25550557

Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
E2
8:00 am – 12:00 noon
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SET A
INSTRUCTION: Select the correct answer for each of the following questions. Mark
only one answer for each item by shading the box corresponding to the letter of
your choice on the answer sheet provided.
STRICTLY NO ERASURES ALLOWED. Use pencil no. 1 only.
NOTE:
Whenever you come across a caret (^) sign, it means exponentiation.
Ex. x^2 means x2; (x+y)^(x-z) means
(x+y) raised to the (x-z). Pi=3.1416
MULTIPLE CHOICE
1. Find the impedance which requires 1549 VAR AT 230 V rms and 10 A rms.
A. 17.40 - j15 ohms
C. 17.09 - j15.39 ohms
B. 16.82 – j15.69 ohms
D. 17.62 – j14.78 ohms
2. For a series RLC circuit with elements R = 50 Ω, L = 8 mH and C = 2.22 μF.
What is the equivalent impedance of the circuit if its frequency is 796 Hz?
A. 50 – j50 ohms
C. 50 + j130 ohms
B. 50 + j50 ohms
D. 50 – j130 ohms
3. Find the current that will follow in a series circuit containing a 5 kohm
resistor, a 470 picoF capacitor, a 150- mH inductor, and a 0.001 microfarad if
the exciting voltage is 65 volts at 25kHz.
A. 6.32 +j8.46mA
C. 8.46+j6.22mA
B. 6.22-8.46mA
D. 8.46-j6.22mA
4. Two impedances, Z1=0.8+j5.6 and zZ2=8-j16 and the single phrase motor are
connected in parallel across 200 Vrms. 60Hz supply. The motor draws 5 kVA at
80% power factor lagging. Find the complex power of impedance Z2?
A. -1-j2kVA
C. 2+ j1kVA
B. 1-j2kVA
D. -2-j1kVA
5. What are the two elements in a series circuit connection having a current and
voltage i= 13.42 sin (500t-53.4degrees) A and v= 150sin (500t+10degrees) V?
A. R= 8.8 ohms and L=35mH
C. R= 6.3 ohms and L=25mH
B. R= 7.5 ohms and L=30mH
D. R= 5.0 ohms and L=20mH
6. The impedance Z3 in series to the two impedances Z1= 10+ j10 ohms and Z2= 20j30 ohms that are connected in parallel. What is the value of the impedance Z3
in ohms that will produce resonant circuit?
A. –j13.1
C. j13.1
B. j5.4
D. –j5.4
7. One hundred picofarad capacitor is connected in series with a coil having
inductance of 100μH and a resistance of 100 ohm. At what frequency will this
network have at unity pf.
A. 1.4 MHz
C. 1.8 MHz
B. 1.2 MHz
D. 1.6 MHz
8. A 125-F capacitor that has a n initial voltage of 25-V is charge with a
current that varies with time according to the equation i = t (t2+6.83)1/2.
Find the voltage across the capacitor at 1 s.
A. 26 V
C. 25 V
B. 20 V
D. 20.2 V
9. Find the current through a 0.1 microfarad capacitor at t = 0, if the voltage
across it is -2 e-10^7t V.
ELECTRICAL2/Page 1
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
E2
8:00 am – 12:00 noon
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 200 mA
B. 20 mA
SET A
C. 20 A
D. 2 A
10. A balanced three-phase wye-connected load
of 100 A, when the line is 2400 V, 60 Hz.
A. 21 Mf
C. 205
B. 21 μF
D. 205
of 150 kW takes a leading current
What is the capacitance per phase?
mF
μF
11. A balanced delta connected load of 4 – j3 ohms per phase is fed by a 380 V,
three-phase system. Find the reactive power.
A. 52 kVARS
C. 69 kVARS
B. 29 kVARS
D. 87 kVARS
12. The phase currents in a wye-connected unbalanced load are la – 44 – j33, lb =
-32 – j24, and lc = -40 + j25 A. What is the positive sequence current for
phase A?
