Cirrus DESIGN SR20 Information Manual page 303

Cirrus Design
SR20
Illumination of ALT FAIL caution light may occur during low
RPM conditions with an electrical load on the system, such as
during a low RPM taxi. Under these conditions, the light will go
out at higher RPM.
Volt / Amp Meter
A 2¼" combination Volts and Ampere meter is mounted on the right
instrument panel immediately outboard of the oil temperature and
pressure gage. The indicator is internally lighted. 28 VDC for
instrument lighting is supplied through the 2-amp INSTRUMENT
LIGHTS circuit breaker on Main Bus 1.
The VOLT pointer sweeps a scale from 16 to 32 volts. Refer to Section
2 (Limitations) in basic POH for instrument limit markings. The voltage
indication is measured off the essential bus.
The AMP pointer sweeps a scale from –60 to +60 amps with zero at
the 9 o'clock position. The amps indication is derived from current
transducers located in the MCU function modules. Output from each
alternator and the battery is measured. The panel mounted
AMMETER SELECT switch is used to select the desired indication.
When the engine is operating and the master switch is turned on, the
ammeter indicates the charging rate applied to the battery. In the event
the alternators are not functioning or the electrical load exceeds the
output of the alternators, the ammeter indicates the battery discharge
rate. Alternator ammeter indications are positive only.
Ammeter Select Switch
The AMMETER SELECT switch on the instrument panel is used to
select the desired source of electrical current flow to be indicated on
the ammeter. The switch has three positions: ALT 1, BATT, and ALT 2.
Selecting one of the switch positions will cause the amperage output
from that device to be displayed on the ammeter.
Circuit Breakers and Fuses
Individual electrical circuits connected to the Main, Essential, and
Non-essential buses in the airplane are protected by re-settable circuit
breakers mounted on the left side of the center console. The airplane
Essential bus is supplied from the Main Buses through the 20-amp
P/N 11934-S10
Original: 09-28-99
• Note •
Section 9
Supplements
9 of 10