Questions and Answers
- An alternator is said to be over excited when it is operating at:
A synchronous motor is said to be over excited when it is operating at
The heat loss inside a straight conductor is 60J upon applying current I for 5s. If the resistance of the conductor is decreased to half, and the same current is applied for 5s, what will be the heat dissipation?
Why do we use power factor correction devices?
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If the rotor of an induction motor is rotating at synchronous speed, what is the torque?
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Cable length is 1000m, with a time of returning signal of 9.43µsec. What is the speed of wave in the cable?
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An antenna has an effective aperture of 10m². What additional information is required to determine the amplifier power?
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A 10HP single phase motor, with a 0.8 power factor, 240V, and efficiency of 0.6, what is the current?
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Which of the following is not an opportunity to do the project?
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For the shown block diagram, what is the dumping ratio O/P / I/P = U / R where S = 1?
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An alternator is operating at __________ for capacitive loads.
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Which of the following topologies can 10BaseT not be used without additional hardware conversion?
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The high voltage windings of a transformer have _________ resistivity than the low voltage side.
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The output D in the circuit is:
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The equivalent circuit of an induction machine at no load is the same as that of the transformer but with?
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Which of these is not a rule of interaction?
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Within the battery, the conventional current flow is:
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Activity on arrow needs to use dummy activities to avoid precedence problems that can happen due to:
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What is the average value of signal v(t) = 5 sin(377t)?
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A 3 phase transformer, 25MVA, 66-12.47kV, delta-wye connected, has an 8 percent impedance. On a 100 MVA, the per unit impedance is most nearly?
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And the voltage range is 0-100V. What type and magnitude of resistance is required?
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The offset of a particular segment varies from:
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The power gain of 30dB is equivalent to which amplification factor?
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Study Notes
Alternators and Synchronous Motors
- An alternator operates at leading power factor when over excited.
- A synchronous motor is considered over excited when operating at a leading power factor.
Antennas
- A micro antenna refers to a short antenna.
Project Management
- Fast track scheduling is primarily used to avoid future cost increases.
- Fast tracking in projects involves beginning work before design completion.
Architecture
- In Harvard Architecture, code and data spaces are separated.
Physics and Electrical Engineering
- The force on a moving charge in a magnetic field is perpendicular to the magnetic field direction.
- The unit of conductance is the mho.
- A transformer needs correct polarity for successful parallel operation.
- Humming in transformers is caused by the vibration of the laminated core.
Electronics
- The output of a NOR gate is HIGH when all inputs are LOW.
- The voltage gain of an amplifier with negative feedback can be calculated, where the gain without feedback is higher than with feedback.
- In a cascade amplifier, reducing loading effect requires a high output impedance from the last stage and a high input impedance for the first stage.
Thermal and Efficiency Concerns
- Minimum voltage regulation occurs at a unity power factor load.
- Heat loss in a conductor is affected by its resistance and the current applied.
Capacitors and Resistance
- For three 30µF capacitors in a star configuration, the capacitance between two terminals is 15µF.
Motors
- The slip in an induction motor at no load is less than 1%.
- An induction motor experiencing rotational motion at synchronous speed generates zero torque.
Signal Processing
- To eliminate DC offset, a high pass filter is used.
- Harmonics in a system stem from variable impedance loads, saturated magnetic loads, and power electronics.
Zener Diodes and Current Regulation
- The main function of a Zener diode is voltage regulation.
Wireless Communication
- In digital telecommunication systems, ATM provides connection-oriented service.
Miscellaneous Concepts
- The self-discharge rate of a lead-acid battery depends less on the nominal voltage.
- The Zener current maximum can be calculated given specific conditions in a Zener regulator.
Circuit Behavior and Components
- The voltage source with the most current is across two 10 Ohm resistors in parallel.
- Induction motors can use various types of braking, including dynamic and regenerative braking.
Additional Electrical Concepts
- To find the power consumption in advanced embedded systems, various factors like dynamic response must be considered.
- An alternator operating idle will be less efficient primarily due to armature losses.
Miscellaneous Calculations
- Transformer saturation affects efficiency and losses.
- The characteristics of AC circuits differ from those of DC circuits, emphasizing the importance of reactance and impedance in AC analysis.
These study notes encapsulate the core concepts and answers presented in the context of electrical and electronic engineering.### Super Heterodyne AM Receiver
- To listen to a station at 540 kHz with an intermediate frequency (IF) of 455 kHz, the local oscillator tuning frequency is 995 kHz.
10BaseT Topology Compatibility
- 10BaseT cannot be used without additional hardware conversion in a bus topology.
Transformer Resistivity
- High voltage windings of a transformer have higher resistivity compared to the low voltage side.
ACR of Conductor
- An ACR conductor with 7 steel wires and 25 aluminum wires is specified as 7/25.
Circuit Output
- The output D in a specified circuit can be calculated using the formula: D = A(B + C).
Wave Speed in Cable
- For a cable length of 1000 m and a return signal time of 9.43 µsec, the speed of wave in the cable is calculated as 0.75.
Induction Machine Equivalent Circuit
- The equivalent circuit of an induction machine at no load is similar to that of a transformer but features an open circuited secondary.
Rules of Interaction
- Etiquette, morals, communication, and ethics are not considered rules of interaction since they allow various forms of expression.
Current Flow in Batteries
- Within a battery, conventional current flows from the positive electrode to the negative electrode (C) or anode to cathode.
Precedence Problem in Project Management
- To avoid precedence problems caused by merge activities, dummy activities are utilized in arrow diagrams.
Average Value of a Signal
- The average value of the signal v(t) = 5 sin(377t) is 3.2V, calculated as V_avg = 5 * 0.636.
3 Phase Transformer Impedance
- A 3-phase transformer rated at 25MVA with 8 percent impedance has a per unit impedance of 0.32 when scaled to 100 MVA.
Resistance Requirement
- For a system with a voltage range of 0-100V, a series resistance of 1M ohm is required.
Offset Variability
- The offset of a specific segment can vary from 0000H to FFFFH.
Power Gain Calculation
- A power gain of 30 dB corresponds to an amplification factor of 1000, derived from the formula: dB = 10 log(P1/P2).
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Description
This quiz explores the concept of alternators and their operational characteristics. Understand what it means for an alternator to be overexcited and how it impacts electrical systems. Perfect for students in electrical engineering or related fields.