A. -28 – j21 A
C. 28 – j31 A
B. 40.8 + j8.9 A
D. 40.8 – j8.9 A
13. A 240 V (line to neutral) three-phase source is connected to three 10 ohm
resistance loads with both source and load in the Y-configuration. Determine
the current in each phase
A. 22 A
C. 24 A
B. 20 A
D. 28A
14. A balanced three-phase wye connected source has using positive phase
sequence. Van = 220 V rms with 30 degrees angle. Determine Vbc.
A. 190.5 + j330 V
C. -190.5 – j330 V
B. 190.5 – j330 V
D. – j381 V
15. In a balanced three-phase system, the wye-connected impedances connected are
10 ohms with 30 degrees angle. If Vbc is equal to 416 V with 240 degrees
angle, determine Icn. Assume the phase sequence is abc.
A. 12 + j20.8 A
C. 12 – j20.8 A
B. 20.8 – j12 A
D. 20.8 + j12 A
16. Given the following phase currents, Ia = 3.5 + j3.5, Ib = 0 – j3 and Ic = -2.6
+ j1.6. determine the negative sequence current for phase A.
A. 0.333 + j0.678
C. 0.424 + j0.571
B. -0.333 – j0.678
D. -0.333 + j0.678
17. Given the following sets of symmetrical components currents, determine the
phase B current.
Current
Magnitude
Angle, degrees
Ia0
1.0
75
La1
1.0
15
La2
1.0
-45
A. 0.259 + j0.966
C. 1.932 + j0.518
B. 0.516 + j1.931
D. 1.414 + j1.414
18. A transformer having a 360 turn primary winding takes 150 W in power and 1.4
A in current at an input voltage of 230 volts. Determine the no-load power
factor.
A. 0.606
C. 0.466
B. 0.866
D. 0.523
19. A transformer when it is operated as a conventional two winding transformer
ELECTRICAL2/Page 2
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
E2
8:00 am – 12:00 noon
SET A
is rated 10 MVA, 12/1.2 kV, 60 Hz. Under these conditions, its series
resistance and reactance are given as 2% and 7% pu respectively. This
transformer is to be used as 13.2/12 kV step-down autotransformer in a power
distribution system. What is the transformer’s series impedance in pu in the
autotransformer connection?
A. 0.0017 + j0.0058
C. 0.0020 + j0.0070
B. 0.0022 + j0.00778
D. 0.0018 + j0.0064
20. A transformers rated 500 kVA, 4800/480 V, 60 Hz when operated as a
conventional two winding transformer is to be used as a 5.28/4.8 kV step down
autotransformer in power distribution system. In the autotransformer
connection, when is the transformer’s rating when used in this manner?
A. 5MVA
C. 5.5 MVA
B. 6MVA
D. 6.5 MVA
21. The open circuit and short circuit tests were performed on the primary side
of the 25 kVA, 7620/240, 60 Hz transformer and the following data were
obtained, open circuit test; Eoc = 7620 V, Ioc = 0.30 A and Poc = 500 W. Short
circuit test Esc = 450 V, Isc = 3.5 A and Psc = 220 W. Determine the shunt and
series impedances refer to the primary of the transformer.
A. 116 + j26 k & 17.97 + j130 
C. 112 + j22 k & 15.95 + j128 
B. 124 + j14 k & 21.85 + j134 
D. 120 + j10 k & 19.95 + j132 
22. An induction motor is rated 240 V, 150 A and 0.707 power factor. What is the
size of the capacitor in kVAR which must be place in parallel with the circuit
to improve the power factor to 95% lagging?
A. 17.1
C. 41.9
B. 24.3
D. 26.9
23. A transmission line cable consists of 26 strands of identical copper
conductor, each 1.255 mm in diameter. The length of the cable is 10 km but
because of the twist of the strands, the actual length of each conductor is
increased by 5%. If the resistivity of the copper is 1.72 x 10-8 ohm-meter,
what is the resistance of the cable in ohms?
