They stated that TBO is unlimited as long as you check and replace the brushes as needed, and they provided the relevant documentation.
 
Katamarino said:
these units cannot be overhauled by third parties.
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I think you're asking the wrong question. You don't want an overhaul, you want an IRAN, inspect and repair as necessary. Basically clean it up, take a look at the bearings (and replace if indicated) and replace the brushes. No overhaul required or desirable.

Paul
 
PaulMillner said:
I think you're asking the wrong question. You don't want an overhaul, you want an IRAN, inspect and repair as necessary. Basically clean it up, take a look at the bearings (and replace if indicated) and replace the brushes. No overhaul required or desirable.

Paul
Click to expand...
Agreed.
 
Magman said:
An issue with Belt replacement on Lycomings is the prop must come off

to do so. This can make the task far more complex; particularly with

some Constant Speed. It is a task that requires an A & P to sign off.
Click to expand...
The best part is safetying the roll pin captured nuts on many Lyc props.
 
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