Question 1

What procedure should be used to make the low-voltage connections?

Accepted Answer

1. Energize the three-phase, wye-connected, high-voltage side of the transformer bank. The voltage output of each of the three transformers must be the same as the nameplate rating.
2. Deenergize the primary. Connect the X₂ ends of two low-voltage secondary windings. With all three X₁s open and clear, energize the primary. If the connections are made correctly, the voltage across the open ends is square roof of 3 times the secondary winding voltage. In this case, the voltage across the open ends is 208 V, as indicated in the vector diagram.

Question 2

When two or three single-phase transformers are used to transform voltages on a three-phase system, they are known as a transformer connection.

Accepted Answer

A) True 
 B)False  False

Question 3

A(n) ____________________ connection is used when three single-phase transformers are used to step down as three-phase voltage of 2400 V to 240 V, three phase.

Accepted Answer

delta-delta

Question 4

What is the purpose of a harmonic analyzer?

Accepted Answer

The harmonic analyzer will det

Question 5

In general, the low-voltage winding leads are not marked.

Accepted Answer

A) True 
 B)False

Question 6

It is generally not practical to remove the equipment causing the harmonic distortion, so other methods must be employed.

Accepted Answer

A) True 
 B)False

Question 7

The primary side of the delta-connected transformer may be connected so as to reverse the ____________________ of one of its legs.

Accepted Answer

The answer of The primary side of the delta-connected transformer...

Question 8

In a T connection, one transformer is generally referred to as the main transformer and the other is called the ____________________ transformer.

Accepted Answer

The answer of In a T connection, one transformer is...

Question 9

The wye-wye connection cannot be used in those applications where the load on the secondary side is balanced.

Accepted Answer

A) True 
 B)False

Question 10

List three general procedures for dealing with harmonics.

Accepted Answer

1. In a three-phase, four-wire system, t

Question 11

Determining whether a problem with harmonics exists in a three-phase system is similar to determining the problem in a single-phase system.

Accepted Answer

A) True 
 B)False

Question 12

List two advantages of a 277/480-V, three-phase, four-wire system.

Accepted Answer

The voltage drop is reduced in feeders a

Question 13

The most accurate method for determining whether there is a harmonics problem is to use a(n) ____________________.

Accepted Answer

The answer of The most accurate method for determining whether...

Question 14

How are primary windings connected?

Accepted Answer

The high-voltage primary windings are co

Question 15

A(n) ____________________ wire is added to eliminate unbalanced voltages.

Accepted Answer

The answer of A(n) ____________________ wire is added to eliminate...

What procedure should be used to make the low-voltage connections?

When two or three single-phase transformers are used to transform voltages on a three-phase system, they are known as a transformer connection.

A(n) ____________________ connection is used when three single-phase transformers are used to step down as three-phase voltage of 2400 V to 240 V, three phase.

What is the purpose of a harmonic analyzer?

In general, the low-voltage winding leads are not marked.

It is generally not practical to remove the equipment causing the harmonic distortion, so other methods must be employed.

The primary side of the delta-connected transformer may be connected so as to reverse the ____________________ of one of its legs.

In a T connection, one transformer is generally referred to as the main transformer and the other is called the ____________________ transformer.

The wye-wye connection cannot be used in those applications where the load on the secondary side is balanced.

List three general procedures for dealing with harmonics.

Determining whether a problem with harmonics exists in a three-phase system is similar to determining the problem in a single-phase system.

List two advantages of a 277/480-V, three-phase, four-wire system.

The most accurate method for determining whether there is a harmonics problem is to use a(n) ____________________.

How are primary windings connected?

A(n) ____________________ wire is added to eliminate unbalanced voltages.

Introduction to Alternating Current

Alternating-Current Circuits Containing Resistance

Inductance in Alternating-Current Circuits

Series Circuitsresistance and Impedance

Capacitors and Rc Time Constants

Capacitors in Alternating-Current Circuits

Series Circuits: Resistance, Inductive Reactance, and Capacitive Reactance

Ac Parallel Circuits

Seriesparallel Circuits

Three-Phase Systems

Ac Instruments and Meters

Alternating-Current Generators

Transformers

Special Transformer Applications

Three-Phase Induction Motors

The Synchronous Motor

Single-Phase Motors

Control Circuits

Filters

Exam 14: Transformer Connections for Three-Phase Circuits

What procedure should be used to make the low-voltage connections?

When two or three single-phase transformers are used to transform voltages on a three-phase system, they are known as a transformer connection.

A(n) ____________________ connection is used when three single-phase transformers are used to step down as three-phase voltage of 2400 V to 240 V, three phase.

What is the purpose of a harmonic analyzer?

In general, the low-voltage winding leads are not marked.

It is generally not practical to remove the equipment causing the harmonic distortion, so other methods must be employed.

The primary side of the delta-connected transformer may be connected so as to reverse the ____________________ of one of its legs.

In a T connection, one transformer is generally referred to as the main transformer and the other is called the ____________________ transformer.

The wye-wye connection cannot be used in those applications where the load on the secondary side is balanced.

List three general procedures for dealing with harmonics.

Determining whether a problem with harmonics exists in a three-phase system is similar to determining the problem in a single-phase system.

List two advantages of a 277/480-V, three-phase, four-wire system.

The most accurate method for determining whether there is a harmonics problem is to use a(n) ____________________.

How are primary windings connected?

A(n) ____________________ wire is added to eliminate unbalanced voltages.

Introduction to Alternating Current

Alternating-Current Circuits Containing Resistance

Inductance in Alternating-Current Circuits

Series Circuitsresistance and Impedance

Capacitors and Rc Time Constants

Capacitors in Alternating-Current Circuits

Series Circuits: Resistance, Inductive Reactance, and Capacitive Reactance

Ac Parallel Circuits

Seriesparallel Circuits

Three-Phase Systems

Ac Instruments and Meters

Alternating-Current Generators

Transformers

Special Transformer Applications

Three-Phase Induction Motors

The Synchronous Motor

Single-Phase Motors

Control Circuits

Filters