Power Pro Book 2 Flashcards
Everything in the universe is made up of?
Matter
What is the smallest unit a compound can be broken down into without changing characteristics of the compound?
Molecule
What is the purest part of a substance that can be broken down and retains its properties as that element?
element
What are the three parts of an atom?
Proton, Neutron and electron.
How many free electrons do conductors have in the valence shell?
1 to 3
In contrast to good conductors, we consider substances that have how many free electrons be insulators?
Between 5 to 8
Semiconductors are not good conductors or insulators and are made of substances that have how many free electrons?
4
What symbol do we commonly use to represent restistance?
Greek letter Omega (Ohm)
When it comes to resistance in a piece of wire, what does the smaller surface area cause?
Higher Resistance
What type of voltage normally maintains the same magnitude, but may vary?
DC, Direct Current
What type of voltage continually changes magnitude and occasionally changes direction?
AC, Alternating Current
Ohm’s Law describes the relationship between?
Voltage, Current and resistance
What is the relationship of current based on Ohm’s Law?
Inversely proportional to voltage and directly proportional to resistance
What device allows you to control a direct DC circuit manually?
Switch
Which DC circuits have only one path for electron flow?
Series
*****What method of calculating total resistance of a parallel circuit only works when calculating two resistors?
Product over sum method
What type of DC circuit has more than one path for current to flow but have at least one resistor that receives the total circuit current passing through it?
Series-Parallel circuit
What is the characteristic for total power in a series parallel circuit?
Sum of the power at each individual resistor.
What type of circuit typically has a parallel circuit with one or more legs having series portions?
Combination circuit
When you hear about the frequency of electricity, it refers to the number of complete cycles that occur in?
1 second
In an AC voltage signal, how many peaks does each cycle have?
2
What component does a magnetic field have little to no influence on?
Resistors
A good example of a use for a variable resistor is a?
Dimmer switch for a light.
What do we call the induced voltage that moves in the opposite direction as the applied voltage in an inductor?
Counter electromotive force. (EMF)
What AC characteristic causes an opposition to any change in current flow?
Inductance
What component may increase or decrease voltage in a circuit?
Transformer
If the secondary coil of a transformer has less coil turns, what does the transformer do to meet circuit needs?
Steps the voltage level down
What type of transformer only uses a secondary coil?
Potential
If the secondary coil of a transformer has more coil turns what does the transformer do to meet circuit needs?
Steps voltage up
What is the insulating material called that separate the two plates of conductive material in a capacitor?
Dielectric
What AC characteristic causes an opposition to any change in value of voltage?
Reactance
Since most of the capacitors you will see have a rating much lower that one farad, what do we refer to these as, represented by µF
Microfarad
Which mnemonic spells out the phase shift in an AC circuit?
ELI the ICEman
What do we call the power created by inductance or capacitance?
Reactive power
What is the bias of a diode when we connect the positive terminal of the battery to the P-type material and the negative terminal of the battery to the N-type material?
Forward Bias
How much resistance does a diode offer to the current flow when the power source connects in the forward bias direction?
Low
In reference to reverse bias, what happens when the majority carriers move outward allowing the barrier voltage to increase?
Increase in the depletion region
What are the four basic types of wiring diagrams used in the power production field?
One-line, schematic, connection and interconnection diagram
Which diagram shows the connection of an installation or its component devices and equipment?
Connection
Which diagram provides complete wire numbers, plug and jack pin umbers, and cannon plug numbers required to completely extract and troubleshoot specific circuits.
Connection
What do dot-dash lines mean on an interconnection diagram?
Outline the panel sections
What diagram should include all wire numbers, device code numbers, and area desigations?
An extraction
Which diagram is the most important of all diagrams because it is your guide through the connection diagram?
Schematic
Typical electrical system engines use what voltage batteries to provide power to start and operate the engine?
12 or 24
Which electrical system component performs two functions-one mechanical and one electrical?
Starter solenoid
Which component is stationary conductor on the battery-charging alternator?
Stator
How many diodes are used in the rectifier of a battery-charging alternator?
6
What causes the crank relay coil to de-energize causing the starter solenoid to de-energize?
Speed switch opening
Why do you make sure to reconnect the electrical leads to the appropriate lugs to match the polarity of the battery?
To avoid damage to the battery and other electrical components
What will happen if you adjust a battery-charging alternator too high?
battery will be damaged
What will happen if you adjust a battery charging alternator too low?
