REGISTERED ELECTRICAL ENGINEERS Pre-Board Examination ‘Sunday, August 26, 2007 8:00 am, ~ 12:00 nn. ELECTRICAL ENGINEERING PROFESSIONAL SUBJECTS 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 tne answer sheet provided. STRICTLY NO ERASURES ALLOWED. Use pencil No. 2 only. MULTIPLE CHOICE: 1. AG v car radio draws a current of 6.5 A. What resistance in ohms must be connected in series with it to operate it in a car with a 12 v battery? A 0,947 B. 0,969 ¢,0.923 D, 0.984 2. ta certain conductor has an area of 336,400 cmils, what is the radius of this conductor in om? ‘A. 0.663, B.0.810 ©.0.737 D. 0.921 3. A S-phase circuit 60 HZ, 230 XV transposed transmission line is composed af two 1,272 MCM 54/19 conductors per phase with horizontal configuration. The bundle conductors are 60 cm in distance While phase spacing between the centers of the bundle is 10 meters. If the GMR of the ACSR Conductors is 0.0466 ft, find the inductive reactance in ohmJ/km/phase of the transmission line? A. 0.3775 B. 0.3398, C.0.3628, D. 0.3964 4. What are the two elements in a series circuit connection having a current and voltage of (600t - 53.4*) A and v= 150 sin (500t + 10°) v? A. R=8.8Q andl = 35 mH B. R=6.3Q0 andl =25mH 13,42 sin 5 Qand L = 30 mH = 5 QandL=20mH po R R 5.A.3® Induction motor is rated 240 v, 180 A, 0707 pf. What size of capacitor in KVAR must be placed Parallel with the circuit to improve the pf, to 95% lagging? ANTA B41. C242 D296 6. A 230 v (line to neutral), S-phase is connected to three 10 resistance loads with both source and load in wye configuration. Determine the current in phase B. A-115-j19.9A C.-11.5 +] 19.94 B.11.5+) 199A D.115-j19.9A 7. Given the following séts of symmetrical components, determine the phase current for phase B. Im=tat7Sdeg |= tat 1Sdeg — Ie= 1 at (-45 deg) ‘A. 0.259 + 0.968 C.1,932 +f0. 518 B. 0.516 +} 1.931 D. 1414+] 1.414 &. Three resistors of 3,6, and Z ohms, respectively are connected in parallel across a constant current source of 10 A. Find the value of Z if this resistor draws 2 A current? A3 Bb o4 De 8. A 120 cm long conductor is carying a current of 3.2 A and is situated at right angles to a field with flux density of 0.857. Calculate the force on the conductor. : A, 3.2640 N) B.3.3048.N C. 3.1396 N 0.3.5477N 10. A series RLC circuit has elements R = 50 0, L = 8 mH and C = 2.22 microfarads, What is the equivalent impedance of the circuit ifthe frequency is 796 HZ? A.60 +j500 B. 50+) 1300 C.50-] 500 D.50-j 1300 14. The voltage applied across the resistor was reduced by 50%. The power consumed by the resistor will be reduced by %. ATS B, 50 0.25 D. 100REGISTERED ELECTRICAL ENGINEERS Pre-Board Examination Sunday, August 26, 2007 8:00 am, ~ 12:00 nun. ELECTRICAL ENGINEERING PROFESSIONAL SUBJECTS 12, A140 v de motor draws a current of 30 A and is located 500 ft from the power source. What is the supply voitage if the diameter of copper wire is 0.25 inch? A119 B17 6.121 D145 13, Find the value of an impedance which requires — 1,540 vars at 220 v rms and 10 A sms, A.17.40~j 15.00 €.17.09 = 15.39 B. 16.82 -} 15.69 D.17.62-| 14.78 14. A balanced delta connected load of 4 ~ j 3 9 per phase is fed by a 380 v, 3-phase system. Find the reactive power in KVAR, A.52 B29 c.69 D.87 16. A transformer having a 360 turn primary winding takes 150 watts in power and *.4 A in ourrent at an input voltage of 230 v at no-load, Determine the no-load p.f. A. 0.606 B 0.866, ©. 0.466 D. 0.528 16. The phase currents in a wye connected, unbalanced load are |, = 44 —j 33, y = - 32 ~j 24 and l= = 40+) 25 A. What is the positive sequence current for phase A? A. 28-31 B.402+;/89 ©. 284) 31 D.408-j89 17. What is the complex expression for a given alternating current, i = 250 sin (ot ~ 25 deg)? A. 227 +] 108 B. 160~j75 ©, 227 =} 108 D. 160+) 75 18. A balanced three-phase wye connected source has Ven, = 220 v rms with 30 degrees angle. Using a positive phase sequence, determine Vo.? A. 490.5 + j 330 vims ©. 