CIRRUS AIRPLANE MAINTENANCE MANUAL MODELS SR22 AND SR22T
24-30
Page 11
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EFFECTIVITY:
G. ALT 1 and ALT 2 Fail Lights
Serials w/o Perspective Avionics: Two amber colored alternator fail lights are located in the annunciator
panel. The lights provide warning of a overloaded or inoperative alternator. If either alternator gener-
ates less than 2 amps (approximately), the corresponding annunciator light will illuminate steady. If
either alternator becomes overloaded, the corresponding annunciator light will flash approximately 40
times per minute.
Serials 22-0002 thru 22-1601, 22-1603 thru 22-1643, 22-1645 thru 22-1662: The ALT 1 and ALT 2 fail
lights are operated by circuits in the MCU and current sensors on the ALT 1 and ALT 2 output lines.
Serials 22-1602, 22-1644, 22-1663 & subs w/o Perspective Avionics: The ALT 1 and ALT 2 fail lights
are operated by the data acquisition unit. The DAU monitors a voltage drop across the current shunts
in the MCU on the ALT 1 and ALT 2 output lines.
Serials w/ Perspective Avionics: All annunciations are displayed on the MFD as part of the Crew Alert-
ing System (CAS).The GEA 71 engine airframe interface will cause the ALT 1 and ALT 2 warning light
to illuminate on the MFD. If either alternator generates less than 2 amps (approximately), an amber
alert will illuminate on the MFD. If either alternator becomes overloaded, a green alert will illuminate on
the MFD.
H. Volt and Ampere Meter (See Figure 24-308)
Serials 22-0002 thru 22-1601, 22-1603 thru 22-1643, 22-1645 thru 22-1662: A combination Volt 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 INST LIGHTS circuit breaker on Main Bus 1.
Serials 22-0002 thru 22-0782: The AMP pointer sweeps a scale from -60 to +60 amps with zero at the
9 o'clock position.
Serials 22-0783 thru 22-1601, 22-1603 thru 22-1643, 22-1645 thru 22-1662: The AMP pointer sweeps
a scale from -100 to +100 amps with zero at the 9 o'clock position.
The ammeter will indicate the current generation provided by Alternator 1, Alternator 2, and the charge
or discharge status of battery 1.
The VOLT pointer sweeps a scale from 16 to 32 volts. The voltage indication for the Volt / Ampere
Meter is measured off the annunciator circuit breaker which is on the Essential Bus. Main Bus voltage
(measured at the engine instrument circuit breaker) is displayed on the clock voltmeter for reference.
Serials 22-1602, 22-1644, 22-1663 & subs w/o Perspective Avionics: Main and Essential Bus voltages
are shown as text in the electrical data field located in the mid-right section of the MFD and are also
continuously displayed in the voltage parameters field located in the upper left corner of the PFD. The
MFD and PFD receive the voltage signals via the DAU as measured directly off the Main and Essential
Buses.
In the event Main Bus voltage is less than 24.5v or exceeds 32.0v the MFD will display “Check Main
Bus” in a yellow advisory box in the lower right corner of the MFD.
In the event Essential Bus voltage is less than 24.5v or exceeds 32.0v the MFD will display “Check
Essential Bus” in a red advisory box in the lower right corner of the MFD.
Alternator 1 and Alternator 2 ampere output are shown as text in the electrical data field located in the
mid-right section of the MFD. The MFD and PFD receive the amp signals via the DAU as derived from
current shunts located in the MCU.
In the event Alternator 1 or Alternator 2 ampere output is less than 2 amps for 20 seconds or more, the
MFD will display “Check ALT 1” or “Check ALT 2” respectively, in a yellow advisory box in the lower
right corner of the MFD.
28 VDC for the digital instrument operation is supplied through the 2-amp ANNUN / ENGINE INST cir-
cuit breaker on the Avionics Essential Bus.
15 Dec 2014
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