Electrical

Question 1

What are the four distinct states of matter?

Answer 1

solid
liquid
gas
plasma

Question 2

Matter consists of?

Answer 2

tiny particles called molecules

Question 3

If protons repel protons and electrons repel electrons what does a proton and a electrons do?

Answer 3

Attract to each other

Question 3

Molecules are made up of?

Answer 3

combinations of atoms

Question 3

Protons and electrons exert a force known as?

Answer 3

electric charge

Question 3

If an object has more protons than electrons it is_______?

Answer 3

positively charged

Question 4

If there is more electrons than neutrons it is _______?

Answer 4

negatively charged

Question 5

Electricity is a useful form of energy derived from unbalanced electrical charges in materials. when these charges do not move, they are called _________and they cause attraction or repulsion objects in their close proximity.

Answer 5

static electricity

Question 6

When the electric charges move in a conductor, the current flow causes magnetic fields around that conductor. all electrical equipment is designed around the interaction of electric and _________ fields?

Answer 6

magnetic

Question 7

The Law of electric charges states?

Answer 7

• like charges Repel one another
• unlike charges attract one another

Question 8

what are some common materials for common magnets?

Answer 8

• Steel alloys
• Cobalt
• nickel
• alnico (iron, aluminum, nickel, and cobalt
• platinum and cobalt alloys
• samarium and cobalt alloys

Question 9

Electromagnetism is?

Answer 9

the interactive relationship between electric charge and magnetic flux

Question 10

what is a conductor?

Answer 10

a material that exhibits low resistance to current flow, such as copper, silver, gold, aluminum.

Question 11

what is a insulator?

Answer 11

a material that is a poor conductor of electrical current. Insulators offer a very high resistance to current flow.
glass, mica, dry wood and plastics are all good examples

Question 12

What is direct current?

Answer 12

If the current flow is always in the same direction. (Dc) fixed polarity.

Question 13

What are some DC currents?

Answer 13

Portable welder
Car battery
Solar energy cell

Question 14

Uses of DC power?

Answer 14

-Charging batteries
- operating electrical equipment
- operating dc motors
- welding
- industrial electromagnets

Question 15

If the current flowing in a circuit from a source of voltage changes polarity (direction of current flow) continuously and regularly it is called?

Answer 15

Alternating current (AC)

Question 16

What is the standard power line frequency in North America?

Answer 16

60 cycles per second or 60 hertz

Question 17

_______ refers to single voltage that creates a potential difference between only two conductors.

Answer 17

Single phase

Question 18

________ refers to three different voltages that interact to produce potential differences between the three conductors that supply the three phase loads. These phases are out of phase with each other by 120 degrees.

Answer 18

Three-phase

Question 19

The potential differences are between phases:

Answer 19

Question 20

What are some sources of ac power?

Answer 20

Gas powered alternator
- automobile alternator
- electronic inverter

Question 21

Voltage can be thought of as?

Answer 21

Electrical pressure

One volt potential difference causes one ampere of current to flow through a resistance of one ohm.

Question 22

If there is an incomplete path for current to flow it is a ______ circuit?

Answer 22

Open

Question 23

Current is flowing through a _______ (complete path)

Answer 23

Closed circuit

Question 24

Series connection

Answer 24

Question 25

Parallel connection

Answer 25

Question 26

Series-parallel connection

Answer 26

Question 27

________ is the property of a material that opposes the flow of an electric current. It is measured in ohms.

Answer 27

Resistance

Question 28

Why must you take extra caution when working around electricity?

Answer 28

Our senses cannot detect an electrical current

Question 29

How does electrical shock affect the human body?

Answer 29

Interferes with the normal electrical signals in a human body and can cause the hearts rhythm to dangerously change or to stop

Question 30

Welding burns are a example of ?

Answer 30

Ultraviolet radiation burn

Question 31

Safety around electricity involves several elements:

Answer 31

- knowing the hazards - following safe procedures - staying alert to what is going on around you - keeping the work environment clean and safe - using the necessary safety equipment

Question 32

When disconnecting a disconnect what is the proper procedure?

Answer 32

- stand on the same side as the switch - turn body away from the box - throw the switch with the non dominant hand

Question 33

Follow these steps to lock out control power:

Answer 33

- find out how and where unit is controlled. - find the disconnect that serves the area you need to service - make sure power source is not interlocked with another part of the process - of the controls are on a large console and there is a control power key, turn the key off. - if provided place key in a lockbox

Question 34

Before opening the electrical enclosure that has been locked off you must?

Answer 34

Test start

Question 35

What is the purpose of a fuse?

Answer 35

Limit maximum current flow to a safe level during a short circuit failure or heavy sustained overloads

Question 36

How does a fuse blow?

Answer 36

A fusible link is in the fuse barrel. The link melts when the current exceeds the design par-meters.

Question 37

What are some advantages of PLC’s

Answer 37

- lower overall cost - programmability - reliability - expandability