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Which of the following formulas can calculate power in an ac circuit?
P = V x I x pf
P = V + I
P = V x I
P = V/R
What is the power produced by a 400v three phase system which delivers 25A at a power factor of 0.85
14.72kW
6.23kW
10kW
14kW
What is the power produced by a 400v three phase system which delivers 10A at a power factor of 0.7
4849.6W
4.7kW
5000W
4700W
The power factor of an installation can be calculated from
Cosθ = Z/X
Cosθ = X/Z
Cosθ = KVA/KW
Cosθ = KW/KVA
The power factor of an inductive load can be improved by?
Connecting a inductor across the load
Connecting a resistor in parallel with the load
Connecting a capacitor in series with the load
Connecting a capacitor across the load (parallel)
The power factor of a load consisting of inductance and resistance can be calculated from
Cosθ = True Power/Apparent Power
Cosθ = Apparent Power/ Reactive Power
Cosθ = Reactive Power/True Power
Cosθ = Apparent Power/True Power
The formula required to calculate the total power of a single phase inductive load supplied by an a.c. supply is
P = IV sinθ
P = IV
P = IV tanθ
P = IV cosθ
If the W is 100 and the VA is 120 what would the power factor be
0.75
0.2
0.85
0.83
If the kW is 200 and the KVA is 400 what would the power factor be?
0.6
0.7
0.8
0.5
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
18.4 A
23.4 A
10.21 A
21.7 A
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
17.8 A
17.39 A
4.3 A
8.7 A
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
7.8 A
9.2 A
6.5 A
A three phase system gives the following readings kVA =30 kW= 45 What is the power factor for the system
0.67
unity
1.5
A three phase system gives the following readings kW= 400 kVA = 500 What is the power factor for the system
1.25
What unit is reactive power measured in
kA
KVAr
kW
KVA
What unit is apparent power measured in
What unit is true power measured in
Which component would cause the current and voltage to behave as above
resistor
rectifier
capacitor
Inductor
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