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WorksheetsQB07SERFMJH6
Total questions: 100
Worksheet time: 1hrs 19mins
Why is it that slip rings are sometimes fitted on dc generators?
To apply excitation to the field
To supply ac from the machine
To convert the internal ac to dc
To supply more current
The temperature of the shunt field motor increased from 20°C to 30°C after 3 hours of operation. This increase in temperatures produces what effect on the behavior of the motor?
It will slow down due to decrease in the field current
It will have no effect
It will slow down the motor due to increase of field circuit resistance
It will speed up the motor due to decrease in the field current
Electron flow produced by means of applying a pressure to a material is called _____.
Electrochemistry
Thermoelectricity
Piezoelectricity
Photo conduction
A coil of wire placed in the armature core used to fill up the vacant slots but which is not connected to the armature windings.
Damping coil
Auxiliary coil
Dummy coil
Compensating coil
Which one is the most commonly used cell?
Silver-zinc
Lead-acid
Nickel-iron
Lithium
Which instrument is the most sensitive?
Permanent magnet moving coil
Dynamometer
Moving iron
Hot iron
The shunt of an ammeter is made from
copper
silver
manganese
manganin
The direction of rotation of a capacitor-start induction motor can be reversed by reversing
the starting winding leads
the running winding leads
either the starting winding leads or the running winding leads
neither the starting winding leads or the running winding leads
A three-phase load is balanced if all three phases have the same
Impedance
power factor
both impedance and power factor
resistance
PVC is a widely used insulation or jacketing on communication wires control cable, bell wire, building wire, appliance cord, etc. What do you mean by PVC?
Propylene chloride
Polyethylene chloride
Polyester chloride
Polyvinyl chloride
An electrical timer switch for lighting is normally connected in ____ with the lighting circuit being controlled.
tandem
sequence
series
parallel
When using Ohm's law IR would solve for ____.
amperage
resistance
electrical power
voltage
Alternator voltage can be increased by ____.
decreasing the prime mover speed
increasing the field circuit rheostat
increasing the prime mover speed
increasing the armature resistance
Unit of electrical current flow.
Ampere
Coulomb
Weber
Volt
International ohm is defines in terms of resistance of
a cube of carbon
a column of mercury
a cube of copper
a unit length of metal wire
At what percentage speed from rated will a centrifugal switch opens in a split-phase induction motor when started?
75%
50%
100%
60%
The ratio of KW to KVA is called
plarit factor
utilization factor
factor of safety
power factor
Counter emf is measured in
amps
volts
ohms
ampere-turns
A fluorescent lamp unit connected to a 110-V ac line takes 1.20 A and requires 110 W power. What is its power factor?
0.9
0.833
0.866
0.8
An electric heater uses 20 kW-hr in 8 hours. If the voltage across the heater is 240 volts. What is the heater resistance?
25 Ω
83 Ω
23 Ω
12 Ω
A rheostat is used to regulate the current in a circuit by
varying the voltage of the circuit
varying the power factor of the circuit
varying the resistance of the circuit
all of these
Ohm's law is applicable to
electric arcs
gas discharge lamp
rectifying devices
none of these
Capacitors are used to ____.
filter ac currents and pass dc currents
filter ac and dc currents
filter dc currents and pass ac currents
pass ac and dc currents
In a series circuit, the total resistance is _______.
the sum of the reciprocals of all resistances
the average of all resistances
the sum of all reistances
smaller than the smallest resistance
The hot resistance of a 230-V incandescent lamp is 300 ohms. What current is required to operate the lamp?
0.85 A
0.77 A
1.30 A
0.74 A
What voltage would be required to produce a flow of 10 A through resistance of 12 ohms?
125 V
122 V
121 V
120 V
The advantage of a wye-connected system is that _____.
the line currents and phase currents are equal
it is easy to troubleshoot due to it's a simple arrangement
two voltages can be used
none of these
An ac circuit has a resistance of 4 ohms and a reactance of 3 ohms. What is the impedance?
7 ohms
5 ohms
12 ohms
8 ohms
In a shunt-wound generator the rheostat is connected
in parallel with the field
acrossthe line
in series with the field
none of these
How many coils are there in a megger?
Two
Four
One
Three
Washing machines usually uses what type of motor?
Hysteresis motor
Compound motor
Shaped-pole motor
Resistance split-phase motor
The number of cycles of an arc voltage is known as
frequency
wave form
phase angle
half mode
One joule of electrical energy is equivalent to _____.
one watt-second
one watt-minute
one kilowatt-hour
one watt per second
Type of overload that contains a solder pot.
