Principles of Engineering Exam:
Electrical Power Option-Updated 2026
135 Questions With Answers(Explained)
Three Identical complex 1-phase impedance loads are delta connected to make a
complex 3-phase load. Assuming balanced conditions, select the answer that
describes what would happen if the same load was wye connected instead
a) The load would draw the same amount of line current
b)The load would draw 1.73 times more line current
c) The load would draw 1.73 times less line current
d) The load would draw 3 times less line current - ANSWER✔️ZY = ZD/3.
Therefore with Ohm's law V=IR
In wye connected load:
I = Vp/ZY
In delta connected load
I = Vp/ZD/3 or I = 3Vp/ZD
Answer: D - The load would draw 3 times less current
Three Identical complex 1-phase impedance loads are wye connected to make a
complex 3-phase load. Assuming balanced conditions, select the answer that
describes what would happen if the same load was delta connected instead
a) The load would draw the same amount of apparent power
b) The load would draw 3 times more apparent power
c) The load would draw 1.73 times more apparent power
d) The load would draw 1.73 times less apparent power - ANSWER✔️Apparent
Power = 1.73 VI
In wye connected load:
I = Vp/ZY
In delta connected load
,I = Vp/ZD/3 or I = 3Vp/ZD
Line Current is 3 times more there for apparent power (S) will also be 3 times
more.
Answer: B - The load would draw 3 times more apparent power
A complex 3-phase wye connected load and complex 3-phase delta connected load
both have the same power rating and power factor. Select the statement that is true
a) Both loads will draw the same amount of line current
b) The wye connected load will draw 3 times more line current compared to the
delta connected load
c) The wye connected load will draw 3 times less line current compared to the
delta connected load
d) The wye connected load will draw 1.73 times less line current compared to the
delta connected load - ANSWER✔️Same power rating means they output the
same power.
wye power = delta power
Answer: A - Both loads will draw the same amount of line current
For a balanced and positive (ABC) sequence system, select the statement that is
true for wye connection
a) The phase voltage and line voltage are IN PHASE
b) The phase voltage LEADS the line voltage by 30 degrees
c) The phase voltage LAGS the line voltage by 30 degrees
d) The displacement angle between the phase voltage and line voltage depends on
the load - ANSWER✔️In Positive Wye connection:
Vphase Lags Vline by 30 degrees
Answer: C - The phase voltage LAGS the line voltage by 30 degrees
For a balanced and positive (ABC) sequence system, select the statement that is
true for a delta connection
, a) The phase current and line current are IN PHASE
b) The phase current LEADS the line current by 30 degrees
c) The Phase current LAGS the line current by 30 degrees
d) The displacement angle between the phase current and line current depends on
the load. - ANSWER✔️In positive Delta connection:
Iphase LEADS Iline by 30 degrees
Answer: B - The Phase current LEADS the line current by 30 degrees
For a Balanced and negative (ACB) sequence system, select the statement below
that is true for a wye connection.
a) The phase voltage and line voltage are IN PHASE
b) The phase voltage LEADS the line voltage by 30 degrees
c) The phase voltage LAGS the line voltage by 30 degrees
d) The displacement angle between the phase voltage and line voltage depends on
the load - ANSWER✔️In negative Wye connection:
Vphase Leads Vline by 30 degrees
Answer: B - The phase voltage LEADS the line voltage by 30 degrees
For a balanced and negative (ACB) sequence system, select the statement that is
true for a delta connection
a) The phase current and line current are IN PHASE
b) The phase current LEADS the line current by 30 degrees
c) The Phase current LAGS the line current by 30 degrees
d) The displacement angle between the phase current and line current depends on
the load. - ANSWER✔️In negative Delta connection:
Iphase LAGS Iline by 30 degrees
Answer: C - The Phase current LAGS the line current by 30 degrees
Select the statement below that is true in order to accurately measure the real
power drawn by an unbalanced 3-phase system.
