Alternator Reliability Poll

[keijidosha]

45 amp ?Denso? 14684 alternator w/ internal regulator and AeroElectric over-voltage crowbar mod purchased Sept 2010. Installed on O-320 with blast tube, VFR panel, incandescent lighting. Flying since 2014, currently has 120 hours. Too young to vote.

[F1Boss]

PP gear drive primary unit - one of the prototypes. 225hrs so far - just had to replace the shear coupling (August 2016). ACS has these couplings for $15 ea - Hartzell (new owners of PP) wanted a smooth $100 for one.

This on a 550 Continental - very smooth running engine. I doubt this was a vibration related issue.

I have seen 35A charge out of this unit; normal load is 7-8A or so. No blast tube installed.

I'll NOT have one of these on my next bird. Ordered up 2ea B&C gear drive 40A units - one to replace this one, and one for the next build.

BTW it seem many RV pilots come to Taylor Texas to let their alternators die in peace. I keep an O/H'd ND on the shelf, and since the last go-round, I also keep spare brushes and rectifier assys on the shelf too. I'm getting too good at changing the rectifier assy out! Our local alternator shop wonders how is it that I work on so many alternators?

Carry on!
Mark

[Toobuilder]

70 amp ND from NAPA auto parts. 300+ hours on the Rocket with no issues

[Bill Dicus]

Originally Posted by keijidosha

45 amp ?Denso? 14684 alternator w/ internal regulator and AeroElectric over-voltage crowbar mod purchased Sept 2010. Installed on O-320 with blast tube, VFR panel, incandescent lighting. Flying since 2014, currently has 120 hours. Too young to vote.

Keijidosha! Could you show your wiring scheme for the OVP? Thanks in advance..

[keijidosha]

Originally Posted by Bill Dicus

Keijidosha! Could you show your wiring scheme for the OVP? Thanks in advance..

Not my drawing, but similar to what I have http://www.aeroelectric.com/Catalog/...allation_A.pdf

[rotoiti]

RV-10, B&C alternator.

Two "alternator" failures in 290 hours. One was a mystery field wire issue, much like scard's, solved by routing another field wire. Another was a failed alternator belt pulley (I have an a/c system). No failures of the alternator itself.

[Bill Dicus]

Keijidosha: Thanks - got and will wire it up soon. Sorry for slow response!

[hgerhardt]

It seems to me that most of us on this board look at alternators as a monolithic entity, when really they are an assembly of fairly simple parts.

Plane Power and B&C both start out as Denso alternators. PP makes a mod to the internal reg to have absolute control over field current + adding an overvoltage module, while B&C uses a version similar to what older Chryslers had with an external regulator.

It sure would make this poll more useful if all the people who responded that they had a failure would just disassemble their units and diagnose what actually failed. Maybe we can find a pattern of similarly failed parts and come up with fixes to improve reliability. If you don't know about the inner workings of an alternator, go find someone who does know.

So far, this poll is nothing but a Ford vs. Chevy battle. Let's improve it!

Heinrich

Generic Denso alternator:


Plane Power:


B&C:


Notice how they all pretty much look the same?

[bret]

And....maybe add to the list, internal or external regulator failure rate. I guess the list can get crazy, thermal electrical failure or mechanical?

[lawrence]

30 amp vans alternator from early 90's.
Bearings were getting noisy at 23 years and 630 tach hours.
External regulator did fail at this time. Replaced both with similar.