Bimetallic
Metallic
Melting alloy
Magnetic
A synchronous motor is excited with
an ac current
a dc current
a combination of ac and dc currents
any current
A cell supplies a load current of 0.5 A for a period of 20 hours until its terminal voltage falls to an unacceptable level. How long it could be expected to supply a current of 100 mA
50 hours
100 hour
60 hours
70 hours
The physical of a resistor that determines its ability to dissipate heat is rated in
amperes
ohms
volts
watts
A 3-ohm resistor and a 6-ohm resistor are connected in series across a dc supply. If the voltage drop across the 3-ohm resistor is 4 V, what is the voltage of the supply?
6 volts
8 volts
18 volts
12 volts
Solutions that are used in batteries are called
pastes
catalyst
compounds
electrolytes
Lubrication is never used on
a commutator
a knife switch
a cutting die when threading
wire being pulled into a conduit
In a dc generator, the purpose of the commutator is to ____.
rectify armature current
convert magnetic lines of force to flux
keep a constant voltage
keep a constant amperage
If an atom has less than 4 valence electrons, the material is
an insulator
a semi-conductor
a super conductor
a conductor
Insulators are commonly made from _____.
mica
porcelain
ceramic
all of these
A battery is a group of cells connected in
parallel
series-parallel
series
all of these
Another name for capacitance to ground.
Dielectric capacitance
Image capacitance
Skin capacitance
Stray capacitance
What is the internal resistance of an ideal current source?
Low
Negative
High
Zero
Which of the following is a requirement to induce a voltage and current in a wire?
A magnetic field
A conductor in a closed circuit
Motion between magnetic field and conductor in a closed circuit
All of these
Resistance commonly used in power circuits.
Carbon composition
Wire wound resistors
Deposited film resistors
Etched circuit resistors
When selecting the size of wire to be used in a circuit, the most important term to consider is the
resistance of the circuit
amperage of the circuit
voltage of the circuit
amount of wire to be used
How can a short circuit be detected?
By using an ohmmeter
By using a megger
By using an oscilloscope
By using an ammeter
Sheet metal troughs with hinged or removable covers for housing and protecting electric wires and cables and which conductors are laid in place after this object has been installed as a complete system.
Wireways
Busways
Cable trays
Non-metallic extensions
The minimum size of branch circuit capacity to supply laundry receptacle outlets shall be ____.
20 A
15 A
25 A
30 A
The grounding electrode conductor shall be ____.
copper
copper-clad-aluminum
aluminum
all of these
Conductors in open wiring on insulators shall be rigidly supported within ____ from a top or splice.
200 mm
100 mm
250 mm
150 mm
Main and equipment bonding jumper shall be made from ___.
copper
aluminum
both aluminum and copper
neither aluminum or copper
Which of the following statements is NOT one of the primary objective of the Philippine Electrical Code?
To establish electrical work standards
To establish basic material qualities
To ensure safety in using electricity
None of these
Connection between conductive or inductive metal object in an element of a lightning protection system to accomplish electrical continuity.
Connectors
Interlink
Counterpoise
Bonding
The minimum insulation level for neutral conductors of solidly grounded system shall be ____.
500 V
300 V
600 V
750 V
Flexible cords used in locations where there is a lot of flying flint or fibers shall comply with following EXCEPT one.Which one of this?
It shall be approved for use in locations which are vapor-filled
It shall contain in addition to the conductors, a grounding conductor
It shall be offtight approved for extra hard usage
It shall be provided with suitable seal to prevent the entrance of dust
For class II lightning materials, the minimum diameter of a solid copper air terminal shall be ___.
15.9 mm
12.7 mm
10.5 mm
9.5 mm
Art 1.10.2 of PEC 1 requires working spaces for equipment operating 600 V nominal or less to ground. This is required for live parts on the other side, like concrete, brick or tile walls and shall be considered as grounded. What is this minimum distance for condition 2?
1 300 mm
1 400 mm
1 200 mm
1 100 mm
Surge of unidirectional polarity.
Skin effect
Corona
Flashover
Impulse
Auxiliary gutter shall be supported through out it entire length at intervals ____
1, 500 mm
1, 800 mm
1, 200 mm
1, 600 mm
When installing cables or raceway type wiring method parallel to the framing members such as joists; refers or studs, the cable or raceway shall be installed and supported so that the nearest outside surface of the cable or raceway is NOT less than a certain distance from the nearest edge of the framing member. What is the distance?
20 mm
30 mm
10 mm
50 mm
Mats of insulating rubber or other suitable floor insulation shall be provided for the operator where the voltage to ground exceeds ______
150 V
100 V
250 V
120 V
A point at which the load of a given area is assumed to be concentrated.
Switchboard
Outlet
Panelboard
Load center
How many 20 A branch circuit shall be provided for all receptacle outlets for the small appliance load?
