Piper Arrow PA-28R-201 Pilot Operating Handbook page 198

PA-28R-201, ARROW
7.17 ELECTRICAL
Secondary power is provided by a 12-volt, 35-ampere-hour
The ammeter
shows
the electrical load placed on the system. With all the electrical
off, and the battery master (BATT
equipment
switches on, the ammeter
(ALTR)
battery. As each electrical unit isswitched on, the ammeter
total ampere draw of all the units including the
average continuous load for night flying with radios on is about 30 amperes.
The 30 ampere value plus 2 amperes for charging the battery will then show
on the ammeter, indicating the alternator is fimctioning properly.
Solenoids, provided
control high current draiü functions remotely from the cabin.
7.19 VACUUM SYSTEM
The vacuum
instruments.This includes the directionaland attitude gyros when
The system consists of an engine vacuum
and the necessary plumbing.
The vacuum
pump
air/oil separator and its plumbing. A shear drive protects the engine from
damage. Ifthe drive shears the gyros willbecome inoperative.
The vacuum gauge, mounted
Figure 7-21) provides valuable information to the pilot about the operation
system. A decrease in pressure in a system thathas remained
of the vacuum
constant over an extended period, may
possibly a sticking vacuum
indicator light is provided in the annunciator panel). Zero pressure would
indicate a sheared pump
collapsed line.In the event of any gauge variationfrom the norm, the pilot
should have a mechanic check the system to prevent possible damage
system components
12, 1995
ISSUED: JULY
HB-PQY, Page: 7-17-(0)
SYSTEM
(continued)
as installed does not show
will indicate the
in• the battery and startçr circuits, are used to
is designed
system
is a dry type pump
on the right instrument panel, (refer to
regulator or leak in system
drive, defective pump, possibly a defective gauge or
or eventual failure of the system.
DESCRIOPERATION
battery discharge; rather it
MASTR)
charging rate of the
willindicate the
battery. For example, the
to operate
the air driven gyro
pump, a vacuum regulator, a filter
which eliminates the need for an
indicate a dirty filter, dirty screens,
(a low vacuum
REPORT:
Issued: JULY 12, 1995
SECTION 7
battery.
and alternator
installed.
to the
VB-1612
7i 7
7-17