UPDA Electrical/Electronic Engineering Review 01

Alternators and Motors

• Alternator Over Excitation: Operating in a leading power factor.
• Synchronous Motor Over Excitation: Also operates in a leading power factor.
• Induction Motor Torque at Synchronous Speed: The torque is zero.

Antennas and Capacitors

• Micro Antenna: Refers to a short antenna.
• Capacitance Calculation: For three 30µF capacitors in a star formation, the capacitance between two terminals is around 15µF.

Project Management

• Fast Track Scheduling Purpose: To minimize future cost increases rather than just reducing construction costs.
• Fast Tracking Defined: Initiating a project before completing the design phase.
• Float in Project Management: Refers to the amount of time that a task can be delayed without affecting the overall project timeline.

Signal and Systems

• Digital Telecommunication: Connection-oriented service is best provided by technologies such as ATM.
• Wattage Calculation: For an AC current scenario, the formula used involves both DC and AC components, yielding wattage outcomes based on effective current.

Electrical Principles

• Unit of Conductance: The unit is called mho.
• Conductance of Circuit: Noted for resistors in combinations such as series and parallel.
• Transformer Saturation: Results in high efficiency and significant no-load losses.

Filters and Feedback

• Use of Filters: High pass filters are used to eliminate DC offset.
• Feedback in Amplifiers: Negative feedback reduces gain but enhances stability and linearity of an amplifier.

Zener Diode and Electrical Components

• Function of Zener Diode: Primarily used for voltage regulation.
• Power Requirements: Calculations for supply resistors and diode power ratings consider variations in conditions such as load current.

Current and Resistance

• Current Rating in a Circuit: Defined based on voltage and resistance using Ohm’s law.
• Resistivity Comparison: High voltage side transformers typically have higher resistivity than low voltage sides.

Operational Characteristics

• Voltage Gain without Feedback: A 9% feedback reduces the apparent gain of the amplifier.
• Induction Motor Braking: Methods include regenerative and dynamic braking techniques to reduce the stop time effectively.

Miscellaneous Electrical Concepts

• VSWR (Voltage Standing Wave Ratio): Indicates the measure of efficiency in a transmission line. Higher ratios signify mismatched impedances.
• Heat Loss in Conductors: Describes energy loss proportional to the square of the current and resistance.

Project Scope and Management

• New Scope of Work: Engineers should inform their supervisors about new projects not included in initial scopes before proceeding.
• Rating of Cable Insulation: Must consider environmental factors for marine applications.

Important Equations

• H (Magnetic Field): H = I / (2πr) defines field intensity from a current-carrying conductor.
• Power Consumption in Embedded Systems: Typically noted around 10-80% depending on system requirements.

Resources in Electrical Systems

• Resistor Combinations: Understanding parallel vs. series resistances will yield different equivalent resistances.
• Signal Amplification in Wireless Systems: A low-noise amplifier is essential for enhancing weak received signals effectively.

This summary captures key concepts and principles, providing a concise overview for study in electrical and electronic engineering without overwhelming detail.### AM Receiver Tuning Frequency

• For a super heterodyne AM receiver with an IF of 455 kHz tuned to a station at 540 kHz, the local oscillator frequency is 995 kHz.

10BaseT Topology Compatibility

• 10BaseT cannot be used with a Bus topology without additional hardware conversion. It is compatible with Star, Tree, and Point-to-Point topologies.

Transformer High Voltage Windings

• High voltage windings of a transformer have higher resistivity compared to low voltage windings.

ACR of Conductors Specification

• A conductor with 7 steel wires and 25 aluminum wires is specified as 7/25.

Circuit Output Expression

• The output D in the circuit can be expressed as (A+B)(B+C).

Speed of Wave in Cable

• For a cable length of 1000m with a return signal time of 9.43 µsec, the speed of wave propagation in the cable can be calculated using the formula speed = distance/time.

Induction Machine Equivalent Circuit

• The equivalent circuit of an induction machine at no load is the same as that of a transformer with an open circuited secondary.

Rules of Interaction

• Etiquette, Morals, Communication, and Ethics are considered rules of interaction; "Law" is not typically included.

Battery Current Flow

• Within a battery, conventional current flows from the positive electrode to the negative electrode.

Precedence Problem in Activities

• Dummy activities are needed to avoid precedence problems that occur due to burst activities.

Average Value of a Signal

• The average value of the signal v(t) = 5 sin(377t) is approximately 3.2V.

3-Phase Transformer Impedance Calculation

• For a 25MVA, 66-12.47kV delta-wye connected transformer with 8% impedance, the per-unit impedance on a 100 MVA base is approximately 0.32.

Resistance Requirements in Circuit

• To achieve a voltage range of 0-100V, a series resistance of 1M ohm is required based on the provided hint.

Offset Variations

• The offset of a particular segment can vary from 0000H to FFFFH.

Power Gain and Amplification Factor

• A power gain of 30 dB corresponds to an amplification factor of 1000, calculated using the formula dB = 10 log(x).