A. 1.08
C. 1.13
B. 5.39
D. 5.66
24. A single-phase transmission line 90 km is made up of hard drawn copper 500
mils in diameter. If the resistivity of the hard drawn copper at 20°C is 1.72
x 10-8 ohm-meter. Determine the loop resistance at 20°C.
A. 0.1394 ohm/km
C. 0.546 ohm/km
B. 1.348 ohm/km
D. 0,434 ohm/km
25. A three-phase transposed distribution line is designed with equilateral of 12
ft. it is decided to build the line with horizontal spacing D31=2D12=2D23.
What should be the spacing between adjacent conductors in order to obtain the
same inductance as the original design?
A. 9. 5246 ft
C. 9.5066 ft
B. 9,6437 ft
D. 9.6198 ft
26. A 69 kV three phase transposed line is composed of one ACSR 336,400 cmil,
36/7 Linnet conductor per phase with a horizontal configuration of D12=5 ft,
D23= 5 ft and D23=10 ft. The conductors have diameter of 0.721 inch,
resistance of 0.306 ohm per mile and gmr of 0.0244 ft. What is the reactance
for 12 miles line.
A. 6 ohms
C. 4 ohms
B. 2 ohms
D. 8 ohms
ELECTRICAL2/Page 3
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
E2
8:00 am – 12:00 noon
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SET A
27. A single circuit, transposed overhead transmission line is composed of twoconductors per phase. The diameter of each conductor is 5 cm. the distance
between the center of the bundle is 5 m. What is the inductance per km per
phase of the line.
A. 0.4412 mH
C. 0.9323 mH
B. 0.9136 mH
D. 0.8825 mH
28. A three-phase circuit, 60 Hz, 230 kV transposed transmission line is composed
of two 1272 MCM, 54/19 conductors per phase with horizontal configuration. The
bundle spacing is 50 cm while phase spacing between the centers of the bundle
is 10 m. If the GMR of the ACSR conductors is 0.466 ft, find the inductive
reactance in ohm/km/phase of the transmission line?
A. 0.3775
C. 0.3628
B. 0.3398
D. 0.3964
29. A 115-kV three-phase transposed transmission line is composed of two ACSR
336,400 cmil, 36/7 Oricle conductors per phase with horizontal
configuration:D12=7 ft; D23= 7 ft and D13= 14 ft. The line spacing as measured
from the center of the bundled conductors is 6 inches. The conductors have a
diameter of 0.741 inch a GMR of 0.02265 ft. Find the capacitance per phase for
20 km of the line in microfarads.
A. 0.2889
C. 0.2300
B. 0.2609
D. 0.2719
30. A 75 kVA, 13.2 kV/240V delta-wye distribution transformer has a resistance of
1% pu and reactance of 8% pu. Wht is the transformer’s phase impedance
referred to the high voltage side?
A. 69.70 + j557.57ohms
C. 71.09 + j558.72 ohms
B. 69.95 + j543.63 ohms
D. 70.58 + j564.54 ohms
31. The per phase parameters for a 60 Hz, 200 km long transmission line are
R=2.07 Ω and L=310.8 mH and C=1.4774 μF. The transmission line supplies a 100
MW, wye connected load at 215 kV (line to line) and 0.9 power factor lagging.
Using nominal π model, determine the sending end voltage line to line.
A. 229 kV
C. 236 kV
B. 243 kV
D. 233 kV
32. A generator of 50 MVA, 4 kV, X”d=25% and a transformer of 50 MVA, 4kV
delta/115 kV wye-grounded operating on a 3.8 kV tap where Xt”=10% to be
connected into a single equivalent reactance. What is the single equivalent
reactance on a 100 MVA, 110-kV base?
