1. Home
  2. Flashcards
  3. Preview

3ph Power Fundamentals

  1. A sine wave has a maximum value of 230V. What is the voltage after 38 degrees of rotation?
    • E(INST) = E(MAX) x sin(angle in degrees)
    • 141.6v
  2. How do you calculate instantaneous voltage when the maximum voltage and the angle are known?
    E(INST) = E(MAX) x sin(angle in degrees)
  3. How do you calculate the angle of a sine wave when maximum voltage and instantaneous voltage are known?
    sin(angle in degrees) = E(INST) / E(MAX)
  4. In a wye connection ELine =
    ELine = 1.73 x EPhase
  5. In a wye connection ILine =
    ILine = IPhase
  6. In a delta connection ELine =
    ELine = EPhase
  7. In a delta connection ILine =
    ILine = 1.73 x IPhase
  8. Line voltage and line current in a 3 phase connection are known. What is the formula for calculating power (VA)?
    VA = 1.73 x ELine x ILine
  9. Phase voltage and Phase current in a 3 phase connection are known. What is the formula for calculating power (VA)?
    VA = 3 x Ephase x IPhase
  10. Draw and label the power triangle. What is the “Real Power”? What is the “reactive power”? What is the “apparent power”?
  11. Real Power
    Measured in watts (W), is produced only when electrical energy is converted into some other form.
  12. Reactive Power
    Quantified as VARs when there is no net energy transfer of energy to a load. Calculated by multiplying reactive voltage by reactive current. Can be produced by inductive or capacitive loads.
  13. Apparent Power
    Quantified as VA. The complex vector sum of Real and Reactive Power and is what is measured in a circuit
  14. A wye-connected load has a voltage of 480V applied to it. What is the voltage across each phase?
    277V
  15. A wye-connected load has a phase current of 25A. How much current is flowing through the lines supplying power to the load?
    25A
  16. A delta connection has voltage of 560V connected to it. How much voltage is dropped across each phase?
    560V
  17. A delta connection has 30A of current flowing through each phase winding. How much current is flowing through each of the lines supplying power to the load?
    52A
  18. A three phase load has a phase voltage of 240V and a phase current of 18A. What is the apparent power of this load?
    12.96KVA
  19. A three phase wye connected load has a phase voltage of 240V and a phase current of 18A what would be the line voltage and line current supplying the load?
    416V
  20. An alternator with a line voltage of 2400V supplies a delta-connected load. The line current supplied to the load is a 40A. Assuming the load is a balanced three-phase load, what is the impedance of each phase?
    104 ohms
  21. An alternator with a line voltage of 2400V supplies a delta-connected load. The line current supplied to the load is a 40A. What is the apparent power?
    166 277 VA
Author
sheac137
ID
359352
Card Set
3ph Power Fundamentals
Description
Updated

  1. Home
  2. Flashcards
  3. Preview