Piper COMANCHE PA-24-180 Service Manual page 544

PIPER COMANCHE
SERVICE MANUAL
FIGURE 9-3. WIRING CIRCUIT O THREE UNIT REGULATOR
openin the regulator points opens the regulator series winding circuit so that its magetic field
collapses completely. The consequence is that the magnetic field is reduced sufficiently to allow
the spirl spring to pull the armature any from the core so that the contact points again close.
This directly goruds the generator field circuit so that
nerator voltage and output icreae.
The above cycle of action again tales place ad the cycle continues at
rate of SO to 200 times
a second, regulating the voltage to a predetermined value. With the voltage thus limited the Ln-
rateo supplies varying amounts of current to meet the varyin states
of
hbattery charge
and
elec-
trical l ad.
9-24. Current Regulater.
a. The current regulator (Figure 9-3) has series windinLg a few turns of heavy wire which
carries all geneator output. The winding cor is assmhbled into a frame. A fiat steel armature is
attached to the frame by a flexible hinge so that it is just above the coe. The armature has a
contact point which is just below a stationary contact point. When the current regultor is not
operating, the tenion of a spiral spring holds the armatue away from the core so that the points
are in contact. In this position the generator field circuit is completed to gound through the
current regulator contact points in series with the voltage regulatcr contact points.
b. When the load demands are heavy, as for exstaple, when electrical devices are turned on
and the battery is in a discharged condition, the voltage may not increse
to a value sufficient to
cause the voltage regulator to operate. Consequently, gepuerator output will continue to increase
until the generator reaches rated maximum current. This is the current value for which the current
regulator is set. Therefore, when the genantor
nches
rated output, this output, flowin through
the current regulator winding, creates sufficient magnetism to pull the current regulator armatue
down and open the contact points. With the points open, resistance is inserted into the genetor
field circuit so that the genertor output is reduced.
c. As soon as the generator output starts to fll off, the magnetic field of the current regulator
ELECTRICAL SYSTEM
ISSUED: 8/11/72
3 A22