Class

Question 1

The simplest circuit breaker is

Answer 1

The ordinary knife switch

Question 2

This type of circuit breaker the arc is extinguished by a blast of air

Answer 2

Air blast breakers

Question 3

In oil circuit breakers, the arch originates in oil, but the heat of the ark immediately evaporates the surrounding oil this causes

Answer 3

The oil to disassociate into carbon and a substantial volume of gas is hydrogen, high-pressure the hydrogen, then suffocates the ark

Question 4

With the nerve gas breakers, the gas will liquefy so right away that it must be kept heated if

Answer 4

It must be kept heated, so it doesn’t liquefy if it is to be used outdoors

Question 5

Why is the speed of a circuit breaker desirable?

Answer 5

So that it can minimize the arc , protect itself and protect everything around it

Question 6

List the three main circuit breaker ratings

Answer 6

Breaker voltage, continuous current, interrupting current

Question 7

A circuits interrupting time is

Answer 7

The rating that gives you the amount of time it takes to open

Question 8

Three trip free power circuit breakers are

Answer 8

Electrical, mechanical pneumatic

Question 9

The four types of insulating media in circuit breakers are

Answer 9

Air type, oil type, gas type, and vacuum type

Question 10

In a wye connected system, the line voltage is higher than the phase voltage by

Answer 10

A factor of the square root of three or 1.732

Question 11

Three phase voltages are 120° out of

Answer 11

Out of phase with each other, not in phase with each other

Question 12

The line current of a delta connection is higher than the phase current by

Answer 12

A factor of the square root of three or 1.732

Question 13

A magnetically operated machine that can change values of voltage current and impedance without a change of frequency is

Answer 13

A transformer

Question 14

The efficiency among transformers commonly range from

Answer 14

90 to 99%

Question 15

All values of a transformer are

Answer 15

Proportional to its turn ratio

Question 16

The ratio of the amount of turns in the primary winding compared to the amount of turns in the secondary whining is

Answer 16

The turns ratio

Question 17

The transformer with the secondary winding is physically an electrically isolated from the primary whining is

Answer 17

An isolation transformer

Question 18

When a coil induces a voltage into itself, it is known as

Answer 18

Self induction

Question 19

The ability of one coil to induce voltage into another coil is

Answer 19

Called mutual induction

Question 20

A transformer with one winding that is used for both primary and secondary is

Answer 20

An auto transformer

Question 21

What are the three functions of transformer oil

Answer 21

The oil provides electric insulation between the windings and the case it is also used to help provide cooling and to prevent the formation of moisture

Question 22

Name the phenomenon detrimental to the success of the power circuit breaker

Answer 22

The plasma arc

Question 23

What is the primary function of the power circuit breaker?

Answer 23

Protection

Question 24

What are harmonics and when do they occur?

Answer 24

Harmonics are voltages or currents that operate at a frequency that is a multiple of the fundamental power frequency. They occur at the second harmonic that would be 120 Hz or further multiples.

Question 25

Which connection has equal line and phase current

Answer 25

A wye connection

Question 26

The biggest disadvantage of using a sulfur hexa fluoride breaker is

Answer 26

The byproducts of the gas in the ark are corrosive

Question 27

True or false a transformer can change frequency

Answer 27

False

Question 28

The current that the breaker will carry indefinitely without exceeding a specific temperature rise is

Answer 28

The continuous current rating

Question 29

The most common gas used in a power circuit breaker is

Answer 29

Sulfur hexa, fluoride or SF six

Question 30

The major disadvantage of oil circuit breakers is

Answer 30

Fires or explosion

Question 31

Which winding has the power and which winding has the load?

Answer 31

The winding that has the powers is the primary and the winding that has the low is the secondary

Question 32

Which connection has equal line and phase voltage

Answer 32

Delta connection