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Electrical Level 3 and 4 > EPS AND RES > Flashcards

EPS AND RES Flashcards

1
Q

Batteries convert _____ energy into _____ energy

A

Chemical

Electrical

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2
Q

When several cells are connected together this equals a ?

A

Battery

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3
Q

The output of a battery depends on?

A

Material within

How they are connected

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4
Q

Each battery cell is made of two different materials called?

A

Electrodes

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5
Q

The battery electrodes are immersed in a conductive liquid called?

A

Electrolyte

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6
Q

When cells are connected in series a higher _____ is achieved?

A

Voltage

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7
Q

When cells are connected in parallel a higher ______ is acheived?

A

current

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8
Q

Batteries are rated in ?

A

Voltage and Ampere-hours (Ah)

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9
Q

Primary cell energy comes from?

A

Consuming electrodes (no re-charge)

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10
Q

Secondary cells also called ____ ____ have no _________ and must be _______.

A

Storage cells
Energy at the beginning
Charged

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11
Q

Large capacity rechargeable batteries are called?

A

Wet cells

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12
Q

Recharging of secondary cells is done by ?

A

Passing current through in the opposite direction of discharge

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13
Q

All batteries have _______?

A

Internal resistance

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14
Q

Open circuit voltage is ?

A

No-load terminal voltage

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15
Q

Charged battery chemical reaction

A

Lead Dioxide + Sulphuric Acid

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16
Q

Discharged battery chemical reaction

A

Lead Sulphate + Lead Dioxide + Water

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17
Q

The lead sulphate causes the internal resistance to increase during and when the battery is discharged, this is called?

A

Sulphation

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18
Q

The amp hour spec provides a measurement of battery ?

A

Capacity or how much energy can be stored by the battery

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19
Q

A dead battery voltage is considered to be ?

A

10.5V

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20
Q

Another measurement of battery capacity is?

A

Reserve Capacity

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21
Q

Reserve capacity is the number of ______ a battery @____C can supply a _____A load until it’s voltage drops to ______VPC

A

Minutes
20C
25A
1.75VPC

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22
Q

The __________ spec provides a measurement of the starting power of a battery at -18C under a load for 30 seconds with the end voltage maintained at 1.20VPC.

A

Cold Cranking Amps

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23
Q

Start batteries are manufactured with _____ plates which can convert chemical energy to electrical energy much _____ than deep cycle.

A

Softer

Faster

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24
Q

Deep cycle batteries do not work well for ______ applications because they are constructed with _____ plates for lengthy discharge times.

A

Starting

Hard

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25
Q

Marine cranking amps is similiar to cold cranking amps bit is performed at a _______ instead of -18C

A

Warmer 0C

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26
Q

For any specific battery the MCA will be about ___% greater than the CCA.

A

20%

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27
Q

Separators are used between plates of lead acid batteries to prevent?

A

Short circuits

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28
Q

Ribs at the bottom of lead acid batteries are used to?

A

Catch shed material from the plates

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29
Q

List 3 types of lead acid batteries?

A
  1. Flooded or Wet type
  2. Gel cells
  3. AGM (Absorbed glass mat) cells
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30
Q

Charging process

A
  1. Run a current through the battery in the opposite direction, the chemical action is reversed
  2. The plates go back to their original material and the electrolyte gets stronger
  3. For a 12V battery, charging V is usually 14.2V to 14.5VDC
  4. During charging, hydrogen gassing may occur through vents
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31
Q

To determine the level of charge in a battery we check the?

A

Specific gravity (SG) of the electrolyte

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32
Q

Specific gravity is the measure of?

A

The amount of acid contained in the water

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33
Q

Water has a SG of _____ and a _____ is the tool used to measure?

A

1.000

Hydrometer

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34
Q

Fully charged battery SG and open circuit voltage?

A

1280 or 1.28 … 12.7V open circuit

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35
Q

Fully discharged battery SG and open circuit voltage?

A

1150 (1.15) or less … 11.9V open circuit

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36
Q

SG readings should be taken at ____ C

A

25C

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37
Q

When the temp falls we ____ our SG readings and when the temp rises we ____ our SG readings.

A

Decrease

Increase

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38
Q

For each degree away from 25 we increase or decrease our SG reading by ____

A

0.7

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39
Q

High ambient temp battery operating specs

A

Reduced life and voltage

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40
Q

Low ambient temp battery operating specs?

