Electrical Flashcards
What kind of electrical system is the SR20 equipped with?
2 Alternator, 2 Battery, 28-Direct Volt Current (VDC) redundant system.
Negative-ground.
___________________
Alternators are controlled by the MCU (Master Control Unit) and require battery voltage for start. (not self-exciting)
ALT 1 - Belt driven, 100 Amp mounted on the right front of the engine. Regulated to 27.7 V.
ALT 2 - Belt driven, 70 Amp mounted on the left front of the engine. Regulated to 28.7 V.
____________________
BAT 1 - 24V, 11A mounted on the right firewall.
BAT 2 - 2-12V , 7A sealed lead acid batteries connected in series to make 24V. Located in a vented, acid-resistant container behind the aft cabin bulk head, below the parachute canister.
BAT 1 is charged from the Main Distribution Bus 1 in the MCU.
BAT 2 is charged from CB panel ESS BUS 1.
Draw and explain a schematic of the SR20 electrical system:
Let there be art (POH 7-50)
Batteries ____ power
Store
Alternators ____ power
produce
Buses _____ power
Manage
Switches/Relays _____ power
control
Diodes/Regulators _____ power
Measure, Protect, Regulate
What are the 5 POWER SOURCES on the SR models?
ALT 1
ALT 2
BAT 1
BAT 2
EXT PWR
What are Volts
Electric Pressure (potential energy)
What are Amps
Electric Current
Battery 1 discharge while Alt 1 is functioning normally, indicative of:
an internal power distribution failure within the MCU.
BAT 1 is charged from:
the Main Distribution Bus 1 in the MCU.
BAT 2 is charged from:
the circuit breaker panel ESS BUS 1.
The Master Control Unit (MCU) is located on the left firewall. The MCU controls:
ALT 1, ALT 2, starter, landing light, EXT PWR…
and power generation functions.
Power is supplied to the airplane circuits through 3 distribution buses contained in the MCU: ___, ___, ___
The 3 distribution buses power the:
Main Distribution Bus 1, Main Distribution Bus 2, and the Essential Distribution Bus.
associated BUSES on the circuit breaker panel.
When will the over-voltage protection relay kick an ALT offline?
31.75V
MAIN DISTRO BUS 1 and 2 are interconnected by:
What does this ensure?
An 80-amp diode.
The diode prevents ALT 2 from feeding the MAIN DISTRO BUS 1. (Additionally, ALT 2 Bus voltage being slightly higher than ALT 1 voltage further assures this separation.
(POH 7-48)
The ESS DISTRO BUS is fed by both Main Distribution Bus 1 and Main Distribution Bus 2 in the MCU through __________.
two 50-amp fuses
The MCU provides: (4 THINGS)
- ALT 1 and ALT 2 voltage regulation
- External power reverse polarity protection (diodes take care of this)
- Alternator overvoltage protection
- Electrical system health annunciations to the Integrated Avionics System
The ESS DISTRO BUS powers the ______ and ______ through 30-amp fuses located in the MCU.
- ESS BUS 1,
- ESS BUS 2.
MAIN DISTRO BUS 1 directly powers the _____ _____ through a 7.5-amp fuse, and ____, _____, and _____. (CB buses)
Landing Light
- A/C BUS 1,
- A/C BUS 2,
- MAIN BUS 3.
Main Distribution Bus 2 powers ____. _____. and _____ through 30-amp fuses located in the MCU:
- NON ESS BUS,
- MAIN BUS 1,
- MAIN BUS 2.
What does “internally rectifying” mean in regard to the alternators?
?? They convert AC to DC ??
What is the difference between AC and DC?
AC periodically reverses direction.
DC flows in only 1 direction.
