Systems - Electrical Flashcards
Electrical System Voltage
28v
Electrical System Primary Components
(2) Starter-Generators (30v Starter / 28v Generator)
(3) 24v Lead Acid Batteries (BAT 1(2) 22ah, BAT 3 7ah)
(3) Static, single-phase Inverters (400hz, 115v AC)
(1) 26v Transformer (CC-50 and earlier)
Starter-Generators provide power to…
…Secondary Bus Bar
Voltage Limits for Starting
minimum 23v maximum 29v
Amperage before Second Engine Start
below 100amps
Starter-Generator functions as Starter until
60% RPM
Automatically Disconnected
Starter-Generators may be brought online as Generators at
65% RPM
RESET then ON
Cross-Generator Start Engine RPM
80%
If a fault develops on the SEC BUS the Generators will…
…be automatically transferred and provide power to the ESS Bus Bar
When can the Generators be transferred back to the SEC BUS
- on the ground
- after maintenance
- utilizing the GEN to SEC BUS switches
Each Generator Control Box protects against
overvoltage
reverse current flow
ground faults
Each Generator Control Box serves to
equalize and regulate 28v DC
provide protections
Each Generator Control Box can be tested to…
… simulate either –
- overvoltage
- ground fault
testing illuminates the GENERATOR warning light on the glareshield panel
Batteries Provide Power to…
BAT 1 - ESS BUS
BAT 2 - START BUS
AUX BAT - PRIMARY BUS
AUX BAT function during start cycle
to supply constant voltage to critical temperature indication and starting systems
