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2011-11-20 22:01:37
Electrical Power Generation

Electrical Power Generation
Show Answers:

  1. Name the 3 things needed to create electricty?
    • flux
    • change in flux
    • conductor
  2. What component has AC go into it and DC come out?
  3. How does a commutor retain residual magnetism in order to start?
    By using field coils
  4. What is the name of the rotating component in the magnetic circuit of the commutor?
    Armature-creates its own magnetism when it rotates
  5. What is the purpose of lap windings?
    Stabilizes the magnetic field, keeps it from fluxuating
  6. 'Causes brushes to spark where there is potential difference' is defined by what term?
    Armature Reaction
  7. Who is power extracted off the commutator segments?
    by using Carbon brushes
  8. Name 3 types of generators
    Series, Compound, and Shunt wound
  9. Define Series Wound?
    field and Armature are connected in series (not used on AC)
  10. Define Shunt Wound?
    field is in parallel with the load, if load increases, field decreases due to voltage drop across generator(used in AC)
  11. What is the name of the coil that is stationary and uses both series and parallel coil?
    Compund Wound
  12. How can you define a offset commuator?
    Correction Armature Reaction, can also use interpoles places in between main poles
  13. Define the coming in speed on a generator?
    The speed at which the EMF generatoores pushes electrons into the battery
  14. Terminal I.D. on large generators
    • B-Power
    • A-coil
    • E-ground
  15. Define A and B type generators
    • A-points after field
    • B-points before field
  16. Name 3 tests performed on a generator to test for serviceability?
    Open Windings, Shorted Windings, Grounded Windings
  17. How do you test for open windings?
    mulit-meter-commutotor to shaft
  18. How do you test for Shorted Windings?
    Check for insulation leak or bridging commuator with hack saw blade
  19. How do you check for grounded windings ?
    insulation leak to ground, check with a multi-meter
  20. How dows a alternator differ from a generator?
    produces lots of flux and magnetic power at low RPM, produces rated power at low RPM. contains an electromagnetic coil that produces lines of flux for the rotating field
  21. What are the two configurations of alternators?
    Y and Delta wound
  22. How is a CSD controlled?
  23. How does a intergrated Drive Generator work?
    changes RPM to provide a constant RPM to generator
  24. How could you describe a Var. Speed Constant Freq?
    Solid state circuity converts output of generator to constant freq delivered to bus
  25. Define a rotary inverter?
    Input DC to a DC motor that turn at a constant speed. Output is AC from a single phase. DC excitiable field to vary output.
  26. Define a Static Inverter?
    DC Input, solid state circuity produces AC output
  27. What is the difference between an inverter and a rectifier?
    • Inverter-DC to AC
    • Rectifier-AC to DC
  28. In a solid state regulator, what can conduct electricty if its reversed biased?
    Zener diode
  29. The power supplied to the alternator field of a DC alternator is?
  30. How is the battery connected to the A+ terminal of the alternator prevented from discharging through the alternator?
    Diodes in the rectifier
  31. Name 3 devices used to regulate speed ?
    • IDG
    • CSD
    • VSCF
  32. What supplies power for the field to the exciter generator in a high output brushless alternator?
    Permanet Magnet
  33. if you spin a DC motor, it will generate electricty. True/false?
    True-residual magnetisum
  34. What 2 components are required in a DC motor?
    Field and conductor
  35. What are some of the factors effecting torque in a motor?
    • current going through the armmature
    • strenght of the magnetic field
    • the number of poles
    • number of windings on armmature
    • position of coil in the field
  36. What type of application would you used a series wound DC motor?
    high torque at low speed-starter, flaps
  37. What type of application would you use a shunt wound DC motor?
    constant speed applications fan field is in parallel with armmature
  38. How can you control the speed of a series wound motor?
    By varying the current through the armmature, bypass armmature with rehorstat
  39. Whats a reversible DC motor?
    Split Field, 2 field winding wound in different directions
  40. How can the polarity of a reversible DC motor be changed?
    by using a double pole double throw swithch
  41. What is the part called in a AC motor that rotates?
    Squrriel cage
  42. Name 3 types of AC motors
    • Universal
    • Induction
    • Synchronous
  43. Define a universal Motor?
    • Will operate on both AC and DC
    • can be reversed easily
    • uses commutator and brushes
  44. How does the Induction motor produce electricty?
    uses pole shoes that create a magnetic field but also induce current flow into squirrel cage (no physical connection)
  45. How is torque generated for starting a AC motor?
    Capacitors and Stators cause field to be out of phase to generate starting torque
  46. How is a 3 phase AC motor wired so it will start?
    • wired so it will induce current at any point
    • self starting
    • can be reversed by changing leads
  47. What are the 3 energy losses in electric motors?
    Electrical-copper loss due to heat generated

    Iron-Hyeteresis, residual magnetisum due to electromagnetism, resist magnetism in opposite direction

    Eddy Current-current flowing in armature core, material and field cause heat to build up
  48. Define electrical load analysis, and when is it done?
    • The summation of electrical loads as defined by the equip manufacturer
    • -must be done if your going to modify electrical system
  49. Where would a ammeter be located in a electrical system?
    between the battery and the bus
  50. define three thing about the hot bus?
    • essential loads
    • emergency loads
    • no disconnect
  51. What is a inverter used for ?
    Used to provide varying AC voltages in AC circuit
  52. "divided so you can isolate breaker so you can still fly if you were to lose a component" is a definition of what type of system?
    Split bus
  53. What does a limit switch do when activated?
    cuts off power to the motor
  54. What type of aircraft would you typically find a split bus system?
    twin engine
  55. What are some benifits to the split bus system?
    • buses never interact with each other
    • prevents phasing problems with AC current
    • prevents out of phase generators
  56. What type of aircrafts would use a parallel bus ?
    3+ engine a/c
  57. What type of transformer is clamped over a unshielded wire and induces AC into sensing field?
    Current Transformer
  58. What does GCU
    • Generator Control Unit
    • Gen. Field Relay
    • Frequency
    • Kilowatts
    • Generator Breaker
    • Bus Tie Breaker
  59. What is a TX buss
    • Transfer Bus-feeds battery charger
    • Transformer Rectifier-turns AC to DC for Bus
    • External Power
  60. What does BITE stand for?
    Built In Test Equipment
  61. Name as many wiring considerations as you can?
    • design temp
    • flexibility
    • Abrasion resistance
    • Strength
    • Insulation
    • electrical resistance
    • weight
    • applied voltage
    • current flow
  62. What is the major differnece between copper and silver wire?
    copper corrodes
  63. What are two benifits of shielded wire?
    • eliminate radio interference
    • prevents voltage from being induced into the circuit
  64. What are co-axial cables used for ?
    used for connecting an antenna to its radio reciever or transmitter
  65. What is the Standard for wires ?
    No standard, all manufactures have there own legend
  66. What is the purpose of conduit?
    • Provides protection
    • prevent radio interference