One or more
At least two
Only one
None of these
For a one family dwelling unit having an initial load of 10 kVA or more, the minimum service entrance capacity shall be _____
100 A
90 A
60 A
30 A
The workspace about electrical equipment shall be adequate to permit at least ___ degree opening of doors or hinged panels.
90
45
60
75
The multiplying factor for determining the size of branch circuit protection for non-time delay fuse is
300 %
175 %
250 %
175 %
Portable appliances equipped with proper cord and plug caps and NOT more than ____ maybe installed without an electrical permit.
1 200 VA
1 500 VA
1 000 VA
1 800 VA
Each transformer up to 600 V nominal shall be protected by an individual over current device on the primary side at not more than a certain percentage of the rated primary current of the transformer. What is this maximum percentage?
110%
125%
100%
140%
Tools and portable handlamps likely to be used in wet and conductive locations shall not be required to be grounded where supplied through an isolating transformer with an underground secondary of not more than _____.
100 V
150 V
50 V
60 V
What is the maximum fuse rating allowed by the code to protect a single phase motor that draws 20 A at full load against short circuit but at the same time will not fall at start?
30A
60A
50A
20A
The code has been approved and adopted by the Board, PRC. What does the acronym PRC stands for?
Philippine Registration Commission
Professional Regulation Commission
Philippine Regulation Commission
Professional Registration Commission
Which of the following is not a standard content of an electrical plan?
Location plan
Legend and general notes
Schedule of maintenance
Specifications
Conductors supplying one or more motor-compressors with or without additional loads shall have an ampacity not less than the sum of the rated load plus ___ percent of the highest motor-compressor rating in the group.
30
25
20
15
Which of the following conductors is NOT applicable on wet locations?
Type THHN
Type THW
Type RHW
Type THWN
Size 1.23 mm2 fixture wire has an ampacity of ___.
10A
8A
12A
9A
Motor A has a full load current of 8 A and motor B,10 A. What is the ampacity of the feeder conductor supplying this two motors?
9A
20.5A
18A
24.2A
For banks, general lighting load shall be computed at ____ per square meters of the floor area.
24
20
30
28
Cabinet and cutout boxes shall have an air space of at least ___ between any energized metal parts of enclosed fuses and the door.
20 mm
13 mm
25 mm
15 mm
Open wiring on insulators shall be permitted on systems of up to _____.
600 V
500 V
230 V
300 V
Conductors in concealed knob and tube wiring shall maintain a clearance of NOT less than ___ between conductors.
64 mm
50 mm
76 mm
100 mm
The minimum size of wire used in electrical wiring is the former number 14 AWG. Under the metric system shown in the PEC, the diameter is
2.0 mm
3.2 mm
1.6 mm
2.6 mm
Non-metallic sheathed cable shall be secured in place at intervals NOT exceeding _____.
1,300 mm
1,200 mm
1,500 mm
1,800 mm
The bending radius of type SNM cable shall NOT be less than ____ times the diameter of the cable.
3
4
5
6
The ampacity of type UF cable shall be of that ____ conductor.
60°F
140°C
60°C
75°C
Flexible metallic tubing shall NOT be used in lengths longer than _____.
2,00 mm
1,800 mm
1,900 mm
none of these
For each small appliance branch circuit, the feeder load shall be ____ per 20A circuit.
1,000 VA
1,200 VA
1,500 VA
1,800 VA
A lighting and appliance branch circuit panelboard is one having more than _____ percent of its over current device rated 30 A or less.
10
12
15
10
What is the nominal supply voltage specified by the Philippine Electrical Code for residential homes?
225 volts ac
230 volts ac
240 volts ac
220 volts ac
Non-metallic sheathed cable shall be supported within ____ from every cabinet, box or fitting.
150 mm
200 mm
250 mm
300 mm
Messenger supported wiring shall not be used in _____.
hoistways
multi-conductor underground feeder
metal clad cable
all of these
Heating cables shall be furnished complete with factory assembled non-heating leads at least ____ in lenght.
2,000 mm
2,200 mm
2,300 mm
2,100 mm
Rosettes shall be rated at 660 W, 250 V with a maximum current rating of _____.
6 A
10 A
4 A
12 A
When thermal overload relay are used for the protection of a three-phase induction motor, their primary purpose is to protect the motor in case of
short circuit between lines
reversal of phase sequence
high voltage
sustained overload
In type AC cable , all bends shall be made so that the cable will not be damage and the radius of the curve of the inner edge of any bend shall NOT be less than ____ times the diameter.
4
5
6
3
The electrical plans for residential house include the following items EXCEPT one. Which one is this?
Substation plan
Location plan
Floor plan showing location of service
Layout of wiring plan for general lighting and receptacle outlets
Temporary electrical power and lighting installations shall be permitted for a period not to exceed ______ for Christmas decorative lighting, carnivals and similar purposes.
100 days
120 days
90 days
60 days