A. j0.7667 pu
C. j0.8663 pu
B. j0.6039 pu
D. j0.8241 pu
33. The effect of the dielectric is to
A. increase the capacitance
C. decrease the capacitance
B. increase the working voltage D. reduce the working voltage
34. What will happen to an insulating medium if subjected to a voltage more than
its basic impulse insulation level? It will________.
A. change its molecular structure C. become magnetic
B. punctured
D. melt
35. If the certain conductor has an area of 336,400 cmils, what is the radius of
this conductor in cm?
A. 0.663
C. 0.737
B. 0.8310
D. 0.921
ELECTRICAL2/Page 4
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
E2
8:00 am – 12:00 noon
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SET A
36. A 110V dc motor draws current of 30A and is located 500ft from the power
source. What is the supply voltage if the diameter of the copper wire is 0.25
inch? Resistivity is 10.4 omhs-cmil per ft.
A. 119 V
C. 121 V
B. 117 V
D. 115 V
37. A series loop contains the following circuit elements in order a 8-volts
source, a 2k ohms resistor, a 3k ohm resistor, a 16-V source and a 7k ohm
resistor. What is the power absorbed by the 3k ohm resistor?
A. 12 mW
C. 0.12 W
B. 1.2 mW
D. 1.2 W
38. Three resistors 3, 4 and z ohms respectively are connected in parallel across
a constant current source of 10A. Find the value of z if the resistor draws 3
A current.
A. 6 ohms
C. 4 ohms
B. 2 ohms
D. 8 ohms
39. The voltage applied across the resistor was reduced by 50%. The power
consumed by resistor will reduced by?
A. 75
C. 25
B. 50
D. 100
40. A 6 V car radio draws a current of 6.5
connected in series with it to operate
A. 0.947
C.
B. 0.969
D.
A. What resistance in ohms must be
it in a car with a 12 V battery?
0.923
0.981
41. Three resistors R1=9k ohm, R2=9k ohm and R3=9k ohm are connected in parallel
across a 12-V power supply whose internal resistance is 1k ohm. How much
current is drawn from the source?
A. 6mA
C. 2.4 mA
B. 3mA
D. 1.2 mA
42. A 20-ohm resistor is connected in parallel with a variable resistor R. The
parallel combination is the connected in series with a 4-ohm resistor and
connected across a 240V source. Determine the minimum value of R if the power
of r is equal to the power taken by the 4-ohm resistor.
A. 7.95 ohms
C. 7.64 ohms
B. 8.40 ohms
D. 6.87 ohms
43. Two batteries are connected in parallel to feed a 12-ohm load. Battery A has
open circuit emf of 6.3V and internal resistance of 1.5 ohms. Battery B has
open circuit emf of 6V and an internal resistance of 2.1 ohms. What is the
load current?
A. 0.48 A
C. 0.44 A
B. 0.52 A
D. 0.56 A
43. The resistance of a length of copper wire is 2.6 ohms at 20deg. C. The temp
coefficient of resistance on a 20deg. C for copper is 0.0393. What is its
resistance at 75deg. C?
A. 3.670 ohms
C. 11.38 ohms
B. 3.162 ohms
D. 4.378 ohms
44. A length of a copper telephone line has a resistance of 24 ohms at 20deg. C.
What is the resistance on a hot summer day when its temp. raised to 36deg. C?
A. 26.5 ohms
C. 25.5 ohms
B. 24.5 ohms
D. 27.5 ohms
ELECTRICAL2/Page 5
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
E2
8:00 am – 12:00 noon
SET A
45. A certain copper wire has a resistance of 25 ohms at 10deg. C. Take the temp.
coefficient at 10deg. C to be 0.00409deg/C. What must be the maximum operating
temp.of the wire if its resistance is to increase by at most 20%?
A. 58.89
C. 59.24
B. 60.13
D. 59.25
46. A 120 cm long conductor is carrying a current of 1.2 A and is situated at
right angles to a field of flux density of 0.65T. Calculate the force on the
conductor.
A. 3.264 N
C. 1.348 N
B. 0.936 N
D. 1.587 N
47. State the force in pounds upon one side of a coil of 50 turns carrying a
current of 20 A if the real length of the coil is 12 inch and the flux density
is 25,000 lines per square inch. There are 4.448x10^5 dynes in a pound. The
conductors are at right angles to the flux.
A. 29.4
C. 27.9
B. 25.3
D. 26.6
48. What is the complex expression for a given alternating current i=250 sin(wt +
25deg.)?
A. 227 + j106
C. 227- j106
B. 160
- j75
D. 160+j75
49. The resistance of a length of copper wire is 2.6 ohms at 20˚C. The
temperature coefficient of resistance at 20˚C for copper is 0.003939/˚C. What
is its resistance at 75˚C.
A. 3.670 ohms
C. 11.38 ohms
B. 3.162 ohms
D. 4.378 ohms
50. Find the turn ratio of a transformer used to match a 14400 ohms load to a 400
ohms load.
A. 5:1
C. 6:1
B. 4:1
D. 36:1
51. Two 2-H coil are connected in series so that the mutual induction between
them is 0.2-H. find the total inductance when they are connected to be series
aiding.
A. 4.4 H
C. 3.6 H
B. 4 H
D. 16 H
52. A poles lap wound, dc machine has 728 active conductors running at 1800 rpm.
The flux per pole is 30 mWb. The armature current is 120A, what is the
electromagnetic power developed in the armature in kW?
A. 72.4
C. 65.5
B. 78.6
D. 62.4
53.
When one coil of magnetically coupled pair has a current of 5 amperes, the
resulting flux Φ11 = 0.4 mWb and flux Φ12 = 0.8 mWb respectively. If the
turns are N1 = 500 and N2 = 1500, find the mutual inductance.
A. 60 mH
C. 120mH
B. 80 mH
D. 240 mH
54.
The line currents in a delta connected load are Ia = 5 cis 0deg. Ib = 7.07
cis 225deg and Ic = 5 cis 90deg. Calculate the positive sequence components of
current for phase a.
A. 7.94 ∠224°
C. 5.57 ∠-15°
ELECTRICAL2/Page 6
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
B. 0
E2
8:00 am – 12:00 noon
SET A
D. 8.35 ∠-25°
55.
Power system has receiving current of 1.2 pu or current at the receiving
end and 0.6 pu voltage at the receiving end and 0.5 pu receiving power. When
the base current is 160 A and base voltage is 20 kV, what is ohmic value of the
resistance of the load?
A. 68.725
C. 35.827
B. 57.765
D. 43.375
56.
A resistance R and inductive reactance X are connected in parallel across
2.4 kV rms absorbs 288 kW at 0.8 power factor. Find the value of X in ohms.
A. 20
C. 30
B. 26.67
D. 45
57.
A 4 pole 60 Hz synchronous generator has a rating of 200 MVA, 0.8 power
factor lagging. The moment inertia of the rotor is 45,100 kg-m2. Find inertia
constant H.
A. 3 MJ/MVA
C. 4 MJ/MVA
B. 5 MJ/MVA
D. 6 MJ/MVA
58.
A 250 MW, 60 Hz turbine generator has a speed regulation of 5% based on its
own rating. The generator frequency decreases from 60 Hz to a steady state
value of 59.7 Hz. Determined the increase in the turbine power output.
A. 15 MW
C. 20 MW
B. 25 MW
D. 30 MW
59.
Two generating unit of 250 MW and 400 MW have governor speed regulation of
6% and 6.4% respectively from no-load to full load. They are operating in
parallel and share a load of 500 MW. Determined the load shared by each unit.
A. 200 MW & 300 MW
C. 220 MW & 280 MW
B. 225 MW & 275 MW
D. 240 MW & 260 MW
60.
The moment of inertia of a 100 MVA, 2 pole, 60Hz generator is 50x103 kg-m2.
Determined the angular momentum M for the machine.
A. 0.329 MJ rad/sec
C. 0.569 MJ rad/sec
B. 0.762 MJ rad/sec
D. 0.432 MJ rad/sec
61.
Two identical voltage source are
0.7+j2.4 ohm. V1 = 500 ∠16.26° volts
delivered by source 1.
A. 21 kW
B. 34 kW
connected by a line of impedance of
and V2 = 585 ∠0° volts. Find the real power
C. 28 kW
D. 56 kW
62.
A three phase transmission line is feeding from a 23/230-kV transformer at
its sending end. The line is supplying a 150 MVA at 0.8 pf load through a step
down transformer of 230/23 kV. The impedance of the line and transformers are
18+j60 ohms. The sending end transformer is energized at 23 kV. Determine the
tap setting for each transformer to maintain voltage at the load at 23 kV.
A. ts= 1.08 pu & tr= 0.926 pu
C. ts= 0.926 pu & tr= 1.08 pu
B. ts= 1.18 pu & tr= 0.916 pu
D. ts= 1.12 pu & tr= 0.912 pu
63.
A 100 kVA, 400 volts, wye connected salient pole synchronous generator runs
at full load and 80% power factor leading. If Xd= 2Xq= 1.1 ohms per phase and
Ra is negligible, calculate the voltage regulation.
A. -26.4%
C. -24.6%
B. -64.2%
D. -246%
64.
A 400-V, 3-phase, wye-connected round-rotor synchronous motor operates at
unity power factor while developing a power of 60 kW. If the synchronous
ELECTRICAL2/Page 7
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
E2
8:00 am – 12:00 noon
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SET A
reactance is 1 Ω per phase and the armature resistance is negligible, calculate
the induced voltage per phase.
A. 246.6 volts
C. 231 volts
B. 225.6 volts
D. 254.3 volts
65.
A two winding transformer rated 9 MVA, 120/90 volts, 60 Hz is to be
connected as autotransformer to supply a load at 120 volts from 210 volts
supply. What kVA load can be supplied without exceeding the current rating of
the windings.
A. 18
C. 21
B. 9
D. 24
66.
A 60 MVA, 69.3-kV, three phase synchronous generator has a synchronous
reactance of 15 ohms per phase and negligible armature resistance. The
generator is delivering rate power at 80% power factor lagging at rated
terminal voltage to an infinite busbar. If the generated emf is 36 kV per
phase, what is the maximum three phase power that the generator can deliver
before losing its synchronism?
A. 288 MW
C. 96 MW
B. 320 MW
D. 120 MW
67.
A small wind generator is to be designed to generate 50 kW of power at a
wind velocity of 25 mph. what is the approximate blade diameter?
A. 26 ft
C. 36 ft
B. 42 ft
D. 18 ft
68.
A single 60 Hz power line and a telephone line are parallel to each other.
The power line carries an rms current of 226 A. find the magnitude of voltage
per Km induced in the telephone line.
A. 8 V
C. 3 V
B. 6 V
D. 5V
69.
Calculate the positive sequence symmetrical components for the set of
unbalance voltage Va= 300∠-120° , Vb= 200∠90° , and 100∠-30°
A. 42.265 ∠-120°V
C.193.185∠-135°V
B. 86.947∠-120°V
D. 185.567∠-120°V
70.
The symmetrical components for the set of unbalance three phase currents
are: Iao= 3∠-30°,Ia1= 5∠-90°,Ia2= 4∠30° find the current at line b
A. 8.185∠42.216°
C. 4∠-30°
B. 8.185∠-102.216°
D. 4
71.
72.
Find the value of (1+a)/(1+a2)
A. 1∠120°
B. 3∠0°
C. 3∠180°
D. 1∠ − 120°
What is the equivalent of Van1
1
A. 𝑉𝑏𝑐∠90˚
C.
B.
D.
√3
1
𝑉𝑏𝑐∠120˚
√3
1
𝑉𝑏𝑐∠ − 90˚
√3
1
𝑉𝑏𝑐∠ − 120˚
√3
73.
