Question 1

The isolation transformer ____.

Accepted Answer

A)   cannot have a turns ratio of 1:1
B)   does not actually electrically isolate the primary and secondary windings
C)   greatly reduces the voltage spike
D)   greatly prolongs the voltage spikeE) A) and D)
F) A) and B)

Question 2

A basic law concerning transformers is that all values of a transformer are proportional to its ____ ratio.

Accepted Answer

A)   turns
B)   induction
C)   current
D)   primaryE) B) and D)
F) All of the above

Question 3

Figure 13-17  Find the values specified in the following questions:
-The amount of primary current needed to supply the first secondary winding is ____ A.

Accepted Answer

A)   1.51
B)   2.11
C)   2.61
D)   3.01E) A) and B)
F) A) and C)

Question 4

Assume an isolation transformer has a primary voltage of 120 V and a secondary voltage of 500 V. The turns ratio is 1:____.

Accepted Answer

A)   0.231
B)   1
C)   2.36
D)   4.17E) B) and C)
F) None of the above

Question 5

Loads that are intended to operate on 120 V connect from the center tap or ____ to one of the secondary lines.

Accepted Answer

A)   positive
B)   neutral
C)   negative
D)   primaryE) C) and D)
F) None of the above

Question 6

The ____ transformer changes the high voltage of power company distribution lines to the common 240/120-V used to supply power to most homes and many businesses.

Accepted Answer

A)   distribution
B)   HIVOLT
C)   residential
D)   commonE) B) and C)
F) None of the above A

Question 7

A good rule for any type of transformer is that power in ____.

Accepted Answer

A)   is slightly greater than power out
B)   is exponentially greater than power out
C)   is less than power out
D)   must equal power outE) None of the above
F) B) and C)

Question 8

Almost all nameplates will list the primary voltage, secondary voltage, and ____.

Accepted Answer

A)   serial number
B)   impedance
C)   KVA (kilo-volt-amps)  rating
D)   temperature riseE) B) and C)
F) C) and D) C

Question 9

The nameplate lists the current rating of the windings.

Accepted Answer

A) True 
 B)False

Question 10

The ability of one coil to induce a voltage into another coil is called ____ induction.

Accepted Answer

A)   secondary
B)   core
C)   primary
D)   mutualE) C) and D)
F) A) and D)

Question 11

Loads that are intended to operate on 120 V, such as water heaters, electric resistance heating units, and central air conditioners, are connected directly across the lines of the secondary.

Accepted Answer

A) True 
 B)False

Question 12

Transformer values of voltage, current, and turns can be computed using formulas.

Accepted Answer

A) True 
 B)False

Question 13

Figure 13-17  Find the values specified in the following questions:
-The turns ratio of the first secondary is 1:____.

Accepted Answer

A)   2.14
B)   3.55
C)   4.67
D)   5.77E) A) and C)
F) A) and D)

Question 14

Figure 13-17  Find the values specified in the following questions:
-The number of turns of wire in the first secondary winding is ____.

Accepted Answer

A)   854
B)   1005
C)   1277
D)   1401E) All of the above
F) A) and B)

Question 15

Transformers are among the least efficient machines known.

Accepted Answer

A) True 
 B)False

Question 16

When computing the values of a transformer with multiple secondary windings, treat each secondary as part of the transformer group as a whole.

Accepted Answer

A) True 
 B)False

Question 17

The ____ winding of a transformer is the power input winding.

Accepted Answer

A)   secondary
B)   primary
C)   tertiary
D)   coreE) A) and B)
F) None of the above

Question 18

The ____ current is the amount of current required to magnetize the core of the transformer.

Accepted Answer

A)   primary
B)   spike
C)   core
D)   excitationE) All of the above
F) B) and D)

Question 19

Figure 13-17  Find the values specified in the following questions:
-The current flow in the first secondary is ____ A.

Accepted Answer

A)   0.49
B)   0.56
C)   0.63
D)   0.70E) A) and C)
F) All of the above

Question 20

____ are one-winding transformers.

Accepted Answer

A)   Megatransformers
B)   Isolation transformers
C)   Distribution transformers
D)   AutotransformersE) A) and B)
F) B) and C) D

Exam 13: Transformers

The isolation transformer ____.

Correct AnswerverifiedShow Answer

A basic law concerning transformers is that all values of a transformer are proportional to its ____ ratio.

Correct AnswerverifiedShow Answer

Figure 13-17 Find the values specified in the following questions: -The amount of primary current needed to supply the first secondary winding is ____ A.

Correct AnswerverifiedShow Answer

Assume an isolation transformer has a primary voltage of 120 V and a secondary voltage of 500 V. The turns ratio is 1:____.

Correct AnswerverifiedShow Answer

Loads that are intended to operate on 120 V connect from the center tap or ____ to one of the secondary lines.

Correct AnswerverifiedShow Answer

The ____ transformer changes the high voltage of power company distribution lines to the common 240/120-V used to supply power to most homes and many businesses.

Correct AnswerverifiedA

A good rule for any type of transformer is that power in ____.

Correct AnswerverifiedShow Answer

Almost all nameplates will list the primary voltage, secondary voltage, and ____.

Correct AnswerverifiedC

The nameplate lists the current rating of the windings.

Correct AnswerverifiedShow Answer

The ability of one coil to induce a voltage into another coil is called ____ induction.

Correct AnswerverifiedShow Answer

Loads that are intended to operate on 120 V, such as water heaters, electric resistance heating units, and central air conditioners, are connected directly across the lines of the secondary.

Correct AnswerverifiedShow Answer

Transformer values of voltage, current, and turns can be computed using formulas.

Correct AnswerverifiedShow Answer

Figure 13-17 Find the values specified in the following questions: -The turns ratio of the first secondary is 1:____.

Correct AnswerverifiedShow Answer

Figure 13-17 Find the values specified in the following questions: -The number of turns of wire in the first secondary winding is ____.

Correct AnswerverifiedShow Answer

Transformers are among the least efficient machines known.

Correct AnswerverifiedShow Answer

When computing the values of a transformer with multiple secondary windings, treat each secondary as part of the transformer group as a whole.

Correct AnswerverifiedShow Answer

The ____ winding of a transformer is the power input winding.

Correct AnswerverifiedShow Answer

The ____ current is the amount of current required to magnetize the core of the transformer.

Correct AnswerverifiedShow Answer

Figure 13-17 Find the values specified in the following questions: -The current flow in the first secondary is ____ A.

Correct AnswerverifiedShow Answer

____ are one-winding transformers.

Correct AnswerverifiedD

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A

Correct Answer
verified

Correct Answer
verified
C

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
D