Electrical system Flashcards
What is the normal battery used for?
Used for starting and ensures emergency power
There are two batteries, what are they
Normal & emergency battery
What is the emergency batt used for?
Ensures emergency power and assists in engine starts
Describe the batteries:
Both are 24V
Ni-Cd
Main Bat is 43 amp hr
Emer bat is 15 amp hr
Electrical system is ____ volts
28 volts
Which lights work in Basic Mode (Battery only).
The F/O’s dome light STBY Compass light MIN CAB lights 3 flood lights (C side) Overhead flood light STBY instrument lights Eng inst lights L3 lights on CAP
What bus powers the Captain’s wipers?
DC BUS 1
Will the intercom system between you and the FA work in basic mode?
No. The ATTND CALL system is powered from DC BUS #2, which is NOT a Basic Mode Bus
What does the MIN CAB LT switch do, and how does it work?
The MIN CAB LT switch is used to turn on every other lateral light on the right side of the cabin. When power is lost from the DC Service Bus, a contactor will close enabling the DC ESS BUS to power every other light on the right side of the cabin when you switch in the MIN CAB LT switch. This switch is normally used in an emergency situation, such as engine fire on the ground or dual DC Gen failure
What is the difference between the ON position and the OVRD position on the battery switch?
When you select the Battery switch to the ON position, you are closing 3 relays that will connect the Hot Battery Busses to their respective “Basic Mode Busses.” (DC EMER BUS, DC ESS BUS, DC STBY BUS, AND AC STBY BUS through INV 1.) Also, in Basic Mode, both Battery Charge Contactors are open. When you select the Battery switch to the OVRD position, you are guaranteeing “Basic Mod” by forcing open both battery charge contactors (EBCC and MBCC) if for some reason they didn’t open. You are also taking away the BPCU logic. (The BPCU regulates distribution and bus isolation by automatic control of certain contactors.)
What does the undervoltage light mean?
This means the power from the Main Battery is down to 19.5 volts and it’s time to select the OVRD push-button
When in Basic Mode, what electrical configuration would you get if you push the OVRD pus-button?
Selecting the OVRD push-button enables you to power the DC STBY BUS and the #1 INV through the Emergency Battery. The rest of the relays remain the same.
What are the conditions to get an X-start fail light?
You must be on the ground and starting the second engine without external power. The X-Start fail light will only illuminate between 10-45% NH if the operating DC GEN does not assist with the start.
How do you know the BTC is closed?
Illumination of the green flow bar in the push-button. And the other half of the electrical panel is operating.
What amber lights on the Main Electric Panel will be on in Basic Mode? (Assume all push-buttons are in.)
“10 lights” When you select ON the Battery Switch without external power being AVAIL, the amber FAULT lights in both the DC GEN push-buttons, and the SHED light in the DC SVCE/UTLY BUS push-button will be illuminated. Also, both DC BUSS OFF light will be illuminated as will the Emergency Supply Arrows. The amber BUS OFF for the AC BUS #1 and the BUS OFF and INV FAULT for the AC BUS #2 will be illuminated.