Questions and Answers
In a generator, the __________ is the support on which the stator windings are mounted.
frame
A generator converts _________ energy into electrical energy.
mechanical
When electromagnetic current runs back on itself it is called ________.
eddying
Some generators use brushes and slip rings on the rotor to pass direct current to the __________ windings.
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An AC generator is composed of __________ basic parts.
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Generators that do not use brushes or slip rings are equipped with brushless __________.
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Direct current flowing through the field windings forms __________.
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The radial clearance between the rotor and the stator is called the __________.
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In order for voltage to be generated in the stator windings, __________ must exist between the field and the conductor of the stator.
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Generators that produce three separate currents of electricity at the same time are called __________ generators.
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Which of the following is made of laminated steel and is mounted inside the frame?
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While a generator is connected to a power system, the rotor field and the stator field are basically __________.
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In Michael Faraday's experiment, as the magnet was withdrawn, a current flowed through the coil __________.
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A two pole generator will have a synchronous speed of __________ rpm.
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Which of the following characteristics of the rotating field determines the frequency of the voltage induced in the stator?
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To produce voltage, the magnetic field must be close to the __________.
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When the conductor or magnetic field moves, _________ within the conductor are forced to move from one direction to the other.
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Relative motion must occur between the magnetic field and the conductor to produce _________.
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A four pole generator will have a synchronous speed of __________ rpm.
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When a generator is connected to the power system, the __________ must be increased to produce an increase in power output from the generator.
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Increasing the main field above a value needed to maintain unit power factor will cause the voltage to lead the current and the generator to act like a __________.
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Inductive current.
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Capacitive current.
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Most instruments used to measure AC values read in __________.
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What is the number used to calculate the peak-to-peak value of a sine wave when the RMS value is known?
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Study Notes
Generator Components
- The frame is the support structure for stator windings in a generator.
- A generator converts mechanical energy into electrical energy.
- Some generators utilize brushes and slip rings to transfer direct current to field windings.
- The core of a generator is made of laminated steel and is mounted inside the frame.
Generator Operation
- In operation, the rotor field and stator field are interlocked when connected to a power system.
- A two-pole generator exhibits a synchronous speed of 3600 rpm.
- A four-pole generator shows a synchronous speed of 1800 rpm.
- Relative motion is crucial between the magnetic field and conductor for voltage generation.
Electromagnetic Concepts
- Eddy currents occur when electromagnetic currents loop back on themselves.
- Direct current through the field windings results in an electromagnet.
- When magnetic fields or conductors move, electrons are forced to shift directions.
Generator Types and Systems
- AC generators consist of two primary parts: rotor and stator.
- Brushless excitation systems replace brushes and slip rings in certain generator models.
- Three-phase generators produce three distinct currents of electricity simultaneously.
- Instruments for measuring AC values typically read in RMS (Root Mean Square).
Electrical Relations and Effects
- Increasing the main field can lead the voltage past the current, causing the generator to behave like a capacitor.
- Inductive current lags, while capacitive current leads in terms of phase relation.
- The relationship between capacitive and inductive behaviors affects energy delivery and efficiency.
Measurement and Calculations
- The peak-to-peak value of a sine wave can be determined using the square root of 2 (1.414) from the RMS value.
- The necessary electrical circumstances for stator windings include the existence of relative motion and charges.
Additional Important Concepts
- The air gap is the radial clearance between the rotor and stator, important for efficient operation.
- Prime mover power must be increased to enhance power output from the generator during operation.
- The speed of the rotating field determines the frequency of voltage induced in the stator windings.
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Description
Test your knowledge on fundamental concepts of generators with this quiz. Questions cover the components and energy conversion processes of generators. Perfect for electrical engineering students and enthusiasts alike.
