NCEES Electrical Engineering 2 — Questions and Answers
Question 1: According to the NCEES PE Electrical exam, the National Electrical Code (NEC) is primarily concerned with:
- Utility transmission line design
- Safe installation of electrical wiring and equipment (Correct answer)
- Power plant generator ratings
- Telecommunication network standards
Correct answer: Safe installation of electrical wiring and equipment
The NEC (NFPA 70) establishes minimum safety standards for the installation of electrical wiring and equipment.
Question 2: In NCEES PE Electrical practice, the resonant frequency of a series RLC circuit is:
- f₀ = 1/(2π√LC) (Correct answer)
- f₀ = 2π√LC
- f₀ = √(LC)/2π
- f₀ = R/(2πL)
Correct answer: f₀ = 1/(2π√LC)
Resonant frequency f₀ = 1/(2π√LC): at resonance, inductive and capacitive reactances cancel.
Question 3: For the NCEES PE Electrical exam, the power factor of an AC circuit is defined as:
- Ratio of reactive power to apparent power
- Ratio of real power to apparent power (cos θ) (Correct answer)
- Ratio of apparent power to real power
- The phase angle between voltage and current
Correct answer: Ratio of real power to apparent power (cos θ)
Power factor = P/S = cos θ, where P is real power (W) and S is apparent power (VA).
Question 4: In NCEES PE Electrical design, a per-unit system is used in power systems to:
- Convert AC to DC quantities
- Normalize system quantities to base values, simplifying calculations across voltage levels (Correct answer)
- Calculate fault impedances in ohms only
- Replace three-phase with single-phase analysis exclusively
Correct answer: Normalize system quantities to base values, simplifying calculations across voltage levels
The per-unit system normalizes voltages, currents, and impedances to base values, eliminating transformer turns ratios from calculations.
Question 5: On the NCEES PE Electrical exam, a symmetrical three-phase fault analysis uses which method to find fault currents?
- Thevenin equivalent circuit at the fault point (Correct answer)
- Norton equivalent with short-circuit admittance
- Direct superposition of line voltages
- Per-phase load flow analysis
Correct answer: Thevenin equivalent circuit at the fault point
Symmetrical three-phase faults are analyzed using the Thevenin equivalent impedance at the fault bus to compute fault current.
Question 6: In NCEES PE Electrical engineering, the speed of a synchronous generator in rpm is related to the number of poles P and frequency f by:
- N = 60f/P
- N = 120f/P (Correct answer)
- N = Pf/120
- N = 2f/P
Correct answer: N = 120f/P
Synchronous speed N = 120f/P rpm, where f is frequency in Hz and P is number of poles.
NCEES Electrical Engineering 2
According to the NCEES PE Electrical exam, the National Electrical Code (NEC) is primarily concerned with: