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WorksheetsPower supply system (RIT)
Total questions: 25
Worksheet time: 13mins
The diagram on the left shows the symbol of a
DC cell
DC battery
solar cell
LED
Identify the machine shown on the left.
generator
turbine
heat exchanger
boiler
Identify the symbol on the left.
AC source
AC booster
AC adaptor
AC motor
Which of the following is NOT true for AC supply?
The current flows in both direction
The current is changing all the time
The voltage is changing all the time
The frequency is changing all the time
Which of the following is NOT a power station in Singapore?
Tuas
Senoko
Pulau Seraya
Ayer Rajah
Identify the power station shown
Thermal
Nuclear
Hydroelectric
solar
In Singapore the fuel used in the thermal power station is
oil/gas
nuclear
biowaste
hydrogen
The equipment that drives the generator in the power station is the
turbine
furnace
condenser
chimney
Cooling of the steam in the power station is achieved using
sea water
cooling fan
oil
coolant
Identify the machine on the left
turbine
motor
cooling fan
circular blade
The output from the generator is stepped up for transmission by
transformer
amplifier
booster
relay
identify the equipment on the left
transformer
switchboard
condenser
power bank
Which one the following is NOT the advantage of transmitting at high voltage?
Reduce conductor size
Reduce voltage drop
Reduce power loss
reduce danger
Which of the following is NOT an advantage of underground transmission system?
minimise maintenance
suitable for densely populated areas
easy to maintain
reduce risk of lines surge
Which of the following is NOT an advantage of overhead transmission lines?
safe
easy to locate fault
fast to repair
cheap
Which cable connects between substation?
Feeder
service cable
Distributor
transmission lines
Which cable has different currents in different section of its length?
service cable
Feeder
Distributor
protective conductor
Heavy industries like oil refinery will receive their power at
66 kV
22 kV
6.6 kV
400 V
Medium and commercial buildings will likely receive power at
66 kV
22 kV
10 kV
6.6 kV
The configuration of power transformer winding connection for low voltage supply is
star/star
star/delta
delta/star
delta/delta
Extra low Voltage system has nominal voltage not exceeding
50 Vac
120 Vac
400 Vac
1000 Vac
For low voltage system the voltage between lines shall be more than 50 Vac but not exceed
230 Vac
400 Vac
600 Vac
1000 Vac
The supply authority is allowed to vary the consumer voltage by +/-
5%
4%
6%
3%
The lowest voltage for single phase supply that is acceptable in Singapore is
216.2 V
218.2 V
220 V
222.1 V
The highest acceptable voltage between the lines in a 3 phase 4 wire system is
424 V
420 V
414 V
410 V
