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Question
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Answer
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What do generators transform mechanical kinetic energy into?
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Electrical energy
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In simple generators, what do coils of wire rotate inside of?
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A magnetic field
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What changes as the coil rotates to produce a changing electromotive force in a generator?
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Magnetic flux
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Faraday's Law of induction states induced emf is equal to the change in magnetic flux over the ______ __ ____.
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Change in time
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The magnetic field in the stator can be produced by what other than permanent magnets?
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Electromagnets
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If the rotation is constant, what would a graph of the change in flux as a function of time look like?
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A cosine curve
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In that situation what would the graph of emf as a function of time look like?
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A sine curve
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If the induced emf is doubled, what parts of the curve also double?
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Frequency
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Amplitude
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An emf signal placed across a resistor would create an ___________ _______.
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Alternating current (AC)
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In AC generators, what connects the rotor to the external terminals?
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Slip rings
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What does a DC generator use instead?
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Split ring commutator
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What does a DC generator have the same components as?
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A DC motor
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In a DC generator, what switches sides when the emf's direction is reversed?
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The brushes
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Along with an electrical generator, what is used in wind, steam and water power stations to generate electricity?
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A turbine
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Due to its large mass, the coils in a power station generator are stationary, so what rotates?
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The electromagnets
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How many pairs of sets of coils are there in a typical power station generator?
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Three
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How many output lines come out of the generator?
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Four
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What is the last line known as?
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The ground line
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In the Tesla/Westinghouse vs Thomas Edison feud, who supported DC systems?
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Thomas Edison
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To show the danger of his competitor's system, what did Edison's company invent?
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The electric chair
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The deciding factor in the battle for power supply control was when what location was fought over for power supply?
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Niagara Falls
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Which company won the rights to the power plant?
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Westinghouse
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What do transformers change?
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Voltage
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What are the names of the two coils in a transformer?
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Primary
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Secondary
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What separates/unites the coils?
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An iron core ring
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^ is split into many layers separated by laminate, what does this prevent?
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Large eddy currents
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What supplies are transformers used in?
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AC
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What dictates whether it is a step-up or step-down transformer?
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The number of turns in the coils
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If Vp is the voltage of the primary coil, s represents the secondary coil, and n represents the number of turns in the coil, what equation shows their relationship in an ideal transformer?
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Vp/Vs=np/ns
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Due to the priniciple of conservation of energy, when voltage is increased, what is the trade-off which decreases?
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The current
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This is because of the equation P=__.
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IV
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Is it possible to have an ideal transformer?
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No
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Pp=Ps (where P is power). Therefore Vp/Vs=_____
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Is/Ip
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Other than laminas, what materials what materials can be used to prevent large eddy currents in transformers?
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Ferrites
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In an equation, power loss, P(loss)=?
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I^2R
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Massive power losses are experienced when what has a large magnitude?
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Current
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Therefore before transmission, what type of transformer is used?
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Step-up
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Where do transmission lines end and voltage is stepped down for distribution?
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Terminal stations
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What is located in almost all regional centres for power distribution?
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Zone substation
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In Australia, pole transformers drop the voltage down to what value for industrial areas?
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415V
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What is the magnitude of voltage sent to houses for domestic consumption in Australia?
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240V
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What line acts as a continuous lightning conductor and prevents faults from altering the power grid?
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The earth line
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What type of insulators prevent dry air sparks in high voltage transmission lines?
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Suspension Insulators
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What type of transformer (not stepup or stepdown) is used in household appliances for recharging devices and rectifying currents from AC to DC.
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Power-cube transformers
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