Test
Know the effects of components
Este test tiene tiempo límite, así que se abre en el reproductor de siempre.
Preguntas del test (20)
1Which of the following formulas can calculate power in an ac circuit?
- AP = V x I x pf
- BP = V + I
- CP = V x I
- DP = V/R
2What is the power produced by a 400v three phase system which delivers 25A at a power factor of 0.85
- A14.72kW
- B6.23kW
- C10kW
- D14kW
- A14.72kW
3What is the power produced by a 400v three phase system which delivers 10A at a power factor of 0.7
- A4849.6W
- B4.7kW
- C5000W
- D4700W
4The power factor of an installation can be calculated from
- ACosθ = Z/X
- BCosθ = X/Z
- CCosθ = KVA/KW
- DCosθ = KW/KVA
5The power factor of an inductive load can be improved by?
- AConnecting a inductor across the load
- BConnecting a resistor in parallel with the load
- CConnecting a capacitor in series with the load
- DConnecting a capacitor across the load (parallel)
6The power factor of a load consisting of inductance and resistance can be calculated from
- ACosθ = True Power/Apparent Power
- BCosθ = Apparent Power/ Reactive Power
- CCosθ = Reactive Power/True Power
- DCosθ = Apparent Power/True Power
7The formula required to calculate the total power of a single phase inductive load supplied by an a.c. supply is
- AP = IV sinθ
- BP = IV
- CP = IV tanθ
- DP = IV cosθ
8If the W is 100 and the VA is 120 what would the power factor be
- A0.75
- B0.2
- C0.85
- D0.83
9If the kW is 200 and the KVA is 400 what would the power factor be?
- A0.6
- B0.7
- C0.8
- D0.5
10A 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- A18.4 A
- B23.4 A
- C10.21 A
- D21.7 A
11A 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
- A17.8 A
- B17.39 A
- C4.3 A
- D8.7 A
12A 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
- A7.8 A
- B9.2 A
- C6.5 A
- D8.7 A
13A three phase system gives the following readings
kVA =30 kW= 45
What is the power factor for the system- A0.67
- Bunity
- C1.5
- D0.8
14A three phase system gives the following readings
kW= 400 kVA = 500
What is the power factor for the system- A1.25
- Bunity
- C0.8
- D0.6
15What unit is reactive power measured in
- AkA
- BKVAr
- CkW
- DKVA
16What unit is apparent power measured in
- AkA
- BKVAr
- CkW
- DKVA
17What unit is true power measured in
- AKVAr
- BkA
- CkW
- DKVA
18Which component would cause the current and voltage to behave as above
- Aresistor
- Brectifier
- Ccapacitor
- DInductor
19Which component would cause the current and voltage to behave as above
- AInductor
- Bcapacitor
- Cresistor
- Drectifier
20Which component would cause the current and voltage to behave as above
- AInductor
- Bcapacitor
- Cresistor
- Drectifier
Información
- Descripción
- Leading and lagging circuits
- Autor
- Vito Martino
- Idioma
- English
- Visitas
- 834
- Etiquetas
- Valoración
- 4,0 de 5 · 1 valoración Valora este test