Battery will not reach full charge
What is the specific gravity of a fully charged lead-acid cell at 80 degrees?
1.280
In addition to elbow length rubber gloves and a rubber apron, what other safety equipment must you wear when working on batteries?
Face-shield
what is the specific gravity of battery electrolyte changes?
+/- .004 for every 10 degrees in temperature change
Visually check the electrolyte level in each cell of a battery. If the level is low, fill the cell to proper level using
Distilled water
What is the first step you take when replacing a battery?
Disconnect the negative terminal
When replacing a battery, which step helps prevent corrosion?
Ensure battery terminals are seated and tightened
What is the first step in the troubleshooting process?
Perform ops check
Which electrical malfunction do positive and negative conductors making direct contact cause?
Direct short
Which electrical malfunction is caused by the contacts of a switch or relay being welded closed?
Shorted control
Which electrical malfunction has the same symptoms as a direct short?
Ground
What is the primary reason for engines failing to start?
Low battery voltage
One indication that a DC charging system is not working correctly is the battery-charging.
Ammeter is reading in a discharged state.
Where does a magnet have the greatest amount of magnetism?
At each end of the magnet. (Both poles)
What is the small amount of magnetism that remains in an item after removing the magnetic field?
Residual
Which alternator component offers a slight magnetic force that aligns the main magnetic field so it remains most effective?
Interpoles
Which alternator component helps the generator maintain a stable voltage under varying load conditions?
Damping windings.
What type of cores do most exciters use that retain residual magnetism?
Soft Iron
What does a voltage regulator sense if it decreases the current to the exciter field windings causing the magnetic field to get weaker?
An increase in voltage level.
Which type of alternator consists of rotating magnetic field and single set of stator coils?
Single phase
Which alternator configuration has three legs that all connect in the middle?
Wye
What is the multiplier you use to determine the line voltage if you know the phase voltage?
1.73
Which alternator configuration has no neutral that is common to all three phases?
Delta
In a rotating rectifier test, what does it indicate if a diode has a low reading in both directions?
Shorted
Which test instrument do you use when testing the main rotor leads?
Multimeter set to ohms
Which component is used with a voltmeter for a three-phase alternator to save money?
Selector Switch
Which meter indicates the true power load in an AC circuit?
Wattmeter
On the power factor meter, what will an inductive load cause?
Current to lag voltage
What devices provide variable amounts of resistance to provide a circuit with different levels of output?
Rheostats
When you inspect the voltage regulator vibration dampeners, look for
Cracking and deterioration
Where should you look for any sings of rubbing on an exciter?
Between the rotor and stator
What color will a transformer turn if it gets too hot?
Dark gray or black
Which type of circuit breaker responds instantaneously when an excess of current flows through the breaker?
Magnetic
Which relay component provides a constant restraining force keeping the armature in the normal, (deenergized) position?
Spring
Which relay component is completely self-contained and has no moving parts?
Solid-state
The closing assembly of a circuit breaker usually consists of
Closing coil/motor and control switch
Which ohmmeter reading indicates that fuse is good and no further testing is necessary?
zero
In what type of weather can a static charge can be most hazardous?
Dry, Cold weather
At what voltage can static charges ignite gasoline fumes?
1,500
What function do static grounds serve?
To dissipate or reduce unwanted electrical charges in hazardous areas to ground
What function do equipment grounds serve?
To connect all noncurrent carrying metal parts of an electrical system to ground.
When installing a star ground, what is the best approach to lower resistance and reactance at the same time?
Increase the number of conductors while keeping their lengths short
Why is it important to use straight conductors when installing rounds because a curved conductor?
Can cause inductance
Before making a ground connection to a water pipe, check for the
Presence of electric current
The purpose of bonding the generators neutral and ground is to,
provide a path for electricity to ground in the event of a fault
You will bond the generator’s neutral and ground if you are providing-
Prime power generation and a standby generator with a switch neutral
Which automatic transfer switch control sends a signal to transfer the load to generator power?
Transfer control
When conducting a visual inspection of an automatic transfer switch, what should you do if you find problem with a component
Replace it immediately
What automatic transfer switch adjustment could be set to zero if the generator has a built-in shutdown timer?
Engine shutdown delay
When installing an automatic transfer panel, what do you have to ensure when double-checking your work?
Ensuring phase rotation is correct and all connections are tight.
