Jasco 6560T Alternator Drive Coupling Components

[gfeher]

I have a Jasco 6560T alternator (from Skytronics) on my plane (stock C-145-2) put on by the previous owner. I have not taken it off, so I haven't seen the drive components. Anyone know whether the drive components (rubber bushings, retainer, hub, drive gear, etc.) are identical to the ones for the original generator? Here's a shot from the Spruce website showing what I understand are the current part numbers for the original generator coupling components:

Question is whether the same parts are used for the Jasco 6560T. I think they are, but the paperwork for my 6560T installation shows a few different part numbers and I'm trying to determine if I'm just dealing with superseded part numbers or actual different parts. Thanks in advance.

[n2582d]

Gene,
Here’s a clip from page 33 of the Jasco Alternator Troubleshooting PDF:

This discussion might be of interest if you are pulling your Jasco alternator. You owe me a beer!

[jlwild]

I just replaced part 08-13958 (pair of rubber bushings) at 650 hours on my Skytronics alternator. Paper work with plane says to inspect every 500 hours. Per my AI, the part is common to most continental generators and alternators. Also, part is available from many sources and easy to replace.

[gfeher]

Jim, the Skytronics maintenance instructions now say to inspect them every 250 hours, which is inconsistent with Continental SB95-3B and the Continental Maintenance Manual M-0, which say to insect them every 500 hours. Seems like overkill.

Gary, I read that thread before I did my post, but it didn't completely answer my question. That's where I got the impression that the drive coupling components for the Jasco 6560T were the same as for the stock generator. It's just that my paperwork identified part numbers different from those in that thread or in the Continental IPC. (I'll still buy you a beer though. ) It's not worth posting the various part numbers in my paperwork though because after running all the part numbers through the part number history lookup on Continental's website, I've now confirmed that with the exception of the sleeve and the possible exception of the drive gear and hub, all of the parts are the same as those used for the stock generators. (Here's a link to the Continental parts history lookup for anyone who's not familiar with it: http://www.continentalmotors.aero/suppo ... story.aspx) The various part numbers were just different numbers in the chain of superseding part numbers.

For anyone interested, here are the part numbers identified in Fig 18 of the Continental IPC (X30014), and if superseded the current numbers, common to the drive couplings of both the stock generators and the Jasco 6560T alternator:

Bushings (rubber) (2 needed but sold as a pair): 626543 superseded by 632050
Retainer: 352030 superseded by 653982
Nut: 530412 (castle hex .31-24)
Cotter Pin: 2501 superseded by MS24665-132 (1/16” D x ½” L)
Gasket: 36100 superseded by 652072 (also Superior SA36100)

According to the paperwork that came with my alternator, the Jasco 6560T does not use the sleeve 530407 shown In FIg 18 of the Continental IPC because the drive shaft has a larger diameter than the stock generators. For this reason as well, I believe that the drive gear and hub used for the 6560T may be different than the ones used for the stock generators. At least according to my paperwork, the part numbers are different:

Drive Gear and Hub Part Numbers for Stock Generators as Identified in Fig 18 of Continental IPC:
Drive Gear: 531325
Hub: 530406 superseded by 653983

Drive Gear and Hub Part Numbers for 6560T Alternator as Identified in Skytronics Paperwork:
Drive Gear: 530997
Hub: 352029
Note: The Continental parts history look up indicates that both of these part numbers for the 6560T alternator are "inactive" and superseded by "RFQ only" whatever that means.

I hope this hasn't been too confusing.

[GAHorn]

I will add that 500 hours seems to be the half-life of generator* and alternator brushes as well, so it's probably a good time to pull them and service the entire assy anyway.
The Jasco units are unique in that no one but Skytronics is approved to service them. However, other generators and alternators can be serviced by most aircraft electrical accessory shops.... including AeroTech of Louisville... whose owner was a presenter at our Bardstown convention where he offered to service our Member's units for $100 if sent in prior to failure.

*I inspected my 35A generator brushes at 500 hours and found them at half-length compared to new. (3/8" compared to 3/4")
I replaced them "in situ"... by removing the shield, retracting the holders/springs, and removing the old, installing the new, and reversing the procedure. It was very simple job to do, and it worked fine for me. The approved process will run them in on the bench for an hour to match-up the commutator with the brushes, however.
The attraction of having John at AeroTech do the job for you is the complete process and proper re-sealing of the oil seal and bushings as well as the cleaning/re-cutting/under-cutting of the commutator mica as req'd.... as most owners are unprepared/ill-equipped to do that job.
Be certain to replace the large gasket completely...do not cut it..., including the tach-drive portion, and to also replace that tack drive oil seal all at the same time.

[gfeher]

Good info George. The paperwork for my alternator says that it must be returned to Skytronics for servicing at 1000 hrs. I can only imagine what that will cost. I'm in your camp. If the previous owner hadn't changed to the alternator, I would have kept the 35A generator that was on it, especially now that lighter loads are possible with LEDs and components requiring less power. I know that my alternator weighs less and has 50A capacity. But I think that maintenance is easier and cheaper with the generator. (Despite what Skytronics says.)