Three Phase Technology in Traction Applications

<p>By adjusting the amplitude and phase of the modulated voltage (B)</p> Signup and view all the answers

<p>To define rules for varying working conditions (A)</p> Signup and view all the answers

<p>Overseeing health and operations of major components (D)</p> Signup and view all the answers

<p>Low power to weight ratio (C)</p> Signup and view all the answers

<p>High harmonic injection into the power supply (C)</p> Signup and view all the answers

<p>They are robust and require little maintenance (B)</p> Signup and view all the answers

<p>It allows for gradual stop without additional energy loss (A)</p> Signup and view all the answers

<p>To reduce energy bills and save energy for national causes (A)</p> Signup and view all the answers

<p>Three phase technology offers better adhesion for hauling heavier loads (D)</p> Signup and view all the answers

<p>It decreases (B)</p> Signup and view all the answers

<p>Current source inverter (D)</p> Signup and view all the answers

<p>To convert AC to DC (A)</p> Signup and view all the answers

<p>Regenerative and rheostatic braking (A)</p> Signup and view all the answers

<p>High torque is required below base speed (D)</p> Signup and view all the answers

<p>The voltage-to-frequency ratio (v/f) (C)</p> Signup and view all the answers

<p>A main transformer and a filtering stage (A)</p> Signup and view all the answers

<p>The design of the inverter circuit (A)</p> Signup and view all the answers

<p>2.0 to 2.5 (C)</p> Signup and view all the answers

<p>Voltage source inverter (C)</p> Signup and view all the answers

<p>About 20% (D)</p> Signup and view all the answers

<p>They allow regeneration and unity power factor operation. (A)</p> Signup and view all the answers

<p>Improves operational efficiency. (B)</p> Signup and view all the answers

<p>The emergence of GTOs and microprocessor-based control systems. (C)</p> Signup and view all the answers

<p>Dependent on terminal voltage and slip frequency. (D)</p> Signup and view all the answers

<p>It improves. (B)</p> Signup and view all the answers

<p>It can occur when starting on fixed frequency supply. (A)</p> Signup and view all the answers

<p>Illustrates different torque values at varying supply frequencies. (D)</p> Signup and view all the answers

<p>The motor experiences low starting torque due to low power factor. (C)</p> Signup and view all the answers

<p>Allows for high-speed processing operations (C)</p> Signup and view all the answers

<p>Storing energy and supplying reactive power (D)</p> Signup and view all the answers

<p>4-quadrant pulse width modulated converter (D)</p> Signup and view all the answers

<p>Increased physical size of the control unit (B)</p> Signup and view all the answers

<p>Variable voltage up to 2180 V and variable frequency up to 160 Hz (A)</p> Signup and view all the answers

<p>It provides reactive power needed by the induction motor (D)</p> Signup and view all the answers

<p>To absorb second order harmonics from the current (B)</p> Signup and view all the answers

<p>Comprehensive diagnostics for all electronic devices (D)</p> Signup and view all the answers

<p>To obtain unity power factor and eliminate separate power factor correction (C)</p> Signup and view all the answers

<p>Complexity and size of conventional control equipment (A)</p> Signup and view all the answers

<p>Insensitivity to environmental conditions (D)</p> Signup and view all the answers

<p>Increased hauling capacity and better efficiency (B)</p> Signup and view all the answers

<p>Problems with brush gear and commutator (D)</p> Signup and view all the answers

<p>High harmonic injection into the power supply (D)</p> Signup and view all the answers

<p>Thyristor-based control systems (C)</p> Signup and view all the answers

<p>Reduction of energy bills and energy conservation (D)</p> Signup and view all the answers

<p>Simplicity of design and absence of wear components (A)</p> Signup and view all the answers

<p>It allows the input current to maintain phase alignment with the source voltage. (C)</p> Signup and view all the answers

<p>To store diagnostic messages for external retrieval. (C)</p> Signup and view all the answers

<p>Level I (C)</p> Signup and view all the answers

<p>80186/16-bit microprocessor programmed similar to main processing units. (B)</p> Signup and view all the answers

<p>It is in quadrature with the voltage across the reactor. (D)</p> Signup and view all the answers

