Test
Unit 36 Mock Exam
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Preguntas del test (19)
1An inductor of 300mH placed on a 60Hz network will have an inductive reactance of?
- A113Ω
- B100Ω
- C113097Ω
- D97Ω
2A capacitor of 90µF is placed on an electrical network of frequency 65 Hz. What is the value of capacitive reactance?
- A27Ω
- B27000000Ω
- C27000Ω
- D0.0027Ω
3What is the typical generation voltage at a power station?
- A25kV
- B125kV
- C11kV
- D33kV
4Where is the neutral connected on the secondary of a delta to star transformer?
- AThe end of every line
- BThe star point of the transformer
- CTo the middle of every winding
- DLeft floating
5What is the phase separation angle in a typical star system between phases?
- A100°
- B120°
- C360°
- D110°
6A voltage of 700V is applied to two resistors in series. A current of 2.8A flows. If one of the resistors is 150Ω what is the value of the other?
- A100Ω
- B50Ω
- C75Ω
- D124Ω
7What is the series impedance of a circuit where the resistance is 30Ω the inductive reactance is 70Ω and the capacitive reactance is 30Ω?
- A50Ω
- B65Ω
- C70Ω
- D40Ω
8If you have a star phase voltage of 135V what would the line voltage be?
- A234V
- B200V
- C78V
- D75V
9A 30kW lift motor is running at 0.95 power factor. Calculate the line current that is drawn from the supply when the voltage is 390V:
- A47A
- B40A
- C37A
- D50A
10What type of light fitting requires no control gear?
- AIncandescent
- BFluorescent
- CSodium Discharge
- DHigh pressure mercury
11Which type of protective device natively offers the functions of earth fault, residual current and short circuit protection?
- ARCBO
- BMCB
- CRCD
- DACB
12A light source of 300 Candela is placed 2.5m above a table. Calculate the illuminance at a point directly below the light fitting.
- A48 Lux
- B48 Lumens
- C120 Lux
- D120 Lumens
13The full load current of a transformer is 650A and the voltage is 400V between phases. Calculate the apparent power rating of the transformer.
- A450kVA
- B400kVA
- C180kVA
- D400kW
14In a TT system the means of earthing is provided by:
- ADistributor's earth supply
- BInstallation earth electrode
- CCombined neutral and earth
- DNone it is an earth free location
15The phase voltage supplied to a building is 270V. The building is given a 3 phase 3 wire supply. What voltage are available to work with?
- A270V and 468V
- B468V
- C270V, 468V and 135V
- D300V
- E300V and 500V
16Calculate the angle the current lags the voltage in a network where there is 30kW and 12kVAr on the network.
- A21.8°
- B18°
- C25°
- D26.7°
17A centre tapped to earth transformer has a voltage of 75V phase to earth. What would the full voltage available be?
- A150V
- B100V
- C37.5V
- D130V
18A 25kW load is being drawn from a supply at 350V. Calculate the power loss through the conductor if the resistance is measured at 0.3Ω.
- A1000W
- B1640W
- C1530W
- D2160W
19The potential difference between a cat and the earth is 1000V. If the resistance of the cat is measured at 250Ω what would the current flow to earth be?
- A10A
- B250000A
- C4V
- D4A
Información
- Descripción
- unknown JTL Unit 36 and 38 Revision Test sobre Unit 36 Mock Exam, creado por giannini.chambers el 22/04/2015.
- Autor
- giannini.chambers
- Idioma
- English
- Visitas
- 172
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