EEE 360 - EXAM 1 QUESTIONS WELL ANSWERED LATEST UPDATE 2026
If the power is positive, the element is absorbing or supplying power. - Answers absorbing, like a load
If the power is negative, the element is absorbing or supplying power. - Answers supplying, like a
generator.
The RMS value of v(t) = Vmaxcos(wt + theta) is given by: - Answers Vmax / 2^0.5
For balanced wye-delta loads, Z delta = ? - Answers Z delta = 3Zy
For delta transformers, Vphase = ? - Answers V line to line. There is no neutral
In wye circuits, Phase = ? - Answers V line to neutral voltage
Step-down transformers - Answers Wye-delta transformers are frequently used as this.
current magnitude - Answers I_M = rad(2)I_rms
Complex Power (VA) - Answers S = V_rms x I*_rms;
S = P + jQ
the rating of power equipment is described by the apparent power, S, also measured in volt-amperes
P = real power
Q = reactive power
In this circuit, the current lags the applied voltage - Answers inductive
In this circuit, the current leads the applied voltage - Answers capacitive
Resistor real power equation - Answers S_R = V_R x I*
Capacitive reactive power [negative] equation - Answers S_C = V_C x I*
Voltage source complex power equation - Answers S_S = V_S x I*
Voltage regulation - Answers The difference between the magnitudes of the voltage at the load
terminals for the no-load (V_no-load) and (full) load conditions divided by the load voltage (V_load)
magnitude
Voltage regulation generalizations - Answers Typically, the voltage regulation should be less than
10%.
Overvoltage in no-load condition must be less than 5%.
The voltage drop in full load condition should not be more than -5%.
Loads - Answers Are represented by an impedance
Z = V_load / I_load = R + jX
Lagging - Answers The phase angle is positive if the load power factor is?
Leading - Answers The phase angle is negative is the load power factor is?
Low power factor - Answers This requires more rms current for the same load power which results in
greater utility transmission losses in the power lines.
S_load = V_load x I*_load = V_load x I_load x e^(+-jtheta_load) : (+) sign is used if the pf is? - Answers
Lagging
S_load = V_load x I*_load = V_load x I_load x e^(+-jtheta_load) : (-) sign is used if the pf is? - Answers
Leading
power factor is lagging if circuit is - Answers inductive
power factor is leading if circuit is - Answers capacitive
balanced three-phase system, each voltage source: - Answers has the same magnitude (V_M) and
frequency (w), and each is 120 degrees out-of-phase with the other two
A balanced three-phase circuit is one in which the loads are such that the _____ produced by the
________ are also balanced. - Answers currents, voltages
sum of the balanced voltages and the sum of the balanced currents in a three-phase system -
Answers equal zero
total instantaneous power equation - Answers p_T(t) = 3V_rms x I_rms cos(theta)
The total three-phase complex power is - Answers three times the complex power of any of the
phases
S_T = S_A + S_B + S_C = 3S_1
phasor voltage expressions of a wye-connected generator - Answers V_an = V_rms angle delta
V_bn = V_rms angle delta - 120 degrees
V_cn = V_rms angle delta - 240 degrees
phase voltage - Answers V_P is the phase voltage magnitude between the phase conductors and
neutral and is called the line to neutral voltage
If the power is positive, the element is absorbing or supplying power. - Answers absorbing, like a load
If the power is negative, the element is absorbing or supplying power. - Answers supplying, like a
generator.
The RMS value of v(t) = Vmaxcos(wt + theta) is given by: - Answers Vmax / 2^0.5
For balanced wye-delta loads, Z delta = ? - Answers Z delta = 3Zy
For delta transformers, Vphase = ? - Answers V line to line. There is no neutral
In wye circuits, Phase = ? - Answers V line to neutral voltage
Step-down transformers - Answers Wye-delta transformers are frequently used as this.
current magnitude - Answers I_M = rad(2)I_rms
Complex Power (VA) - Answers S = V_rms x I*_rms;
S = P + jQ
the rating of power equipment is described by the apparent power, S, also measured in volt-amperes
P = real power
Q = reactive power
In this circuit, the current lags the applied voltage - Answers inductive
In this circuit, the current leads the applied voltage - Answers capacitive
Resistor real power equation - Answers S_R = V_R x I*
Capacitive reactive power [negative] equation - Answers S_C = V_C x I*
Voltage source complex power equation - Answers S_S = V_S x I*
Voltage regulation - Answers The difference between the magnitudes of the voltage at the load
terminals for the no-load (V_no-load) and (full) load conditions divided by the load voltage (V_load)
magnitude
Voltage regulation generalizations - Answers Typically, the voltage regulation should be less than
10%.
Overvoltage in no-load condition must be less than 5%.
The voltage drop in full load condition should not be more than -5%.
Loads - Answers Are represented by an impedance
Z = V_load / I_load = R + jX
Lagging - Answers The phase angle is positive if the load power factor is?
Leading - Answers The phase angle is negative is the load power factor is?
Low power factor - Answers This requires more rms current for the same load power which results in
greater utility transmission losses in the power lines.
S_load = V_load x I*_load = V_load x I_load x e^(+-jtheta_load) : (+) sign is used if the pf is? - Answers
Lagging
S_load = V_load x I*_load = V_load x I_load x e^(+-jtheta_load) : (-) sign is used if the pf is? - Answers
Leading
power factor is lagging if circuit is - Answers inductive
power factor is leading if circuit is - Answers capacitive
balanced three-phase system, each voltage source: - Answers has the same magnitude (V_M) and
frequency (w), and each is 120 degrees out-of-phase with the other two
A balanced three-phase circuit is one in which the loads are such that the _____ produced by the
________ are also balanced. - Answers currents, voltages
sum of the balanced voltages and the sum of the balanced currents in a three-phase system -
Answers equal zero
total instantaneous power equation - Answers p_T(t) = 3V_rms x I_rms cos(theta)
The total three-phase complex power is - Answers three times the complex power of any of the
phases
S_T = S_A + S_B + S_C = 3S_1
phasor voltage expressions of a wye-connected generator - Answers V_an = V_rms angle delta
V_bn = V_rms angle delta - 120 degrees
V_cn = V_rms angle delta - 240 degrees
phase voltage - Answers V_P is the phase voltage magnitude between the phase conductors and
neutral and is called the line to neutral voltage