<p>There are no limitations imposed due to bar-to-bar voltage. (B)</p> Signup and view all the answers

<p>They can achieve higher power distribution without increasing weight. (D)</p> Signup and view all the answers

<p>It allows efficient energy conversion in regenerative braking. (A)</p> Signup and view all the answers

<p>Microprocessor-based logic for reduced mechanical components. (B)</p> Signup and view all the answers

<p>Induction motors exhibit a markedly steeper torque-speed curve. (C)</p> Signup and view all the answers

<p>It guides the crew on fault locations and suggests remedies. (A)</p> Signup and view all the answers

<p>It allows for flexibility in adapting to local operational needs. (C)</p> Signup and view all the answers

<p>It decreases. (D)</p> Signup and view all the answers

<p>Cables can be lighter, reducing overall system weight. (A)</p> Signup and view all the answers

<p>The software can adapt to various operational needs dynamically. (A)</p> Signup and view all the answers

<p>Current source inverter (B)</p> Signup and view all the answers

<p>Vacuum braking (B)</p> Signup and view all the answers

<p>To match the motor specifications (C)</p> Signup and view all the answers

<p>They are about 20% more energy efficient. (A)</p> Signup and view all the answers

<p>Expected vehicle speed (C)</p> Signup and view all the answers

<p>It enables electric braking down to standstill. (D)</p> Signup and view all the answers

<p>To reduce ripple in rectified DC (C)</p> Signup and view all the answers

<p>The availability of GTOs and microprocessor-based control systems. (B)</p> Signup and view all the answers

<p>Large torque is required below rated speed. (C)</p> Signup and view all the answers

<p>DC supply for the load side converter (A)</p> Signup and view all the answers

<p>The rotor must be mechanically driven at super synchronous speeds. (C)</p> Signup and view all the answers

<p>It improves rotor power factor, increasing starting torque. (C)</p> Signup and view all the answers

<p>Stable air gap flux (C)</p> Signup and view all the answers

<p>The starting current is 5 to 6 times the rated current, but torque is low. (C)</p> Signup and view all the answers

<p>It can lead to low frequency crawling conditions. (A)</p> Signup and view all the answers

<p>It depends on the supply voltage and frequency. (D)</p> Signup and view all the answers

<p>A low power factor limits the available starting torque. (B)</p> Signup and view all the answers

Modern rail vehicles use three-phase AC drive technology with GTO thyristors and microprocessor control.

DC motors have issues with brushes, commutators and a lower power-to-weight ratio compared to three-phase AC motors.

A microprocessor system controls the vehicle, monitors components, performs diagnostics and selects the best PWM technique for motor performance.

Regeneration is used to reduce energy bills and save energy for national needs, by reclaiming power during braking.

Three-phase motors are robust, low maintenance, and insensitive to dust, vibrations , and heat compared DC motors.

Increasing need for locomotives to carry higher loads and make maximum use of track adhesion (friction)

Locomotives designed to reduce track maintenance efforts needed, with robust construction.

Three-phase drives offer energy efficiency through regeneration and unity power factor operation, enabling improved starting, braking, and acceleration.

Induction motors are approximately 20% less energy efficient than DC drives.

A drive system that controls both the voltage and frequency supplied to the motor, enabling variable speed control.

A typical cage rotor induction motor's starting current is 5 to 6 times its rated current.

Starting torque of a typical cage rotor induction motor is low due to low power factor.

Regeneration occurs only when the rotor is driven mechanically at super-synchronous speeds.

This drive varies the frequency to improve starting torque and avoid low-frequency crawling.

Graph that depicts the torque and speed of an induction motor at different supply frequencies (constant air gap flux).

The maximum torque a motor can produce at a particular speed, beyond which it can't accelerate further.

A method to keep breakdown torque steady as motor speed changes. Keeps voltage and frequency in a consistent ratio.

Motors have a maximum voltage they can safely handle.

Magnetic field between the motor's rotor and stator. Impacts torque & motor capability.

Systems where high torque is needed at low speeds, but less torque at high speeds.

How motor voltage and current change with speed, crucial for optimal operation in traction drives.

A type of inverter used to control the current waveform provided to the motor.

