Principles of Electricity

Question 1

In a _____, the voltage is stepped up on the secondary side which causes the current to drop.

Answer 1

Step Up Transformer

Question 2

What is the benefit of higher power factor?

Answer 2

Lower operating cost

Question 3

How are the leads arranged in a wye or star connection?

Answer 3

Three are connected together, and three are brought out to connect to the load

Question 4

The line currents of a delta-connected generator are _____

Answer 4

Equal in value and 120 degrees apart

Question 5

Clamp on ammeters measure current by measuring what?

Answer 5

The strength of the flux field around a conductor

Question 6

What needs to happen in an AC generator before it can produce voltage?

Answer 6

The rotor must be excited

Question 7

What is a rotor?

Answer 7

The rotating part of an AC generator

Question 8

Why is three phase power preferred to single phase?

Answer 8

Less copper is required to deliver the same amount of power

Question 9

When analyzing a parallel inductive-resistive-capacitive circuit, what is assumed?

Answer 9

Each branch is purely inductive, capacitive, or resistive

Question 10

_____ must be known in order to calculate inductive resistance

Answer 10

Frequency

Question 11

In a parallel-Inductive-capacitive circuit, the power factor is equal to _____

Answer 11

The true power divided by the apparent power

Question 12

In a series-inductive-capacitive circuit, inductive and capacitive voltages are not _____

Answer 12

In phase with each other

Question 13

In a series AC circuit, _____ and _____ are in phase with each other

Answer 13

Source voltage and line current

Question 14

What is the standard power source line frequency in the United States?

Answer 14

60Hz

Question 15

What must be known in an inductive AC circuit to find current?

Answer 15

The source voltage

Question 16

What is CEMF and how is it created?

Answer 16

Counter electomotive force, created by a change in current caused by a constantly changing magnetic field

Question 17

What is a pure inductive circuit?

Answer 17

An AC circuit with no resistance

Question 18

What is considered low power factor?

Answer 18

Any power factor less than 90%

Question 19

What is the difference between true power and reactive power?

Answer 19

True power is supplied to a resistive load to do work

Question 20

_____ circuits are frequently used in electronics applications

Answer 20

Series/Parallel Resistive-Capacitive circuits

Question 21

When a circuit is _____, the current lags the source voltage.

Answer 21

Inductive

Question 22

Increasing the frequency in a parralel inductive-resistive-capacitive circuit causes current flow to decrease in the _____ branch

Answer 22

Inductive

Question 23

Inductive capacitive branches of a circuit _____ have resistance

Answer 23

Do

Question 24

Using Ohm’s Law, current is often reduce to _____ in order to calculate total line current.

Answer 24

its vertical and horizontal components

Question 25

_____ is the opposition to current flow by a capacitor

Answer 25

Capacitive Resistance

Question 26

When analyzing a series circuit, _____ is used as a reference for all other circuit parameters

Answer 26

Current

Question 27

_____ is the same across all branch circuits of a parallel inductive-resistive-capacitive circuit

Answer 27

Voltage

Question 28

Series/parallel inductive-resistive-capacitive circuitsare usually analyzed to calculate _____, _____, _____, but not _____

Answer 28

Power Factor, Circuit Power, Total Circuit Current, Frequency

Question 29

What is Eddy Current Loss?

Answer 29

Power loss in a transformer or motor due to induced current in surrounding metal structures

Question 30

What is an Isolation Transformer?

Answer 30

A transformer with equal primary and secondary winding used to separate the source from the load

Question 31

What is a swamping resistor?

Answer 31

A resistor used to suppress the high inductive kick of an exciter current

Question 32

Three-phase power system use three individual _____ to transmit power

Answer 32

Conductors

Question 33

_____ measure current by measuring the strength of the current around a single conductor

Answer 33

Clamp-On Ammeters

Question 34

A _____ is a test instrument used to measure true power in a circuit

Answer 34

Wattmeter

Question 35

A _____ is not an example of an inductive load

Answer 35

Motor Under Full Load

Question 36

What is plugging?

Answer 36

Switching polarities in a motor to brake

Question 37

Frequency changes only directly effect _____, the rest of the parameters are indirectly affected.

Answer 37

Capacitive Reactance

Question 38

In a pure capacitive circuit, the current _____ the source voltage by 90 degrees

Answer 38

Leads

Question 39

In a series-capacitive circuit _____ is the same at all points for all components

Answer 39

Current

Question 40

What is the common method for correcting power factor?

Answer 40

Connecting capacitors across the load

Question 41

What is Power Factor?

Answer 41

The ratio of true power to apparent power

Question 42

True power is measured in _____

Answer 42

Watts