Frage 1
Frage
Which of the following formulas can calculate power in an ac circuit?
Antworten
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P = V x I x pf
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P = V + I
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P = V x I
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P = V/R
Frage 2
Frage
What is the power produced by a 400v three phase system which delivers 25A at a power factor of 0.85
Frage 3
Frage
What is the power produced by a 400v three phase system which delivers 10A at a power factor of 0.7
Antworten
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4849.6W
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4.7kW
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5000W
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4700W
Frage 4
Frage
The power factor of an installation can be calculated from
Antworten
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Cosθ = Z/X
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Cosθ = X/Z
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Cosθ = KVA/KW
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Cosθ = KW/KVA
Frage 5
Frage
The power factor of an inductive load can be improved by?
Antworten
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Connecting a inductor across the load
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Connecting a resistor in parallel with the load
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Connecting a capacitor in series with the load
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Connecting a capacitor across the load (parallel)
Frage 6
Frage
The power factor of a load consisting of inductance and resistance can be calculated from
Antworten
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Cosθ = True Power/Apparent Power
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Cosθ = Apparent Power/ Reactive Power
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Cosθ = Reactive Power/True Power
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Cosθ = Apparent Power/True Power
Frage 7
Frage
The formula required to calculate the total power of a single phase inductive load supplied by an a.c. supply is
Antworten
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P = IV sinθ
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P = IV
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P = IV tanθ
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P = IV cosθ
Frage 8
Frage
If the W is 100 and the VA is 120 what would the power factor be
Frage 9
Frage
If the kW is 200 and the KVA is 400 what would the power factor be?
Frage 10
Frage
A single phase circuit draws a current of 21.7A from a 230 V circuit at a power factor of 0.4
What is the current drawn if the power factor is corrected to 0.85
Antworten
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18.4 A
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23.4 A
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10.21 A
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21.7 A
Frage 11
Frage
A circuit dissipates 2000 W at a power factor of 0.5 when connected to a 230 V ac supply. The current drawn from the supply is
Antworten
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17.8 A
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17.39 A
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4.3 A
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8.7 A
Frage 12
Frage
A circuit dissipates 1.5 kW at a power factor of 0.75 when connected to a 230V ac supply. The current drawn from the supply is
Frage 13
Frage
A three phase system gives the following readings
kVA =30 kW= 45
What is the power factor for the system
Frage 14
Frage
A three phase system gives the following readings
kW= 400 kVA = 500
What is the power factor for the system
Frage 15
Frage
What unit is reactive power measured in
Frage 16
Frage
What unit is apparent power measured in
Frage 17
Frage
What unit is true power measured in
Frage 18
Frage
Which component would cause the current and voltage to behave as above
Antworten
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resistor
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rectifier
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capacitor
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Inductor
Frage 19
Frage
Which component would cause the current and voltage to behave as above
Antworten
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Inductor
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capacitor
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resistor
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rectifier
Frage 20
Frage
Which component would cause the current and voltage to behave as above
Antworten
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Inductor
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capacitor
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resistor
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rectifier