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WorksheetsAC Theory and 3 Phase Power
Total questions: 50
Worksheet time: 25mins
The number of cycles per second.
wavelength
peak value
frequency
RMS
One full rotation of the generator, or one full sine wave
cycle
frequency
wavelength
signal
The distance the AC signal can travel in one cycle.
cycle
frequency
wavelength
signal
The effective value, this is the amount of voltage that will produce the same amount of power as a similar DC voltage.
cycle
frequency
RMS
signal
Value of the maximum positive or negative portion of the waveform
cycle
frequency
RMS
peak
Determine which type of waveform is in the picture.
sine
square
triangle
sawtooth
Determine which type of waveform is in the picture.
sine
square
triangle
sawtooth
Determine which type of waveform is in the picture.
sine
square
triangle
sawtooth
Determine which type of waveform is in the picture.
sine
square
triangle
sawtooth
The peak voltage is 220 Volts. Find the value of Vrms?
155.54 V
140.14 V
15.54 V
14 V
The peak voltage is 220 Volts. Find the value of Vave?
155.54 V
140.14 V
15.54 V
14 V
The RMS value can be considered as the DC component of the AC waveform.
TRUE
FALSE
The RMS value is not equal to the effective value.
TRUE
FALSE
The power factor can be expressed as ___________.
cosine theta
sine theta
secant theta
tangent theta
What is the unit of Apparent Power?
VA
WATTS
VAR
RAV
What is the unit of Real or True Power?
VA
WATTS
VAR
RAV
What is the unit of Reactive Power?
VA
WATTS
VAR
RAV
The rating of the transformer is usually expressed in ________.
VA
VAR
RAV
WATTS
The transformer can use DC for power transmission.
TRUE
FALSE
Transformer data:
N1 = 200 turns
N2 = 25 turns
V1 = 800 turns
Find V2?
100 V
10 V
50 V
25 V
N1/N2 is also called as ______________.
Transformer turns ratio
Current ratio
power ratio
reactance ratio
There are ____ requirements before a voltage can be induced.
4
3
2
1
Two sources of sine wave
generator
pulse width modulation
battery
diode
This device converts DC to AC.
inverter
converter
rectifier
filter
A process which convert DC to AC.
pulse width modulation
electromagnetism
piezo electric
seebeck effect
The angle between real power and apparent power is 36.87 degrees. Compute the power factor?
0.8
0.9
1.0
0.7
A 5 Ampere current flowing to the circuit from the source of 220 Volts AC. If the power factor is 0.8, find the value of Apparent Power S?
1,100 VA
880 VA
660 VA
300 VA
A 5 Ampere current flowing to the circuit from the source of 220 Volts AC. If the power factor is 0.8, find the value of Real Power P?
1,100 VA
880 VA
660 VA
300 VA
A 5 Ampere current flowing to the circuit from the source of 220 Volts AC. If the power factor is 0.8, find the value of Reactive Power Q?
1,100 VA
880 VA
660 VA
300 VA
The value of Real Power is 40 W and the reactive power is 30 VAR. Find the value of Apparent power S?
50 VA
25 VA
10 VA
35 VA
A ___________ transformer decrease the voltage from primary to secondary.
step-up
step-down
step change
automatic
A ___________ transformer increase the VOLTAGE from primary to secondary.
step-up
step-down
step change
automatic
The ratio between the Apparent power and Real Power is called ______________.
power factor
step factor
unit step
transformer factor
In STEP-UP transformer, what will happen to the CURRENT?
increase
decrease
no change
increase then decrease
In STEP-DOWN transformer, what will happen to the CURRENT?
increase
decrease
no change
increase then decrease
In PWM, the square wave uses the __________ value to mimic or imitate the sine waveform.
average
RMS
peak
wavelength
In a purely resistive circuit voltage and current will be ______________ and the values will be the same as in a DC circuit
in-phase
90 degrees out of phase
-90 degrees out of phase
The __________ converts mechanical energy to electrical energy.
generator
motor
transformer
boiler
The __________ converts ELECTRICAL energy to MECHANICAL energy.
generator
motor
transformer
boiler
In a WYE connected circuit, the LINE to LINE voltage is 380 Volts. Find the value of LINE to NEUTRAL?
220 V
110 V
440 V
55 V
In a WYE connected circuit, the LINE CURRENT 10 Ampere. Find the value of PHASE current?
10 A
1.73 A
7.13 A
5.78 A
In DELTA connected circuit, the phase voltage is 480 Volts. Find the value of Line to Line Voltage?
480 Volts
240 Volts
277 Volts
110 Volts
In DELTA connected circuit, the phase current is 10 Amperes. Find the value of Line current?
17.3 A
1.73 A
3.71 A
7.31 A
In WYE connected circuit, what terminals should be connected together to form a neutral connection?
4,5,6
1,2,3
2,4,6
1,3,5
In DELTA connected circuit, what terminals should be connected together to form LINE 1?
1 and 6
2 and 4
3 and 5
1 and 5
In DELTA connected circuit, what terminals should be connected together to form LINE 2?
2 and 6
2 and 4
2 and 5
1 and 5
In DELTA connected circuit, what terminals should be connected together to form LINE 3?
3 and 6
3 and 4
3 and 5
1 and 5
Select the 3 requirements in order to produce EMF or Voltage.
conductor
magnetic field
relative motion (mechanical rotation)
heat
Electromagnetic inductions states that a magnet can develop electricity while the electricity can develop magnet.
TRUE
FALSE
The repulsion exists between the magnetic field generated by the armature and the magnetic field generated by the field windings, resulting in a rotational force known as ___________.
torque
weight
drag force
aerodynamics
