Pretest 204, 20pec 20& 20TS 2045
Pretest 204, 20pec 20& 20TS 2045
Pretest 204, 20pec 20& 20TS 2045
a. 20 A b. 10 A c. 15 A d. 5 A
17. A general-purpose single-phase motor rated 0.5 hp has a current rating of 5A. What should be the setting of
the overload relay that is installed to protect the motor? Assume the service factor of the motor to be 1.0.
a. 5.75 A b. 5.5 A c. 5.0 A d. 6.25 A
18. A single enclosed raceway for conductors or cables.
a. Box b. Duct c. Cabinet d. Gutter
19. Type MI cables shall permitted for ________.
a. branch circuits b. feeder circuits c. services d. all of these
20. Generator neutral maybe connected in common, provided that the third harmonic content of the waveform
of each generator does NOT exceed _____.
a. 3 % b. 4 % c. 5 % d. 6 %
21. Enclosure for overcurrent devices shall be mounted in what position?
a. Horizontal b. Vertical c. Diagonal d. Any
22. To support conduit on a hollow block wall, use one of the following methods. Which one is this?
a. Machine screw b. Lag screw c. Toggle bolt d. Through bolt
23. As applied to lightning protection, an attachment to secure the conductor to the structure or building.
a. Bonder b. Stapler c. Support d. Fastener
24. The bottom of sign and outline lighting enclosures shall NOT be less than ______ above areas accessible to
vehicles.
a. 5,000 mm b. 4,800 mm c. 4,700 mm d. 4,900 mm
25. Circuits containing electric discharge lighting transformers exclusively shall NOT be rated in excess of
a. 20 A b. 30 A c. 15 A d. 40 A
26. Each resistance welder shall have an over current device rated or set at not more than ______ percent of
the conductor rating. a. 300 b. 250 c. 175 d. 150
27. The transformer's secondary open circuit voltage used in electric signs shall NOT exceed
a. 15 kV b. 20 kV c. 12 kV d. 10 kV
28. Conductors external to motors and controls in cranes and hoists shall NOT be smaller than ______.
a. 2.0 mm² b. 1.25 mm² c. 3.5 mm² d. 0.75 mm²
29. An overcurrent device rated or set at NOT more than ______ percent of the conductor rating shall protect
conductors that supply one or more motor-generator arc welders.
a. 300 b. 200 c. 150 d. 125
30. Which of the motor starters does not stress the motor winding severely?
a. Across the line starter c. Soft-start starter
b. Wye-delta starter d. Transformer-type starter
31. Conductors in open wiring on insulators shall be rigidly supported at intervals NOT exceeding _____.
a. 1,200 mm b. 1,500 mm c. 1,300 mm d. 1,400 mm
32. What is the minimum depth of clear working space in front of a switchboard rated at 4,160 volts, where
there are exposed energized parts on both sides of the workplace?
a. 1,000 mm b. 1,900 mm c. 1,600 mm d. 2,000 mm
33. A 2.0 mm² TW copper conductor has an ampacity equal to _______.
a. 20 A b. 10 A c. 15 A d. 25 A
34. Rigid metal conduit shall be firmly fastened within _______of each outlet box.
a. 800 mm b. 900 mm c. 760 mm d. 600 mm
35. Type TW conductors have a maximum operating temperature of ______.
a. 75°C b. 50°C c. 60°C d. 90°C
36. Which of the following statements is NOT correct?
a. The use of an inductive ballast for fluorescent lamps is usually because it is the most efficient.
b. Lighting fixtures having exposed ballasts shall be so installed that they will not be in contact
with combustible materials
c. A ballast which incorporates an autotransformer to raise the voltage to more than 300 V shall
34. The standard method of controlling the output voltage of a 440-V, 60 Hz AC generator is accomplished by
adjusting the
a. number of poles c. alternator's field excitation
b. prime mover speed d. load on the alternator
35. How do you call the power lost in heat in the windings due to the flow of current through the copper
windings?
a. Hysteresis loss b. Copper loss c. Eddy current loss d. Stray load loss
36. What is the purpose of staggering brushes in a dc machine?
a. To reduce chattering
b. To cover more area on the commutator for more power
c. To even out the load
d. To prevent the uneven wear on the commutator
37. A 2-pole ac generator is running at 1,500 rpm. What is the frequency?
a. 25 Hz b. 60 Hz c. 50 Hz d. None of these
38. When the mechanical load is removed, which of the following motors run at high speed?
a. Shunt motor b. Compound motor c. Synchronous motor d. Series motor
39. Three resistances of 10, 4 and 6 ohms respectively are connected across each other. If the 6-ohm resistor is
shorted, what is their equivalent resistance?
a. 1.9 ohms b. 0 –ohms c. 2.85 ohms d. 1.333 ohms
40. What is the purpose of the poles and winding in the generator?
a. To cut down the magnetic flux lines
b. To neutralized the effect of armature reaction
c. To produce magnetic flux lines
d. All of these
41. A single phase AC motor has a full load current of 30 A. The rating of the two fuses for line protection is
a. 60 A b. 100 A c. 30 A d. 90 A
42. A new fully charged lead-acid battery will measure ________
a. exactly 12 V b. more than 12 V c. below 12 V d. none of these
43. If the multiplier of the resistor is a silver color, the ohmic value of the resistor is expected to be ___.
a. greater than 1 ohm b. less than 1 ohm c. either A or B d. neither A or B
44. What is the amperage of a 240-V , 3 phase feeder circuit supplying a total load of 128,000 VA?
a. 533 A b. 256 A c. 178 A d. 308 A
45. The resistance of a conductor, when its temperature is increased,
a. remains constant b. varies c. increases d. decreases
46. A transformer has a voltage ratio of 1:2, what is the current ratio equal to?
a. 2:1 b. 1:2 c. 1:4 d. 4:1
47. Which of the following is a preferred test used to check switchgear insulation?
a. dc high potential test c. ac high potential test
b. Megohmmeter test d. Variety loop test
48. Three 10-ohm resistors are connected in wye configuration. What will be the ohmmeter reading if the
terminals of the meter are connected between any two-line terminals of the wye connection?
a. 12 ohms b. 5 ohms c. 30 ohms d. 20 ohms
49. Short circuit test on transformer is used to determine _______.
a. transformation ratio
b. equivalent parameters on the high side
c. polarity of transformer terminals
d. all of these
50. Which of the following parts of an ac motor corresponds to the armature dc motor?
a. Field coils b. Rotor c. Stator d. Armature