Inverter controling the voltage waveform provided to the motor. Requires sophisticated control.

Increases the output voltage of the front-end converter.

Reduces high voltage AC to a usable level for the motor.

Microprocessors enable high-speed processing for control, accurate operation, and self-diagnostics, simplifying complex systems.

Microprocessors manage driving, braking, speed regulation, component monitoring, automatic changeover, and diagnostics.

A VS Inverter generates variable voltage (0-2180V) and frequency (0-160Hz) to power the motor.

A DC link acts as an energy reservoir, supplying power to the motor and smoothing out fluctuations.

The DC link includes a capacitor, tuned filter, and over-voltage protection, managing energy flow and filtering harmonics.

A four-quadrant converter converts AC to DC, achieving near perfect power factor correction.

The input converter achieves near unity power factor, eliminating the need for separate power factor correction equipment.

ABB locomotives use a VS Inverter, DC link, and a four-quadrant input converter for efficient and controlled power delivery.

The series tuned filter in the DC link absorbs second order harmonics generated by the four-quadrant converter.

The current flowing into the converter, which is in quadrature (perpendicular) to the voltage across the reactor (EL).

A condition where the converter input current (IS) is in phase with the source voltage (ES), maximizing power transfer efficiency.

The signal used to control the pulse width modulation (PWM) of the DC link voltage, directly influencing the fundamental component of the converter input voltage.

The diagnostic system classifies fault levels into three categories: Level I (audio-visual indication), Level II (audio-visual and bogie isolation), and Level III (automatic corrective action).

Faults in this category trigger only audio-visual alerts and recording. The diagnostic system automatically takes corrective action to maintain normal operation.

Three-phase AC motors are more efficient and robust than DC motors, offering advantages in terms of maintenance, reliability, and track friendliness.

DC traction motors have limitations: brush and commutator wear, lower power-to-weight ratio, and inefficiency due to high harmonic injection.

Regeneration in traction systems captures energy during braking and feeds it back into the power system, saving energy and reducing costs.

VVVF drive controls both voltage and frequency applied to the motor, providing precise speed control and improved performance.

Microprocessors enable precise control, self-diagnostics, improved performance, and optimized energy efficiency in traction systems.

Three-phase traction systems typically include a DC link, input-side converter, and a voltage source inverter (VS Inverter).

Three-phase AC traction motors offer significant advantages over DC motors, including higher speed, improved efficiency, and reduced maintenance.

The torque-speed characteristic of an induction motor is steeper than that of DC motors, allowing for better use of traction effort and higher adhesion.

Regenerative braking uses electric braking to recover energy during deceleration, improving efficiency and reducing energy consumption.

Microprocessors improve reliability, efficiency, and safety by enabling self-diagnostics, flexible control, and optimized energy use.

A three-phase traction system typically includes a DC link, an input converter, and a voltage source inverter (VS Inverter) for powering the motor.

The input converter rectifies AC power from the grid into DC power, achieving near unity power factor for better energy efficiency.

The VS Inverter generates variable voltage and frequency to control the motor speed and torque, providing precise speed control and optimized performance.

A type of inverter that controls the current waveform supplied to the motor. Older technology.

A type of inverter that controls the voltage supplied to the motor. Modern technology.

Three-phase induction motor drives are around 20% more energy-efficient than DC drives.

Three-phase drives can regenerate power, meaning they capture braking energy and return it to the system, improving energy efficiency.

Three-phase drives can operate at unity power factor, meaning they use power more efficiently with almost no losses.

Induction motors have a speed-torque characteristic that determines their performance. The relationship between speed and torque is affected by voltage and frequency.

Induction motors have low starting torque due to their low power factor, requiring a variable frequency drive for smoother acceleration.

VFDs control the frequency and voltage supplied to the motor, allowing for controlled acceleration and improved starting performance.

Variable Voltage Variable Frequency (VVVF) drives control both the voltage and frequency supplied to the motor, allowing for precise speed control and energy efficiency.

Microprocessors provide precise control, self-diagnostics, improved performance, and optimized energy efficiency in traction systems.

The diagnostic system classifies fault levels into three categories: Level I (audio-visual indication), Level II (audio-visual and bogie isolation), and Level III (automatic corrective action).