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Third Year Millwright > Electrical > Flashcards

Electrical Flashcards

1
Q

What is the force exerted by protons and electrons?

A

Electric charge

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2
Q

What is the charge for
Protons
Electrons
Neutrons

A

Positive
Negative
No charge

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3
Q

What are the four distinct states of matter?

A

Solid, liquid, gas, plasma

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4
Q

If an object has more protons than electrons, what is its electrical charge?

A

It is positively charged.

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5
Q

What are free electrons?

A

They are electrons that loosely bonded around the nucleus, and can be easily knocked loose.

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6
Q

What is a molecule?

A

The smallest part that matter can be divided into, without changing its makeup.

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7
Q

Describe static electricity

A

When the positive and negative charges are balanced and the charge does not move

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8
Q

Describe unbalanced electrical charges

A

Unbalanced electrical charges is also known as electrical flow, or current flow. The greater the unbalance, the greater the voltage

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9
Q

What is magnetism?

A

It is the physical phenomenon caused by electron movement.

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10
Q

Describe a permanent magnet

A

The magnetic property is caused by the spinning of electrons in the atoms that make up the material the magnet is formed out of.

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11
Q

Describe an electromagnet

A

Caused by electrons moving through a coil of wire wound around a core material

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12
Q

How are magnetic fields pictured?

A

They are pictured as magnetic flux lines.

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13
Q

What are some common materials for permanent magnets?

A

Steel alloys, cobalt, nickel, alnico, platinum and cobalt alloys, samarium and cobalt alloys

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14
Q

What does a compass do near a wire carrying an electric charge?

A

It causes the needle to deflect at a right angle to the wire.

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15
Q

What are the basic principles of electromagnetism?

A
  • moving electrically charged particles creates magnetic fields
  • magnetic fields attract or repel moving charged particles
  • moving magnetic fields near charged particles causes current flow
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16
Q

What does passing a magnetic field through a conductor generate?

A

Induced electromotive force(voltage). The current that is caused to flow is called induced current.

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17
Q

What is permeability in regards to electromagnets?

A

The ease in which a material can be magnetized by a solenoid.

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18
Q

What is a good conductor?

A

A material that exhibits low resistance to current flow

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19
Q

Give some examples of good conductors

A

Silver-best
Copper-second
Gold-third, but only one that resists oxidation

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20
Q

What makes a good insulator?

A

A material that is a poor conductor of electricity. Some examples are glass, mica, dry wood, plastics

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21
Q

What is a semiconductor?

A

A material that is neither a good conductor nor a good insulator.

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22
Q

Describe direct current (DC)

A

The flow of free electrons in the conductors is always in the same direction, and has fixed polarity.

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23
Q

What is ohms law formula?

A

E=IxR

24
Q

What is E in formula?

A

E=power=volts=potential difference

25
Q

What is I in formula?

A

I=current flow=amps

26
Q

What is R in formula?

A

R=resistance=ohms

27
Q

Changing AC to DC voltage is done with what?

A

Rectifier

28
Q

What is our RMS, and what is the value of it?

A

Root mean square, and its value is .707

29
Q

What is the pattern of a single phase in one cycle?

A

Sine wave

30
Q

How is voltage induced?

A

It is done when a conductor cuts magnetic lines of flux. The maximum induced voltage occurs when the conductor is traveling at right angles through the lines of flux

31
Q

What is frequency?

A

Frequency is the number of cycles and alternating current generates for second also known as hertz

32
Q

What is the sine wave form for a three-phase motors?

A

The phases are out of phase by 120°

33
Q

How was DC voltage changed to AC?

A

Through an inverter

34
Q

How does an electric current flow?

A

There must be a potential difference between two points of the supplying device the potential difference is called voltage measured in volts

35
Q

What are amps?

A

Amps are the rate of flow of electrons in an electrical circuit

36
Q

How many watts in 1 hp?

A

746 Watts

37
Q

Describe an open circuit

A

It is a circuit that has an incomplete pass for current flow because a switch is open

38
Q

Materials fall into one of three categories based on the resistance to current flow of that material. What are the three categories

A

Conductors, insulators, semi conductors

39
Q

Describe electromotive force

A

The voltage generated by moving a conductor through a magnetic field

40
Q

Describe resistance

A

The property of the materials that opposes the flow of an electric current

41
Q

List three factors that determine the amount of voltage induced in a coil

A

Material of the coils core, frequency, amp turns

42
Q

List four factors that affect the resistance of a conductor

A
  • material
  • cross-sectional area
  • length of conductor
  • temperature
43
Q

What does alternating current mean?

A

When the current changes polarity continuously and regularly

44
Q

If an atom has more protons and electrons it is said to have what kind of a charge?

A

A positive charge

45
Q

A metal that can be easily magnetized by solenoid is said to have what?

A

High permeability

46
Q

When a conductor is passed through a magnetic field what is created?

A

Induced current

47
Q

A material whose Atoms have free electrons in its outer valence is said to be what?

A

A good conductor

48
Q

Current that flows from a positive to negative is called what

A

Conventional flow

49
Q

In the series circuit what stays constant throughout?

A

The current or amps

50
Q

What color is the grounded circuit conductor, or neutral wire in residential wiring

A

White

51
Q

What is the wiring color combination for industrial three phase?

A

Black, red, blue

52
Q

What is the amp a measure of?

A

Electron flow

53
Q

What does a fuse protect the circuit from?

A

Over current

54
Q

Voltage in a parallel circuit is?

A

Equal through each branch of the circuit

55
Q

Is voltage measured in series or parallel with the load?

A

In parallel with the load

56
Q

Time delay fuses have what?

A

Dual elements

Third Year Millwright (12 decks)

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