190.5~j 330 v ms B, -190.5 ~ 330 vrms D. ~| 381 vims 19. A 115 KV three-phase transposed transmission line Is composed of 2-ACSR 336,400 cmil, 30/7 ‘Orioie conductors per phase with horizontal configuration: Diz = 7 ft, Das = 7 ft, and Dys = 14 ft. The fine spacing is measured from the center of the bundled conductors. The distance between the ‘conductors of the bundle is 6 inches. The conductors have a diameter of 0.741 inch and a GMR of 0.02255 ft. Find the capacitance per phase for 20 km of the line in microfarads? ‘A. 0.2689 B. 0.2609 ©.0.1300 D. 0.2719 20, The effect of the dielectric is to ‘A. increase the capacitance C. increase the working voltage B. decrease the capacitance D. reduce the working voltage 21. A length of copper telephone line has a resistance of 24 ohms at 20 degree C. What is its resistance on hot summer day when its temperature rises to 36 degree G? A 2650 8.24.50 C.25.50 D.27.50 22. A balanced three-phase, wye-connected load of 150 kW takes a leading current of 100 A, when the line is 2,400 v, 60 HZ. What is the capacitance per phase? A.21 mF B21 uF 6. 205 mF D. 208 uF 23. An impedance Z; is in series to the two impedances Z; = 10 +ji0 © and Z, = 20 - | 30 0 that are connected parallel. What is the value of the impedance Z; in ohms that will produce resone'nt circuit? A134 B-ib4 c.j54 2. -j13.4 24. Find the current thru a 0.10 microfarad capacitor at t = 0 if the voltage across it is ~ 2 e raised to ~ 10 raised to 7 xtv, A, 200 mA, B,20mA C.2A D208REGISTERED ELECTRICAL ENGINEERS Pre-Board Examination Sunday, August 26, 2007 8:00 am, — 12:00 nin, ELECTRICAL ENGINEERING PROFESSIONAL SUBJECTS 25. What will happen to an insulating medium if subjected to a voltage more than the basic impulse insulation level? It will A, change its molecular structure ©. get punctured B. become magnetic D. melt 28, In a balanced three-phase system, the Y-coniected impedances are 10 ohins with 30 degrees angle. If Vec is equal to 416 v with 240 degrees angle, determine I,,, Assume that phase sequence is abe. A12+j208A B,208-j12A 6. 12-]208A —D. 20.8 +) 12 27. A transmission line cable consists of 26 strands of identical copper conductors, each 1.265 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 19 raised to = 8 ohm/meter, what is the resistance of the cable in ohms? A108 B. 5.39 c.113 D.8.68 28. A generator of 50 MVA, 4 kV, X’g = 25% and transformer of 50 MVA, 4.2 KV delta/115 kV wye grounded, operating on 3.8 KV tap where X", = 10%, are to be connected into a single equivalent reactance. What is the single equivalent reactance on a 100 MVA, 110 kV base? A [0.6867 pu B, j 0.6039 pu C. | 0.8663 pu D.}0.8241 pu 29. Two batteries are connected in series, one of 8 v, 2 KO and the other of 18 v3 kM. The combination suppiles a 7 kQ load. Determine the power dissipated in the 3 kQ battery. A.t2mw B.1.2mw C.120 D.12w 30. A three-phase transposed distribution line is designed with equilateral spacing of 12 ft Itis decided to build the line with horizontal spacing ( Djs = 2D42 = 2Dzs ). The conductors are transposed. What should be the spacing between adjacent conductors in order to obtain the same inductance as in the original design? A. 9.5056 B. 9.5246 ©. 9.643; 0, 3.6190 31. Sparking occurs when a load is switched off because the circuit has high A. capacitance B. inductance C. resistance D. impedance 22. Two lamps having luminous intensity of 250 and 300 candelas, respectively ate placed 100 m apart. Lamp A is placed 10 m above the ground while lamp B is placed 20 m above of the same level. What is the illumination at the center of the lamp posts at ground level? A. 0.0384 tux B. 0.0572 lux ©. 0.4522 lux D. 0.0188 lux 33, A short 230 kV transmission line has an impedance of 10 cis 80° Q. The sending end power is 150 MW at 230 kV and 82% power factor. What is the voltage at the other end? A-222.45 kV B. 223.45 kV C. 224.45 KV D. 225.45 KV 34, The highest speed attained by a de shunt motor is A. equal to infinity at rated flux B. higher than no load speed at rated flux C, equal to no load speed at rated flux 1D. lower than no toad speed at rated flux 85. A transformer is rated 500 kVA, 4,800/480 v, 60 HZ when it is operated as a conventional two winding transformer, This transformer is to be used as a 5.28/4.8 kV stepcown autotransformer in a power distribution system, In the autotransformer, what is the transformer rating when used in this manner? A. MVA, B. 6 MVA C.5.5MVA D.6.5 MYA,