Electrical Flashcards
The minimum battery voltage for APU start is?
23 Volts
When a source of power is connected to a bus system, _____________occurs
It automatically disconnects an existing source.
What does a GRD POWER AVAILABLE light do?
Provides flight deck indication that AC ground power is connected to the aircraft and meets aircraft power quality standards.
If the BUS TRANS switch is in the AUTO position and the source powering the transfer bus is disconnected or fails, what does the source powering the opposite bus through the BTBs do?
Automatically picks up the unpowered transfer bus.
What do the three transformer rectifier (TR) units do?
Convert 115- volt AC to 28-volt DC
Inflight, when does an Amber TR UNIT light illuminate?
TR1 or TR2 and TR3 has failed
How long does a fully charged battery have sufficient capacity to provide electrical power for? (Single battery configuration)
A minimum of 30 minutes
When does an amber BAT DISCHARGE light illuminate?
Excessive battery discharge is detected
If one or more of the following busses are unpowered, ___________, it is indicated by an illuminated STANDBY PWR OFF light
All answers are correct
AC standby bud, DC standby bus and battery bus
In flight or on the ground, with the STANDBY POWER switch in AUTO (guarded position) with the loss of all AC power, the AC standby bus is powered by ____________ and the DC standby bus is powered by _________________.
The battery
The light on the overhead panel that illuminates if the APU is running and not supplying power to a bus, is the ________.
APU GEN OFF BUS
On the ground and inflight, the APU generator can supply power to ______.
Both transfer busses
The electrical system is designed to _____ during single generator operation.
Shed electrical loads incrementally
When _______ oil is sensed in the IDG, the amber DRIVE caution light is illuminated.
Low
It ___________ possible to reactive the IDG in flight after the IDG disconnect switch is used to disconnect the IDG from the engine.
Is not
Which of the following can cause IDG low oil pressure?
All Answers are correct.
(IDG automatic disconnect due to high oil temperature.
IDG disconnected through the generator drive DISCONNECT switch.)
An amber _______ light illuminates to indicate the DC system or standby system equipment has failed, while the aircraft is on the ground. This light is inhibited in flight.
ELEC
How many engine driven IDGs are used to provide primary electrical power?
Two
**OLD BANK*******
The guarded Standby Power Switch will be in __________ and the battery switch will be _______, during normal operations.
AUTO; ON
**OLD BANK*******
On the B737-800, when moving the generator (GEN) switch to ON, the _________________ by disconnecting the Previous power source and closing the generator circuit breaker.
IDG is connected to the AC Transfer Bus