A

Shelf life increases

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41
Q

The plates in a battery should always be covered with?

A

Electrolyte

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42
Q

When mixing electrolyte, always add ___ to the ____?

A

Acid to the water

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43
Q

Batteries should be cleaned with?

A

Baking soda and water

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44
Q

Nickel-Iron (Ni-Fe) Battery pros

A

Robust (virtually indestructible)
Long battery life (+30 years)
Used in mining operations
Environmentally benign

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45
Q

Nickel-Iron (Ni-Fe) Battery cons

A

Hard time keeping a charge
Bulky
Very expensive to make
Operates poorly in low temps

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46
Q

How to test a Nickel-iron battery?

A

Use a DC volt meter on cells while under load to determine state of charge (can not use hydrometer as the electrolyte density never changes)

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47
Q

Nickel-Cadmium Battery cons

A

Suffer from “memory effect”

Cadmium is a disaster environmentally

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48
Q

Lithium-Ion Battery benefits

A

High energy density
Tiny memory effect
Low self discharge
Comes in many shapes and sizes including lightweight options

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49
Q

(Charging Terms) Initial

A

First charge after battery is filled with electrolyte

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50
Q

(Charging Terms) Normal

A

Restores battery after it has been used or sitting

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51
Q

(Charging Terms) Trickle

A

Maintains battery fully charged with no load connected

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52
Q

(Charging Terms) Float

A

Supplies charge to batteries and connected loads

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53
Q

(Charging Terms) Bulk

A

Restores battery after deep discharge (constant current)

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54
Q

(Charging Terms) Absorption

A

Ensures plates are de-sulphated after bulk (constant voltage)

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55
Q

(Charging Terms) Equalization

A

Elevated charge voltage to equalize cells and remove residual sulphation

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56
Q

Constant current

A

Outputs rated current allowing charge to build fast
Voltage increases as charge builds
Preferred method for nickel cadmium

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57
Q

Constant Voltage

A

Outputs preset voltage level to prevent over charging
Current decreases as charge builds
Used for “basic” charging of lead acid batteries

58
Q

Stand alone AC PV systems include an?

A

Inverter

59
Q

High quality inverters can give conversion efficiencies of ___ %

A

90

60
Q

For a hybrid system what is the most common back-up?

A

Diesel or propane generator

61
Q

Two mai types of grid connected PV systems?

A

Utility interface

Utility Interactive

62
Q

Utility Interface specs

A

Solar energy is stored in battery bank
Provides some or all of buildings electrical needs
Low batteries = building transfer to utility

63
Q

Utility Interactive specs

A

No storage

Excess energy fed to utility grid

64
Q

What is Islanding?

A

The undesirable condition where a distributed generation power source such as a PV system, continues to transfer power to the utility grid during a utility outage.

65
Q

Three factors that determine any PV modules power output?

A
  1. Load impedance
  2. Solar Irradiance
  3. Cell Temperature
66
Q

Meter bases

A

4-jaw: single phase
5-jaw: single phase but has 5th connection for neutral
7-jaw: 3 phase

67
Q

Modern inverter two types?

A

Modified square wave

Sine wave

68
Q

What kind of modern inverter is seen on PV systems?

A

Modified square wave (cheaper than sine wave, not as efficient)

Notes: cause more harmonic distortion, sine wave inverters will cost 2 to 3 times as much but are superior

69
Q

What is a Pyranometer?

A

is used to measure solar irradiance on a planar surface and is a sensor that is designed to measure the solar radiation flux density from a field of view of 180 degrees.

70
Q

What is a Pyrheliometer?

A

an instrument used for direct measurement of solar irradiance

71
Q

What three things should you check for when you first receive a new generator?

A

Intake sealed
Exhaust sealed
Coolant intact

72
Q

For servicing a gen-set do not rely on the OFF button of the ATS, you should?

A

Remove the battery cable from the start battery (negative first)

73
Q

Starting KVA for a motor =

A

Locked rotor KVA

74
Q

“Stand by” power systems come in three forms?

A

Dual radial feeds
Batteries and UPS
Emergency Generators

75
Q

Generators can be started then switched to critical loads using an?

