Piper PA-32R-301T SARATOGA S, Maintenance Manual

Page: 224 / 956

D.C. GENERATION (cont.)
(8) Checking Alternator Belt Tension (cont.)
Chart 3
Prestolite Alternator Belt Tension
C 90 Amp Ford Alternator System (Refer to Figure 16.)
(1) 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.
(a) The front housing 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.
(b) The rear housing 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 17 for Terminal
identification.)
(c) The stator core and coil assembly consists of a number of steel stampings riveted together to
form the stator core which contains 36 equally spaced vertical slots to accommodate the sta-
tor coil windings. (Refer to Figure 18.)
(d) The rotor core and coil assembly 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.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
24-30-00
Page 24-19
Reissued: July 1, 1993
1K19
Torque indicated at
Width of Belt Condition alternator pulley
3/8 inch New 11 to 13 ft-lbs
3/8 inch Used 7 to 9 ft-lbs
1/2 inch New 13 to 15 ft-lbs
1/2 inch Used 9 to 11 ft-lbs
—NOTE—
Higher tension specified for new belts compensates for
initial stretch that takes place as soon as it is operated. Do
not apply higher tensions to previously used belts