In the three phase system, phase is on no load, phase b and c are shorted –
circuited to ground. The following current are given: Ib= 91.65∠160.9° and
In=91.65∠160.9°. Find the zero sequence current.
A. 20∠90°
C. 40∠90°
B. 60∠180°
D. 30∠180°
ELECTRICAL2/Page 8
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
E2
8:00 am – 12:00 noon
SET A
74.
A generator having a solid grounded neutral and rated 50 MVA, 30 kV has
X1=25%, X2=15%, and Xo=5%. What reactance must be placed in the generator
neutral to limit the fault currents for a bolted double line to ground fault to
that for a bolted 3-phase fault?
A. 2.4 ohms
C. 0.825 ohm
B. 1.8 ohms
D. 0.765 ohm
75.
A 4-pole, 60 Hz, 3-phase induction motor has a blocked rotor reactance of
0.5 ohm per phase and the rotor resistance of 0.1 ohm per phase. At what speed
will the motor develop maximum torque?
A. 1200 rpm
C. 1440 rpm
B. 1500 rpm
D. 1620 rpm
76.
A 10 Hp, 440 volts, 60 Hz, 3-phase, 6 pole, induction motor has 4% slip at
full load. What is the full load speed?
A. 1140 rpm
C. 1152 rpm
B. 1162 rpm
D. 1200 rpm
77.
A two winding transformer is rate 60 kVA, 240/1200 V, 60 Hz. When operated
as a conventional two winding transformer at rated load, 0.8 pf lagging, its
efficiency is 96%. This transformer is to be used as a 1440/1200 volts step
down transformer, find the new efficiency at 0.8pf.
A. 99.31%
C. 98.9%
B. 97.8%
D. 96.8%
78.
A 5 hp 4 pole, 60 Hz 3-phase induction motor with a wound rotor draws 4590
watts from the line. What is the speed of this motor when delivering 4.95 hp,
if the core loss is 250 watts, the stator copper loss is 390 watts, and the
friction and windage loss is 70 watts?
A. 1720 rpm
C. 1715 rpm
B. 1724 rpm
D. 1750 rpm
79.
A 25 hp 240 volts series motor takes 93 amperes when driving its rated load
at 800 rpm. The armature resistance is 0.12 ohm and the series field resistance
is 0.08 ohm. At what speed will the motor operate if the load is partially
removed so that the motor takes 31 ampere? Assume that the flux is reduced by
50% for a current drop 66 2/3 percent and that the brush drop is 2 volts at the
both loads.
A. 1690 rpm
C. 1230 rpm
B. 1580 rpm
D. 1604 rpm
80.
The power plant has a maximum demand of 100 MW and connected load of 160
MW. Annual generation of 500 GWH. Calculate the load factor.
A. 32%
C. 57%
B. 37%
D. 22%
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ELECTRICAL2/Page 9
Republic of the Philippines
Professional Regulation Commission
Board of Electrical Engineering
Electrical Engineering Board Examination
E2
8:00 am – 12:00 noon
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SET A
81.
The rated line current of a 230 volts shunt motor is 56 amp. If the field
circuit resistance is 230 ohms and the armature circuit resistance is 0.15
ohms. What is the starting resistance to limit the current at starting to 125%
of the full load armature current.
A. 3.2 ohms
C. 2.4 ohms
B. 3.8 ohms
D. 4.2 ohms
82.
The voltage across 20 micro-farad capacitor varies
vc=(10.75-1.5e-1000t) volts. What is the current through
millisecond?
A. 0.023 sec
B. 0.013 sec
with time as given by
capacitor after 1
C. 0.011 sec
D. 0.033 sec
83.
A 100 hp, 1750 rpm, 2300 volts, 3-phase motor draws 150 amp when started at
2300 volts. If the compensator is to be used, and 80% voltage tap is selected,
find the starting current.
A. 96 A
C. 120 A
B. 108 A
D. 75 A
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