A

Automatic transfer switch (ATS)

76
Q

ATS typically take __ - __ seconds to bring “online”

A

8 to 15

77
Q

Generator fuel options?

A

Propane - bad w/ extreme temps
Gasoline - faster start (8s) time but unstable
Diesel - most popular, slow start (12s)

78
Q

Generator connections are typically?

A

Three phase, 60Hz and almost all incorporate a 4-wire grounded neutral

79
Q

Generators should be installed?

A

As close as possible to main power supply
On vibration pads
Not in areas of abnormally high/low temps
With adequate fuel for outages and exercising

80
Q

AVR =

A

Automatic Voltage Regulator

81
Q

What 4 things must be the same for generators to parallel?

A
  1. Terminal voltage
  2. Frequency
  3. Phase sequence
  4. Phase displacement
82
Q

Synchronized generators must have what type of protection?

A

Reverse Power Relays (RPR)

83
Q

Generators should be run for at least ___ minutes/week and is preferred to do so under __% load

A

30mins

40% load, full if possible

84
Q

What does exercising a generator accomplish? (6 things)

A
  1. Booster charge to the batteries
  2. Cleans carb sediment
  3. Keeps all parts lubed
  4. Brings engine up to operating temp
  5. Removes any condensation from crankcase
  6. Restores residual magnetism
85
Q

During the exercising period of a gen, observe and record?

A 
Oil pressure
Battery charging ammeter
Fuel level
Voltage and current levels
Frequency under load
Crank time
86
Q

Transfer switches are ____ before _____

A

Break before make

87
Q

The purpose of a transfer switch is to?

A

Switch the load from normal supply to emergency power either manually or automatically

88
Q

What type of transfer switch would be used when a load could be affected by a slight bump in the line when transferring power?

A

Closed transition transfer switch (CTTS)

89
Q

Typically a PV cell has an efficiency of?

A

20% or less (converted into electrical energy)

90
Q

When paralleling generators if the lights are flashing out of sync what does this indicate and how is it rectified?

A

Wrong phase sequence

Interchange 2 leads of incoming alternator or change direction of prime mover

91
Q

When paralleling generators if the lights are flashing at the same time but very fast what does this indicate and how is it rectified?

A 
Incorrect frequency (too low).
Changing the primer mover speed (DC motor excitation)
92
Q

When paralleling generators if the lights stay on dim to bright what does this indicate and how is it rectified?

A

Phase displacement off.

Tweak the excitation of the primer mover to change the position within the revolution.

93
Q

When paralleling generators and they lights are fully on bright or dim what does this indicate and how is it rectified?

A

Voltage does not match.

Adjust the field excitation of the alternator

94
Q

Paralleled alternators share KW by varying the ______ and share KVARS by varying the _______?

A

Power of the prime mover

Field excitation of the alternator

95
Q

What is “hunting”

A

Surging or oscillating of power between 2 alternators

96
Q

How can “hunting” be rectified?

A
  1. “Damping” the governor
  2. Heavy fly wheels
  3. Amortisseur windings
97
Q

The difference between a primary cell and a secondary cell is?

A

Secondary cell is rechargeable, primary is not

98
Q

To determine the state of charge for a lead acid battery, could use a?

A

Voltmeter with a load connected to the battery

99
Q

The no-load terminal voltage of a fully-charged, 6 cell lead acid battery would measure as?

A

13.2V

100
Q

The internal resistance of a storage battery will _______ during charging?

A

Decrease

101
Q

“Sulfation” is most likely caused by?

A

too low of water level

102
Q

What type of genset is usually used with microhydro and wind power?

A

Asynchronous

103
Q

Pressure x volume power lost at a PRV can be recovered by replacing the valves with a ?

A

Pump as a Turbine (PAT)

104
Q

A _______ is essential for disconnecting the turbine in the event of loss of grid or phase (hydropower)

A

Intelligent relay

105
Q

Advantages of hydro kinetic power?

A
  1. More predictable output than wind power
  2. No retaining structure
  3. Discreet or invisible due to the turbine components near total immersion
106
Q

Disadvantage of hydro kinetic power?

A

Winter operations problematic

107
Q

3 Main types of hydro kinetic turbines?

A
  1. Vertical axis
  2. Horizontal axis
  3. Oscillating-foil
108
Q

5 types of renewable energy?

