WorksheetsChapter 5 - Transformer
Total questions: 10
Worksheet time: 10mins
A transformer is ...
a rotating machine
an electromechanical energy converter
an electromagnetic machine
AC-DC machine
The function of a transformer is to ...
raise and lower the apparent power levels
transfer DC voltage from the primary winding to the secondary winding
increase or decrease A.C voltage or A.C current levels
transform mechanical energy into electrical energy
The magnetic material for the core needs to be made of soft iron where its permeability is high
to reduce eddy current loss
to reduce hysteresis loss
to avoid fringing in the core
to reduce copper loss in the winding
A step up transformer has its primary winding to secondary winding ratio
Greater than 1
Equal to 1
Less than 1
Unknown
Primary winding of a transformer is determined by ...
which winding is nearer to the load
which winding is connected to the source
which winding has more turns
which side has the highest voltage
Insulators are put between core lamination ...
to prevent flux leaks to the neighboring steel sheet
to reduce the cross-sectional area of the core
to prevent short circuit in the transformer
to prevent rusting in the lamination
The electrical energy is transferred through the ... in a transformer.
electric field
rotor
air space
magnetic field
The winding wire is coated with varnish so that ...
it can reduce the heat in the transformer
it can reduce the hysteresis loss
it can prevent the wire from rusted
each turn of the winding is insulated from every other turn
Choose the correct statement:
The ratio of the secondary voltage to the primary voltage is equal to the ratio of the primary turn to the secondary turn
The ratio of the primary current to the secondary current is equal to the ratio of the primary voltage to the secondary voltage
The ratio of the primary apparent power to the secondary apparent power is equal to the ration of the primary voltage to the secondary voltage
The ratio of the secondary current to the primary current is equal to the ratio of the primary turn to the secondary turn
Choose the correct statement:
The efficiency of a transformer is the percentage of the ratio of its input power to the output power
The ratio of the input apparent power to the output apparent power is less than 1 for a practical transformer
The ratio of the number of turns in the secondary winding to the number of turn in the primary winding determine the type of the transformer
Copper loss is due to eddy current in the core
