Question 1

To test for harmonic distortion in a three-phase four-wire system, measure all phase currents and the
current with both a true­RMS indicating ammeter and an average­indicating ammeter.

Accepted Answer

neutral

Question 2

Harmonics on single-phase powerlines are generally caused by a device such as a .

Accepted Answer

A)   triac light dimmer
B)   lamp with an incandescent bulb
C)   single-speed motor
D)   heater A

Question 3

To calculate the maximum load that should be placed on a transformer, the derating factor by the kilovolt-ampere capacity of the transformer.

Accepted Answer

multiply

Question 4

Harmonic problems generally involve of the transformer.

Accepted Answer

The answer of Harmonic problems generally involve of the transformer....

Question 5

The formula for determining the transformer harmonic derating factor produces a value somewhere between _____.

Accepted Answer

A)   zero and one
B)   zero and ten
C)   zero and the RMS phase current
D)   zero and the instantaneous peak value

Question 6

What are voltages or currents that operate at a frequency that is a multiple of the fundamental power frequency?

Accepted Answer

A)   pulsations
B)   loads
C)   phases
D)   harmonics

Question 7

Harmonics are produced by linear loads that draw current in a continuous manner.

Accepted Answer

A) True 
 B)False

Question 8

What device should be used to determine the name, sequence, and amount of harmonic distortion?

Accepted Answer

A)   true­RMS ammeter
B)   harmonic analyzer
C)   average ammeter
D)   harmonic meter

Question 9

The of a harmonic refers to whether the harmonic is the second, third, fourth, or so on of the fundamental frequency.

Accepted Answer

A)   name
B)   frequency
C)   sequence
D)   magnitude

Question 10

Because the phasor rotation of a negative harmonic is the same as that of the fundamental frequency, it will tend to
weaken the rotating magnetic field of an induction motor causing it to produce much greater torque.

Accepted Answer

A) True 
 B)False

Question 11

The of a harmonic refers to the phasor rotation with respect to the fundamental waveform.

Accepted Answer

A)   name
B)   frequency
C)   sequence
D)   magnitude

Question 12

One method of determining harmonic problems on single-phase systems is to make two separate current checks. When this is performed, a ratio of average to true-RMS equal to 0.5 indicates harmonic distortion.

Accepted Answer

A)   no
B)   moderate
C)   extreme

Question 13

A particular set of harmonics called "triplens" has a sequence.

Accepted Answer

A)   negative
B)   positive
C)   zero

Question 14

The odd multiples of the third harmonic (third, ninth, fifteenth, twenty­first, etc.) are called .

Accepted Answer

The answer of The odd multiples of the third harmonic...

Question 15

Harmonics are classified by name, frequency, and sequence.

Accepted Answer

A) True 
 B)False

Question 16

When pulsating currents are connected to a three-phase four-wire system, triplen harmonic frequencies disrupt the normal phasor relationship of the phase currents and can cause the phase currents to add in the neutral conductor.

Accepted Answer

A) True 
 B)False

Question 17

A negative­sequence harmonic would rotate in the direction of the fundamental frequency.

Accepted Answer

The answer of A negative­sequence harmonic would rotate in the...

Question 18

One method of determining harmonic problems on single-phase systems is to make two separate current checks. When this is performed, a ratio of average to true-RMS equal to one indicates harmonic distortion.

Accepted Answer

A)   no
B)   moderate
C)   extreme

Question 19

To minimize interference, telecommunication cables are run as close to phase conductors as possible and as far
away from the neutral conductor as possible.

Accepted Answer

A) True 
 B)False

Question 20

Given a harmonic with a fundamental power frequency of 60 hertz, what would be the frequency of the fourth harmonic?

Accepted Answer

A)   120 hertz
B)   180 hertz
C)   240 hertz
D)   300 hertz

Exam 35: Harmonics and their Effects on Electrical Systems

To test for harmonic distortion in a three-phase four-wire system, measure all phase currents and the current with both a trueRMS indicating ammeter and an averageindicating ammeter.

Harmonics on single-phase powerlines are generally caused by a device such as a .

To calculate the maximum load that should be placed on a transformer, the derating factor by the kilovolt-ampere capacity of the transformer.

