SF340 Electrical Systems

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  1. What are the power sources for the DC electrical system? 5-1
    • Batteries
    • External power
    • Generators
  2. What are the 4 separate parts of the electrical system? 5-1
    28V DC (main & emergency), 115/26V AC, “wild” frequency 115V AC
  3. What makes up the 28V DC electrical system? 5-1
    2 Main Batteries and 1 Emergency Battery, 2 Engine Generators, and External PWR
  4. How many Ni-Cad batteries does the Saab 340 have? 5-2
    2
  5. What type of main batteries does the Saab 340 have? 5-2
    24 volt 43 Amp hour Ni-Cad batteries
  6. Where are the main batteries located? 5-2
    In the respective wing-fuselage fairing
  7. How are the batteries ventilated for cooling? 5-2
    By ram air in flight, and fans on the ground
  8. What bus is used for battery charging? 5-2
    Respective GEN bus with at least one generator online
  9. Which bus is the right battery connected to? 5-2
    Right GEN bus
  10. What powers the Emergency Bus? 5-3
    The L BAT BUS (batteries must be ON/OVRD) or the Emergency Battery
  11. When does the Emergency battery begin to power the EMER BUS? 5-3
    When the L Battery power is lost
  12. Where is the Emergency Battery located? 5-3
    Avionics rack
  13. What is the power source for the emergency power system? 5-3
    Powered from the 28V DC system or the emergency battery
  14. What is indicated by an illuminated NO BAT START light? 5-3
    Battery temp has reached 57ºC
  15. What is indicated by an illuminated BAT HOT light? 5-3
    Battery has reached 71ºC
  16. What is indicated by an illuminated EMER PWR light? 5-3
    Either the emergency bus is not supplied power or the battery had decreased below 24V
  17. What is the purpose of the Series/Parallel relay? 5-3
    During a battery start of the first engine the batteries are connected in series to produce 48 volts.
  18. What type of Battery is used for the Emergency battery? 5-3
    24 volt 5 amp hour lead acid battery
  19. What is indicated by an illuminated L/R BAT HOT light? 5-3
    Associated battery temp has reached 71ºC
  20. What other light(s) would be on when a BAT HOT light is illuminated? 5-3
    • NO BAT START
    • BAT
    • ELEC↑ on CWP
  21. What automatically happens when a battery temp reaches 71ºC? 5-3
    BAT relay opens
  22. Can the battery supply power to the GEN bus with a BAT HOT? 5-3
    Yes, in an emergency the BAT switch can be set to OVRD
  23. What would cause the GPU to automatically disconnect? 5-4
    • Overvoltage (>31v)
    • Under voltage (<10v)
    • Voltage drops below 10 volts with start switch held to L or R
  24. What is the voltage limit during a start with the start switch held to start? 5-4
    Voltage may drop to 7 volts
  25. What is the amperage of the 28V GPU? 5-4
    1200-1600 amps
  26. What is the minimum voltage required to get the magnetic latch to close for GPU usage? 5-4
    10 volts
  27. What does the blue EXT PWR AVAIL light indicate? 5-5
    GPU is connected to the A/C and supplying at least 7 volts
  28. How many generators on each engine? 5-5&25
    2 (DC & AC)
  29. When is the starter/generator acting as a starter? 5-5
    During engine start when Ng is between 0-55%
  30. Are batteries being used for a cross generator start? 5-5
    Yes, the batteries assist the generator to achieve a faster cooler start
  31. When is the GEN relay automatically opened? 5-6
    • GCU detects a malfunction (except overheating)
    • External power is used
    • Fire handle has been pulled
  32. When is the Gen relay light expected to be on? 5-6
    • When the respective Gen switch is off
    • When external power is powering the A/C
    • When a Fire handle has been pulled
    • When engine Ng is less than 55%
    • With a failure of the Gen
  33. How many electrical buses does the Saab 340 have? 5-6&7
    27 (21 is incorrect)
  34. What minimum Ng is required to connect the starter/generator to the GEN BUS? 5-6
    55%
  35. What is indicated by an illuminated L/R GEN light? 5-6
