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Greetings:
According to the alternator system wiring diagram for serial numbers 337-0001 thru 337-0268 and 337-0281 thru 337-0325 there was no filter capacitor on the alternator output. 337-0269 thru 337-0280 did not have a filter capacitor either.
Beginning with 337-0327 there was a filter cap on the output (B+) of both alternators. This practice was also associated with Cessna's practice of shielding the alternator output wires and the field wires. This was done in an attempt to clean up the AC hash on the line that was interfering with ADF's and poorly isolated audio amplifiers in the radio's and audio panels.
Fortunately the Skymaster was spared from the poor tactic of putting a capacitor on the field terminal at the regulator, this was a single-engine airframe practice. We don't want the regulator driving a capacitance load.
If you review the alternator system wiring diagrams for the later Skymasters the wire shielding practice was dropped but the output capacitor remained. There is nothing wrong with having a capacitor on the output terminal of the alternator.
During an electrical system freshening there is no reason to shield the alternator output leads. It's okay to shield the field wire from the regulator to the field terminal of the alternator. Best practice is to ground the shield at the regulator end only. If you are doing a charging system freshening, running a 16 gauge field wire to the rear alternator will help to balance the output sharing of both alternators. This statement applies to the planes that use one regulator for both alternators. The 2-4 amp field load can have a noticeable voltage drop over the long field wire to the rear alternator. The heavier field wire to the rear alternator will help balance the load.
Dave
Dave
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