Generator/Alternator coupling and TCM SB95-3A
Posted: Tue Sep 22, 2009 11:24 pm
At the last annual on my 170 there was slop in the alternator coupling -- you could move the alternator's rotor a few degrees back and forth with the engine stopped. This was because the rubber bushing parts in the coupling to the drive gear were pounded down and undersized. (I'm talking about TCM part number 632050, but you might have 626543s instead, if you've got an older generator installation.) According to the logbook, the alternator was last serviced (rebuilt) about 1500 hours ago. There's no entry saying that the bushings were replaced at that time, so they might be even older.
TCM SB95-3A covers this condition, and suggests removing the alternator or generator for inspection and replacement of the bushing parts (2 rubber bushings and the retainer, part # 352030). These parts cost about $30 from Aircraft Spruce. While the alternator was off the plane for this, I've had it rebuilt.
I couldn't find a copy of SB95-3A on the TCM web site or anywhere else online, so I scanned a borrowed paper copy. I have it as a PDF file if anyone wants it, but it's almost 3MB on the disk. Email me, renwickj at gmail dot com, and I'll send you a copy.
Best Regards,
John
TCM SB95-3A covers this condition, and suggests removing the alternator or generator for inspection and replacement of the bushing parts (2 rubber bushings and the retainer, part # 352030). These parts cost about $30 from Aircraft Spruce. While the alternator was off the plane for this, I've had it rebuilt.
I couldn't find a copy of SB95-3A on the TCM web site or anywhere else online, so I scanned a borrowed paper copy. I have it as a PDF file if anyone wants it, but it's almost 3MB on the disk. Email me, renwickj at gmail dot com, and I'll send you a copy.
Best Regards,
John