    The respective Gen relay is open (gen offline)
  36. The starter/generators are rated at what voltage? 5-6
    28 volts
  37. An illuminated GEN OV TEMP light on the overhead panel indicates what? 5-6
    Generator is overheated (150º)
  38. Can the Generators be “online” with EXT PWR on? 5-6
    No, the relay automatically opens
  39. What 3 conditions must be met for the GEN relay to close? 5-6
    • EXT PWR must be off
    • Engine start complete
    • Gen field reset
  40. What is indicated by an illuminated L/R MAIN BUS light? 5-8
    The associated main bus is unpowered
  41. What is indicated by an illuminated L/R ESS BUS light? 5-9
    Associated bus is not powered
  42. What is the purpose of the Bus Tie relay? 5-9
    To connect the left and right busses to run off one power source
  43. What is indicated by an illuminated BUS TIE CONN light? 5-9
    The bus tie relay is closed
  44. What are three reasons the Bus Tie relay closes? 5-9
    • EXT PWR is on
    • Only one Generator is operating
    • Either the LEFT or BOTH Batteries are on
  45. What is the purpose of the bus tie over-current relay? 5-9
    To protect the Main Distribution system in case of a short
  46. Bus Tie relay opens if the over-current exceeds how many amps? 5-9
    800 amps
  47. Can the Bus Tie over-current be reset manually? 5-9
    Yes, through the K-1 reset button
  48. What is required to close the Utility Bus relay (RCCB)? 5-9
    EXT PWR on or both generators on
  49. What powers the Emergency Avionics Bus? 5-9
    The Emergency Bus, when the ESS AVION switch is on
  50. Where does the battery bus receive power from normally? 5-11
    Gen bus
  51. The left battery is connected to which bus? 5-11
    Start bus
  52. While on battery power alone what lights illuminate on the DC ELEC panel? 5-14
    • BUS TIE CONN
    • L/R GEN
    • L/R MAIN BUS
    • EMER PWR (If BUS is below 24V)
  53. With the GPU powering the A/C what lights illuminate on the DC ELEC panel? 5-15
    • White EXT PWR
    • L/R GEN
    • L/R BAT
  54. What is the power source for the 115/26V AC system? 5-22
    2 115/26V AC inverters powered by the DC system
  55. What is indicated by an illuminated INVERTER light? 5-22
    Inverter switch is set to OFF or associated 115 volt Inverter has failed
  56. With a Failure of the 26V output of the inverter what warnings are given? 5-22
    No CWP warning or cautions, but an RMI failure and VOR CDI failure will occur
  57. What is the power source for the “wild” frequency 115V AC system? 5-25
    2 engine driven AC generators
  58. What is the “wild” frequency 115V AC power used for? 5-25
    Ice protection
  59. Why is the AC GEN called the “wild” frequency? 5-25
    Frequency varies with prop RPM, (460Hz to 640Hz)
  60. Where is the “wild” frequency generator located? 5-25
    On the prop gear box
  61. What is the minimum prop RPM for an AC GEN to supply power? 5-25
    1000 RPM
  62. If prop RPM drops below 1000 RPM, how is the AC GEN reset? 5-25
    Automatically resets when prop RPM increases above 1000 RPM
  63. What does an illuminated AC GEN light indicate? 5-32
    Generator is off line
  64. What items can be powered by the Emergency battery? 5-41
    • Audio system backup power
    • Bus tie CONN
    • Engine Fire Warning
    • Tailpipe hot Detection
    • WEU Backup
    • Emergency voltage indication
    • Emergency Avionics Bus
    • Stepdown from 24V to 6V for lighting of: Magnetic Compass, OBS, Pressurization, Standby Altimeter, Standby Attitude Indicator, Standby Airspeed
  65. What items are on the EMER AVIONICS BUS? 5-41
    VHF COMM 1, Standby Attitude Indicator
  66. What 3 conditions must be met for a battery relay to close?
    • BAT switch on
    • EXT PWR off
    • Battery temp below 71ºC
  67. What cools the DC generator?
    Ram air in flight and fans on the ground
Author
ID
88277
Card Set
SF340 Electrical Systems
Description
Colgan Air Saab 340 Chapter 5 - Electrical
Updated
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