Electrical Level 3 Transformers Quiz
What type of circuit uses the alternating magnetic field of one coil to generate voltage in a second coil?
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What type of transformer has primary circuits that have part of a winding in common?
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Which of the following best describes a transformer that increases the voltage on the primary from 120v to 1200v on the secondary?
A step up transformer
What type of transformer is shown in the given wiring diagram?
Control transformer
A three phase four wire system that has the advantage of providing three phase power and allowing lighting to be connected between any of the secondary phases and the neutral would have a __________?
D.Wye secondary
What type of transformer provides 120v between the center tapped terminal and each ungrounded terminal on either side and 240v across the full winding of each phase?
Delta-Delta
Which winding of a transformer is connected to the load?
Secondary
The image shows the basic components of a
Transformer
What is the Kva of the pictured transformer if the VA required is 33,000?
33 KVa
Which of the following types of transformers must be installed in a vault?
35Kv oil insulated transformer
(image may vary) What set of tap connections would yield the highest secondary voltage if secondary leads are attached to the x points and numbers 2 through 7 represent taps?
7-2(?)
What components are installed to increase the power factor and decrease the cost of electricity caused by large inductive loads?
Capacitors
A lagging current for a motor or inductive device is represented by a power factor of _________?
Less than one
What forces are always present in an AC circuit?
Inductance and true power
How can the need for additional KVAR's be reduced in large inductive loads with low power factors?
Installing capacitors
To ensure maximum safety in a control transformer the secondary control circuit is _____?
Isolated from the primary circuit
When voltage is stepped down in a transformer what happens to the current in the same current?
It is stepped up
Which section of the NEC contains transformer nameplate requirements?
NEC Article 450.11
Capacitors are covered in _______
NEC Article 460
The installation of resistors and reactors is covered in______?
NEC article 470
Which transformer is almost always required to be installed in a vault?
Oil-insulated
What type of transformers has more turns in the primary than the secondary?
Step down
Secondary voltage in a transformer can be increased or decreased by connecting various _____
Taps
Transformer cores support ______
Two windings