Harmonic problems generally involve of the transformer.

The formula for determining the transformer harmonic derating factor produces a value somewhere between _____.

What are voltages or currents that operate at a frequency that is a multiple of the fundamental power frequency?

Harmonics are produced by linear loads that draw current in a continuous manner.

What device should be used to determine the name, sequence, and amount of harmonic distortion?

The of a harmonic refers to whether the harmonic is the second, third, fourth, or so on of the fundamental frequency.

Because the phasor rotation of a negative harmonic is the same as that of the fundamental frequency, it will tend to weaken the rotating magnetic field of an induction motor causing it to produce much greater torque.

The of a harmonic refers to the phasor rotation with respect to the fundamental waveform.

One method of determining harmonic problems on single-phase systems is to make two separate current checks. When this is performed, a ratio of average to true-RMS equal to 0.5 indicates harmonic distortion.

A particular set of harmonics called "triplens" has a sequence.

The odd multiples of the third harmonic (third, ninth, fifteenth, twentyfirst, etc.) are called .

Harmonics are classified by name, frequency, and sequence.

When pulsating currents are connected to a three-phase four-wire system, triplen harmonic frequencies disrupt the normal phasor relationship of the phase currents and can cause the phase currents to add in the neutral conductor.

A negativesequence harmonic would rotate in the direction of the fundamental frequency.

One method of determining harmonic problems on single-phase systems is to make two separate current checks. When this is performed, a ratio of average to true-RMS equal to one indicates harmonic distortion.

To minimize interference, telecommunication cables are run as close to phase conductors as possible and as far away from the neutral conductor as possible.

Given a harmonic with a fundamental power frequency of 60 hertz, what would be the frequency of the fourth harmonic?

Exam 35: Harmonics and their Effects on Electrical Systems

To test for harmonic distortion in a three-phase four-wire system, measure all phase currents and the current with both a true­RMS indicating ammeter and an average­indicating ammeter.

Harmonics on single-phase powerlines are generally caused by a device such as a .

To calculate the maximum load that should be placed on a transformer, the derating factor by the kilovolt-ampere capacity of the transformer.

Harmonic problems generally involve of the transformer.

The formula for determining the transformer harmonic derating factor produces a value somewhere between _____.

What are voltages or currents that operate at a frequency that is a multiple of the fundamental power frequency?

Harmonics are produced by linear loads that draw current in a continuous manner.

What device should be used to determine the name, sequence, and amount of harmonic distortion?

The of a harmonic refers to whether the harmonic is the second, third, fourth, or so on of the fundamental frequency.

Because the phasor rotation of a negative harmonic is the same as that of the fundamental frequency, it will tend to weaken the rotating magnetic field of an induction motor causing it to produce much greater torque.

The of a harmonic refers to the phasor rotation with respect to the fundamental waveform.

One method of determining harmonic problems on single-phase systems is to make two separate current checks. When this is performed, a ratio of average to true-RMS equal to 0.5 indicates harmonic distortion.

A particular set of harmonics called "triplens" has a sequence.

The odd multiples of the third harmonic (third, ninth, fifteenth, twenty­first, etc.) are called .

Harmonics are classified by name, frequency, and sequence.

When pulsating currents are connected to a three-phase four-wire system, triplen harmonic frequencies disrupt the normal phasor relationship of the phase currents and can cause the phase currents to add in the neutral conductor.

A negative­sequence harmonic would rotate in the direction of the fundamental frequency.

One method of determining harmonic problems on single-phase systems is to make two separate current checks. When this is performed, a ratio of average to true-RMS equal to one indicates harmonic distortion.

To minimize interference, telecommunication cables are run as close to phase conductors as possible and as far away from the neutral conductor as possible.

Given a harmonic with a fundamental power frequency of 60 hertz, what would be the frequency of the fourth harmonic?

To test for harmonic distortion in a three-phase four-wire system, measure all phase currents and the current with both a trueRMS indicating ammeter and an averageindicating ammeter.

The odd multiples of the third harmonic (third, ninth, fifteenth, twentyfirst, etc.) are called .

A negativesequence harmonic would rotate in the direction of the fundamental frequency.