Electrical Power Option-Updated 2026
135 Questions With Answers(Explained)
Three Identical complex 1-phase impedance loads are delta connected to make a
complex 3-phase load. Assuming balanced conditions, select the answer that
describes what would happen if the same load was wye connected instead
a) The load would draw the same amount of line current
b)The load would draw 1.73 times more line current
c) The load would draw 1.73 times less line current
d) The load would draw 3 times less line current - ANSWER✔️ZY = ZD/3.
Therefore with Ohm's law V=IR
In wye connected load:
I = Vp/ZY
In delta connected load
I = Vp/ZD/3 or I = 3Vp/ZD
Answer: D - The load would draw 3 times less current
Three Identical complex 1-phase impedance loads are wye connected to make a
complex 3-phase load. Assuming balanced conditions, select the answer that
describes what would happen if the same load was delta connected instead
a) The load would draw the same amount of apparent power
b) The load would draw 3 times more apparent power
c) The load would draw 1.73 times more apparent power
d) The load would draw 1.73 times less apparent power - ANSWER✔️Apparent
Power = 1.73 VI
In wye connected load:
I = Vp/ZY
In delta connected load
,I = Vp/ZD/3 or I = 3Vp/ZD
Line Current is 3 times more there for apparent power (S) will also be 3 times
more.
Answer: B - The load would draw 3 times more apparent power
A complex 3-phase wye connected load and complex 3-phase delta connected load
both have the same power rating and power factor. Select the statement that is true
a) Both loads will draw the same amount of line current
b) The wye connected load will draw 3 times more line current compared to the
delta connected load
c) The wye connected load will draw 3 times less line current compared to the
delta connected load
d) The wye connected load will draw 1.73 times less line current compared to the
delta connected load - ANSWER✔️Same power rating means they output the
same power.
wye power = delta power
Answer: A - Both loads will draw the same amount of line current
For a balanced and positive (ABC) sequence system, select the statement that is
true for wye connection
a) The phase voltage and line voltage are IN PHASE
b) The phase voltage LEADS the line voltage by 30 degrees
c) The phase voltage LAGS the line voltage by 30 degrees
d) The displacement angle between the phase voltage and line voltage depends on
the load - ANSWER✔️In Positive Wye connection:
Vphase Lags Vline by 30 degrees
Answer: C - The phase voltage LAGS the line voltage by 30 degrees
For a balanced and positive (ABC) sequence system, select the statement that is
true for a delta connection
, a) The phase current and line current are IN PHASE
b) The phase current LEADS the line current by 30 degrees
c) The Phase current LAGS the line current by 30 degrees
d) The displacement angle between the phase current and line current depends on
the load. - ANSWER✔️In positive Delta connection:
Iphase LEADS Iline by 30 degrees
Answer: B - The Phase current LEADS the line current by 30 degrees
For a Balanced and negative (ACB) sequence system, select the statement below
that is true for a wye connection.
a) The phase voltage and line voltage are IN PHASE
b) The phase voltage LEADS the line voltage by 30 degrees
c) The phase voltage LAGS the line voltage by 30 degrees
d) The displacement angle between the phase voltage and line voltage depends on
the load - ANSWER✔️In negative Wye connection:
Vphase Leads Vline by 30 degrees
Answer: B - The phase voltage LEADS the line voltage by 30 degrees
For a balanced and negative (ACB) sequence system, select the statement that is
true for a delta connection
a) The phase current and line current are IN PHASE
b) The phase current LEADS the line current by 30 degrees
c) The Phase current LAGS the line current by 30 degrees
d) The displacement angle between the phase current and line current depends on
the load. - ANSWER✔️In negative Delta connection:
Iphase LAGS Iline by 30 degrees
Answer: C - The Phase current LAGS the line current by 30 degrees
Select the statement below that is true in order to accurately measure the real
power drawn by an unbalanced 3-phase system.
