2G1; Alternator System (90 Amp Electrosystems); Description - Piper 6X Maintenance Manual

1. Alternator System (90 Amp Electrosystems. Inc.) (See Figure 1.)
A.

Description

The principal components of the alternator are the front housing, fan and pulley, rear housing and
terminal identification, stator core and coil assembly, rotor core and coil, brushes and holder
assembly and rectifier assembly.
(1) The front housing (1) is a die-cast aluminum part which meets design requirements for a
lightweight, non-magnetic material. This casting incorporates the bosses used to attach the
assembly to its mounting bracket. It also provides the supporting surface for the rotor shaft
front bearing and vendor identification data stamped into the front housing.
The fan and pulley are attached to the rotor shaft with a nut and lock-washer. The forward end
of the shaft is threaded to accept the nut.
(2) The rear housing (2) is also a die-cast aluminum part which supports the rotor shaft rear
bearing and provides mounting bosses for the rectifier assembly. The housing contains the
various electrical connections and openings for cooling airflow. (Refer to Figure 2 for Terminal
identification.)
(3) The stator core and coil assembly (3) consists of a number of steel stampings riveted together
to form the stator core which contains 36 equally spaced vertical slots to accommodate the
stator coil windings. (Refer to Figure 3.)
(4) The rotor core and coil assembly (4) consists of the rotor shaft, two slip rings, two rotor halves
and the coil assembly. The shaft is supported at each end by bearings. The front bearing (ball-
type) is a slip fit on the shaft and is retained in the front housing with a retainer. The rear
bearing (needle-type) is pressed into the rear housing. The slip rings, core and coil assembly
are press-fitted to the shaft with a rotor half enveloping each end of the coil.
The rotor core and coil assembly turns inside the stator core and coil assembly with a very
narrow air gap between the two assemblies, thus developing maximum magneto induction.

2G1

THE NEW PIPER AIRCRAFT, INC.
PA-32-301FT / 301XTC
MAINTENANCE MANUAL
D.C. GENERATION
Exploded View of Electrosystems Alternator
Figure 1
24-30-00
Jun 1/03
PAGE 1