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Pls 220 Flashcards

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1
Q

the full load current, or full load amp rating of any electric motor is the ______________________ it can safely draw from the line

A

max amt of current

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2
Q

where to find FLC rating on a motor

A

name plate

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3
Q

what table in the CEC is used to determine motors FLC

A

table 45

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4
Q

how to find minimum code conductor ampacity and from what code rule

A
  • multiply FLC by 125%
    -CEC 28-106
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5
Q

What table to find trade size conductors

A

T 1,2,3,4……

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6
Q

what code rule to find temperature limitations for conductors

A

CEC 4-006

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7
Q

Can trade size conductors be smaller then CEC calculated conductor ampacity

A

NO

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8
Q

Every electric motor and its branch cct require a ______________ means and some sort of __________ protection

A

-diconnecting
-overcurrent

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9
Q

What are type P fuses

A

non time delay

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10
Q

what are type D fuses

A

time delay

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11
Q

what are the 3 types of overcurrent devices

A

-type P fuses (non time delay)
type D (time delay)
-cct breakers

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12
Q

Why do motors create a surge when the electric motor starts

A

-large inrush current needed to start the electric motor

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13
Q

What code rule and table is used to size overcurrent devices

A

-CEC 28-200
-Table 29

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14
Q

What are standard trade sizes for saftey switches

A

30,60,100,200,400,600A

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15
Q

In non-fused switches the ampere rating of the load determines the _____________ size

A

disconnect switches

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16
Q

In fused diconnects, the ampere rating of the chosen fuse determines the ___________________ size

A

disconnect switch

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17
Q

What are bonding conductors used for

A

bond to ground the non-current carrying metal parts of the electric motors branch cct

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18
Q

What section of the CEC indicates about bonding and what table

A

section 10
- 10-616 1)
-Table 16

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19
Q

does the bonding conductor need to be larger then the supply conductor

A

no

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20
Q

What CEC section is used for overloads

A

26-306

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21
Q

A motor drawing more current than its FLC is ______________

A

overloaded

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22
Q

What happens if a motor is overloaded

A

-motor overheats
-burn out motor windings

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23
Q

What is the purpose of the overload device

A

-shut down the motor before its windings are destroyed

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24
Q

overload devices operate on a _______________ baisis

A

time-lags

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25
Q

what must seperate over load devices do

A

monitor and respond to motors current (proportional to winding temp) to shut down the motor

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26
Q

the bigger the over load the _____________ the overloaf device _________

A

-quicker
-opens

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27
Q

What are the types of overload devices

A

-bimetallic
-solder
-electronic

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28
Q

The max current rating of a seperate overload device is dependent on what 2 things

A

-Full load cuurent
-service factor

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29
Q

without a service factor must have overload protection calculated based on what code rules

A

115% of FLC (28-306)
140% of FLC (28-710) for hermetic motors using O/L relays

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30
Q

Describe the operating principals of a thermal overcurrent protecting device

A

-current sensitive material’
-in series with the motor
-heats ip and heat sensor trips

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31
Q

What are the advantages of electronic overloads compared to fixed thermal overloads

A

-can be dialed to specific trip setting

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32
Q

What name is assigned to the device which protects an electric motor burning out?

A

-overload

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33
Q

What is the service factor percentage multiplier for a SF of 1.15 or greater

A

125%

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34
Q

What is the service factor percentage multiplier for a SF of less than 1.15

A

115%

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35
Q

What is the service factor percentage multiplier for a hermetic motor proteccted by a overload relay

A

140%

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36
Q

For Schools/hotels/hospitals what code section do you go to

A

Section 8

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37
Q

What do hydroelectric dams use

A

a resivoir

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38
Q

How do large power utility wind terbines work

A

-use generators that produce AC b/c easier to connect the output to the transmission line.

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39
Q

What type of current do smaller wind terbines use

A

DC

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40
Q

what do wind terbine breaks do

A

-prevents wind terbine from rotating if the wind speeds are too great

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41
Q

What must be opened to completley de-energize the panelboards branch cct compartment

A

-utility diconnect switch
-diconnect switch
-BOTH!!!!!!!

42
Q

whats the most common way of producing electricity from the sun

A

photovoltaic cells

43
Q

light is made of particles called ________________

A

photons

44
Q

examples of renewable energy sources

A

-solar
-wind
-hydro power
-geothermal

45
Q

2 methods used for hydropower electrical generation? advatage and disadvantage of each

A
  1. resivoir: D, alters body of water. a, allows water to be held for later power generation
  2. gates: A, can increase/decrease water flow. D, excess water from run off
46
Q

what is the puirpose of the gearbox and break in wind terbine

A

prevents wind terbine from rotating if winds are too high

47
Q

what is the purpose of a silicon solar cell

A

produces potential difference

48
Q

What is a solar cell

A

-individual source of energy

49
Q

what is a solar module

A

-a panel that has many cells connected together to increase the output voltage and current capacity

50
Q

what is the solar array

A

many solar modules connected together to increase the voltage and current capacity

51
Q

what type of battery technology is used for most renewable energy storage systems?

A

lead-acid

52
Q

What function does the charge controller serve in a battery storage system?

A

-prevents batteries from being damaged from over charging
-done by limiting current and voltage of battery

53
Q

what are stand alone solar systems

A

-not connected to the power grid or use a back-up generator must have enough capacity to supply max exited load

54
Q

the amount of power required to be supplied by the stand alone solar system deoends on what

A

electrical load connected to the system

55
Q

for solar systems what is the total watt-hours/day multiplied by to compensate for all the systems innefficiencies

A

multiply by 1.25

56
Q

The size of a battery bank for solar _____________ the more times its completley discharged

A

decreases

57
Q

What is an AC module

A

-A complete emviromentally protected assembly of interconnected solar cells
-generates AC power from sunlight

58
Q

What is an array

A

-assembly of photovolataic modules with a support structure and foundation,tracking and other things required to form a power-producing unit

59
Q

What is a bipolar system

A

-a solar photovolataic system with 2 monopole photovoltaic source or output ccts has an opposite polarity to a common refrence point or centre tap

60
Q

What is a charge controller

A

-equipment controlling DC voltage or current or both
-charges a battery or other storage device

61
Q

whats an interactive system

A

-a power production system that operates in //
-can deliver power to another system such as a supply authority system

62
Q

whats an inverter-combination inverter/power conditioning unit

A

-used to invert DC into AC at a fixed voltage and frequency in a stand-alone system or following wave form in a utility interactive system

63
Q

whats a power conditioning unit

A

-used to change voltage level or waveform or alternating or regulate a power sources output

64
Q

what is a utility-interactive inverter

A

-used in // with an electric utility and uses prevailing line voltage frequency on the utility line as control preamiter
-ensuring that the renewable energy systems output is fully synchronised with the utility power

65
Q

what is a monopole

A

-an array or portion of an array with 2 source cct conductors
-one + and one -

66
Q

what is a nacelle

A

-the body,shell, and casing covering the gearbox, generator, blade hub and other parts mounted on the top of a tower structer of a propeller-type wind terbine and electronically connected to the rest of the wind terbine generator electrical system after instillation

67
Q

what is a photovoltaic combiner

A

-an assembly of buses and connections that may have over current devices,control apparatuses, switches or others connected to a photovolatic source cct or outputs of other combiners to create an output at higher current or voltage or both

68
Q

what is a photovoltaic module

A

-a complete, enviromentally protected asssembly of interconnected solar cells

69
Q

what is a photovoltaic output cct

A

-cct conductors between the photovoltaic source ccts and the power conditioning unit or DC utilization equipment

70
Q

what is a point of common coupling

A

-point where the supply authoritys system is connected to the power producers facilities or conductors

71
Q

what is rated power on a small wind turbine

A

-max power output at a wind speed of 11m/s or less

72
Q

what is renewable energy

A

-energy from resources that are naturally replenished
-like sun,wind,water

73
Q

what is a solar cell

A

-the basic photovoltaic device that generates electricity when exposed to light

74
Q

what is a solar photovoltaic system

A

-all the comonents and subsystems that convert solar energy into electrical energy sutible for connection to a utlization load

75
Q

what is a stand-alone system

A

-system that supplies power independantly of a supply authorys network

76
Q

what is a supply conductor

A

-conductor used to connect the system to its electrical point of delivery

77
Q

what is a tower for wind terbines

A

-a pole or other structure that supports a wind turbine

78
Q

what is a wind-large wind system

A

-system that has 1 or more wind turbines
-rated power output exceeds 100kW

79
Q

what is a small wind system

A

-system that has one or more wind turbines with a rated output up to and including 100kW

80
Q

what is a wind turbine

A

-mechanical equipment that converts wind kinetic energy into electrical energy

81
Q

what is the wind turbine generator

A

-all electrical equipment and ccts within the wind turbine structure to the point of coupling to the load or grid

82
Q

what code section do you find renewable energy

A

section 64

83
Q

the sum of the current ratings of overcurrent devices in ccts supplying power to a busbar or conductor can exceed bus bar or current rating by a max of ____________% in non residential. what code rule for non residential to find this

A

120%
-64-112(4c)

84
Q

in residential the supplying power to a busbar or conductor can exceed busbar conductor rating to a max of _______________%

A

125%

85
Q

what is corrosion

A

an electrochemical reaction where metals oxidize

86
Q

when do metals corrode

A

-when they are in the presence of an oxidizing agent

87
Q

what is the most common oxidising agent

A

oxygen

88
Q

an atom ____________ an electrical charge when it contains the same number of electrons and protons

A

does not have

89
Q

when an atom loses one or more electrons it becomes __________

A

positibve because has more positibe protons

90
Q

oxidisation occurs when an atom _____________ one or more electrons

A

loses

91
Q

What 2 things are needed for corrosion to occur

A
  1. oxidising agent
    2.reducing agent
92
Q

the more _____________ the reduction potential, the less likely the element is to oxidize

A

positive

93
Q

the more _______ the reduction potential, the more likely the element will oxidise

A

negative

94
Q

what are 2 types of corrosion

A

1.standard corrosion, in a single type of material
2. galvanic corrosion, caused by joining 2 dissimilar metals together

95
Q

for standard corosion what does the small potential difference cause

A

-allow current to flow from a more negative area to a more positive area in the piece of iron

96
Q

what is commonly used to protect steel

A

zinc, done by applying a thin coating of zinc over the steel

97
Q

what happens when zinc corrodes

A

-creates a protective coating of zinc oxide which prevents water molecules from reaching the zinc and iron in the steel.

98
Q

what is steel with zinc coating called

A

galvinized steel

99
Q

when does galvinized corrosioon occur

A

-when 2 dissimilar metals are connected in the presence of an electrolyte like water
-the metal with the lower reduction potential oxidizes, giving up its electrons to the other material with the higher reduction potential

100
Q

What enchances corrosion

A

-electrolytes
-acids
-temperatures

101
Q

an ______________ in temperature causes an increase in corrosion

A

increase

102
Q

corrosion rate doubles for every ___________ in temperature

A

10 degrees celcius increase

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