A 
Sunlight
Wind
Hydro
Tides
Geothermal heat
109
Q

A wind turbine is a rotating device used to convert?

A

Kinetic energy into electrical energy

110
Q

2 types of wind turbines?

A

Horizontal axis

Vertical axis

111
Q

The electrical machine of a wind power source is basically a ?

A

SCIM

112
Q

A doubly fed induction machine is basically a ?

A

WRIM

113
Q

A doubly fed induction generator has very good?

A

Efficiency

114
Q

What strategies are employed to extract maximum power from the wind?

A

Blade pitch control
Variable pulley drive
Doubly fed induction generator

115
Q

The nacelle is equipped with two devices to keep account of its angular position?

A

A turn counter

A limit detector

116
Q

What is the purpose of an accumulator?

A

Store energy and be can used to supplement and regularize the flow rate of a pump

117
Q

Wind power brake systems?

A

Rotor brake = hydraulic released, spring applied

Yaw brake - hydraulic applied, spring released

118
Q

What does an Anemometer do?

A

Wind speed monitor

119
Q

What are the 2 purposes of a UPS?

A
  1. An electrical apparatus that supplies emergency power to a load when the input power source or mains power fails.
  2. Enhance the quality of regular power by providing surge suppression and filtering noise
120
Q

Off-line UPS specs

A

UPS is in “stand by”
Inverter not in primary path to the load normally
Time delay in the switching operation (2-12msec)
Very inexpensive

121
Q

On-line UPS specs

A
  • Batteries always connected to inverter = no power transfer switch.
  • Charger/converter larger
  • Units larger and generate more heat
  • Shorter lifespan for unit and batteries
122
Q

What is the simplest and most economical UPS?

A

On line UPS with no bypass

123
Q

Ferro-Resonant UPS specs

A
  • Same as off-line but when AC fails a special detector circuit switches inverter on and opens transfer switch
  • This transformer essentially holds energy long enough to cover transfer time = eliminates it
  • Transformer filters output
  • Limited to 15KVA
124
Q

Line interactive UPS specs

A
  • Power is normally taken from utility with more active filtering for better waveform output
  • Similar to off-line but utility power fed through tap-changer
  • Tolerates continuous under voltage brown outs and over voltage surges without consuming battery reserve
125
Q

Rotary UPS specs

A
  • Uses high inertia of flywheel provide short term power in event of power loss (15-40sec) until generator picks it up
126
Q

Rotary UPS advantages?

A
  • High current output
  • Long lasting (30 + years)
  • Provide PF correction
127
Q

Rotary UPS disadvantages?

A
  • Expensive and much larger
  • Maintenance required and extensive
  • Can not be hot swapped
128
Q

All UPS provide protection from surges, spikes and noise using a ?

A

Metal Oxide Varistor (MOV)

129
Q

Second line of defence for a UPS?

A

Static bypass switch

130
Q

Good field practice is to ______ bypass the UPS first then _____ bypass

A

Internal

External

131
Q

Internal resistance of a battery increases due to?

A

Sulphation

132
Q

What batteries are pressurized?

A

AGM and sealed lead acid

133
Q

A fully charged lead acid battery has ___ V per cell and a hydrometer would measure ____ specific gravity and would freeze around ____ C

A

2.2V
1280
-60C

134
Q

A lower depth of charge battery means the battery is ____ charged?

A

More

135
Q

Which battery rating gives the best indication of how much energy it stores?

A

Amp-hours

136
Q

After maintenance, the battery charger should be set to?

A

Equalization

137
Q

The charging state where the battery is at a voltage where it will have the longest lifespan is?

A

Float/trickle

138
Q

2 timed stages when normal power is restored?

A
  1. Ensure NP is returned to stay

2. Engine cool down

139
Q

When is the electrical brake solenoid on the transfer switch on?

A

Only during load transfer

140
Q

Another device used for synchronizing alternators which uses a single needle indicator influenced from a coil connected to each alternator is called?

A

Synchroscope

141
Q

What is home portable generators commonly referred to as?

A

Back up power

142
Q

What is the difference between a “nonseparately derived system” and a “separately derived system”?

A

The neutral is disconnected by the transfer switch on a separately derived system and must be re grounded.

Electrical Level 3 and 4 (10 decks)

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