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WorksheetsTransformers
Total questions: 19
Worksheet time: 5hrs 45mins
Which of the following defines "transformer action"?
The transfer of energy from one circuit to another through electromagnetic induction
The transfer of energy from one circuit to another through electrostatic action
The development of counter electromotive force where a magnetic field cuts a coil
The development of a voltage across a coil as it cuts through a magnetic field
Which of the following is NOT a necessary element in a basic transformer?
A core
A primary winding
A secondary winding
A magnetic shield
What three materials are most commonly used for transformer cores?
Copper, soft iron, and air
Copper, soft iron, and steel
Air, copper, and steel
Air, soft iron, and steel
The two types of transformer cores most commonly used are the shell-core and the
I-core
E-core
hollow-core
laminated-core
What is the major difference between the primary and secondary windings of a transformer?
The primary has more turns than the secondary
The secondary has more insulation than the primary
The primary is connected to the source; the secondary is connected to the load
The primary is connected to the load; the secondary is connected to the source
What is the principal difference between a high-voltage transformer and a low-voltage transformer?
A high-voltage transformer has more turns of wire than a low-voltage transformer
A high-voltage transformer uses an air core, while a low-voltage transformer uses a shell-type core
A high-voltage transformer uses a shell-type core, while a low-voltage transformer uses an air core
A high-voltage transformer has more insulation between the layers of windings than does a low-voltage transformer
When the secondary of a transformer is NOT connected to a circuit, the transformer is said to be operating under which of the following conditions?
Uncoupled
No-load
Loaded
Open
What term applies to the current in the primary of a transformer that creates the magnetic field?
Exciting current
Primary current
Magnetizing current
Counter current
In the primary of a transformer, what opposes the current from the source?
The impedance
The forward emf
The counter emf
The exciting current
What is the source of the magnetic flux that develops secondary voltage in a transformer?
Primary emf
Secondary counter emf
Primary exciting current
Secondary exciting current
A transformer has a source voltage of 50 volts ac, with a turns ratio of 1:6. What is the voltage of the secondary winding?
150
300
500
600
A transformer has a 5:1 turns ratio; 20 volts are induced in the secondary. What is the primary voltage?
100 volts
50 volts
10 volts
4 volts
A transformer has thirty-five volts applied to its primary induces 105 volts in its secondary. The secondary is composed of 99 turns. What is the number of turns in the primary?
11 turns
22 turns
33 turns
44 turns
Power lost in realigning magnetic domains is known as what?
Copper loss
Eddy-current
Hysteresis loss
Leakage Loss
Power dissipated by the resistance of the windings is known as what?
Copper loss
Eddy-current
Hysteresis loss
Leakage loss
Power loss caused by random core currents is known as what?
Copper loss
Eddy-current
Hysteresis loss
Leakage loss
The illustrated transformer is (a) what type, and (b) in what direction is the current flowing in the secondary?
(a) Like-wound (b) ↑
(a) Unlike-wound (b) ↑
(a) Like-wound (b) ↓
(a) Unlike-wound (b) ↓
Identify this schematic symbol:
Air core transformer
Iron core transformer
Center tap transformer
Iron core, center tap transformer
Identify this schematic symbol:
Air core transformer
Iron core transformer
Center tap transformer
Iron core, center tap transformer
