WorksheetsTransformer and Safety
Total questions: 20
Worksheet time: 10mins
A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When a 120 V is applied to the primary coil, what is the voltage in the secondary coil?
480V
30V
20V
450V
This picture is an example of a ________________.
Motor
Generator
Step-up transformer
Step-down transformer
the correct colour coding for the wiring of a plug would be
earth green and yellow / blue line / brown neutral
earth green and yellow / blue neutral / Red Phase
earth blue / neutral green and yellow / brown line
earth brown / neutral blue / line green and yellow
the purpose of earthing on electrical equipment is to
allow the appliance to work properly
to reduce the voltage to an acceptable level
to prevent you getting an electrical shock
increase the efficiency of the appliance
When a bird touches two wires of different voltage, it will get shocked.
true
false
It is a good idea to not plug too many things into one outlet, since there is a risk of overloading the circuit at that outlet.
true
false
What is the color code of neutral wire for single phase non-flexible cable?
Red
Brown
Black
Blue
Earthing is necessary to give protection against
Danger of electric shock
Voltage fluctuation
Overloading
High temperature of the conductors
Electrical symbol of a TRANSFORMER
A circuit breaker is
power factor correcting device
a device to neutralize the effect of transients
a waveform correcting device
a current interrupting device.
If a transformer reduces voltage, it is called a....................... transformer.
step left
step right
step up
step down
Calculate potential difference in the secondary coil based on the information given below.
Vp = 240 V
Np = 20
Ns = 125
Vs ?
1500
500
1000
2000
E.M.F Equation of the Transformer is _________.
E1 = 4.44 f N1 Øm , E2=4.44 f N2 Øm
E1= 4.44 f N1 Bm A , E2 = 4.44 f N2 BmA
E1= 4.44 N1 Øm/T , E2=4.44 N2 Øm/T
All of the above
None of the above
A Transformer______________.
Changes ac to DC
Changes dc to AC
Steps up or down DC Voltages & Current
Steps up or down AC Voltages & Current
Lamination of the transformer core is made of
Cast Iron
Silicon Steel
Aluminum
Cast Steel
A Step-Up Transformer which has 110/220 turns.What would happen if we replace it with 10/20 turns? (because Turns ratio would be same in both cases)
induced E.M.F wold be same
Induced E.M.F would be decreased
Induced E.M.F would be increased
None of the above
The rating of transformer may be expressed in ____________.
kW
KVA
KVAR
HORSE POWER
What will happen if the primary of a transformer is connected to D.C supply?
Transformer will operate with low efficiency
Transformer will operate with high efficiency
No effect
Transformer may start to smoke and burn
The path from a circuit to earth is called a ____.
ground
grounded
grounding conductor
grounding electrode
A grounding electrode conductor is connected between the ____.
grounding busbar and the grounding electrode
neutral busbar and the grounded busbar
grounding busbar and the neutral busbar
ungrounded electrode and the meter
