Electrical level 3 Lt. M1-M2 questions with answers

Electrical level 3 Lt. M1-M2 questions |\ |\ |\ |\ |\ |\




with answers |\




Give the two main reasons for preferring revolving-field alternators
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to revolving-armature alternators. - CORRECT ANSWERS ✔✔1.
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Higher voltages generated
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2. Higher currents can be conducted to the load
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What is the purpose of an exciter? - CORRECT ANSWERS ✔✔To
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supply DC to alternator field circuit
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Explain the construction differences between a salient-pole rotor
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and a cylindrical rotor. - CORRECT ANSWERS ✔✔Salient pole
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rotor, larger diameter, pole pieces protruding
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Cylindrical smooth faced |\ |\




What is the purpose of a field-discharge resistor? - CORRECT
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ANSWERS ✔✔Eliminate inductive back voltage created by opening
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field circuit
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, Give two reasons why a brushless exciter may be selected over a
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brush-type exciter for the field of an alternator. - CORRECT|\ |\ |\ |\ |\ |\ |\ |\ |\ |\



ANSWERS ✔✔1. When explosive or wet ambient conditions exist |\ |\ |\ |\ |\ |\ |\ |\




2. When it is necessary to have low maintenance
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Name two factors that control the frequency output of an alternator.
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- CORRECT ANSWERS ✔✔1. Rotor speed
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2. Number of field poles
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The output voltage of an alternator is maintained at a steady level
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through the use of a(n)? - CORRECT ANSWERS ✔✔Automatic
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voltage regulator |\




The voltage regulation of an alternator will be poorest with a
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__________ (high/low) power factor load. - CORRECT ANSWERS |\ |\ |\ |\ |\ |\ |\ |\



✔✔Low 0% |\




What are the three main reasons for connecting a three-phase
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alternator in wye? - CORRECT ANSWERS ✔✔1. To obtain two|\ |\ |\ |\ |\ |\ |\ |\ |\ |\



different voltages (Phase and line) |\ |\ |\ |\




2. Insulation requirements are reduced to phase values
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3. Provides neutral point for ground system
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