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Traction Control of Electric Locomotives PowerPoint Presentation
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Traction Control of Electric Locomotives

Traction Control of Electric Locomotives

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Traction Control of Electric Locomotives

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    1. Traction Control of Electric Locomotives

    2. INTRODUCTION Driving forward of vehicle is called Traction and the system, which employs this type of mechanism is called Traction system classified broadly into two groups namely: (1)non-Electric traction systems (2)Electric traction systems

    3. Requirements of an Ideal Traction System High starting pulling effort in order to have rapid acceleration. Equipment capable of withstanding large temporary overloads for short periods. The locomotive should be self contained and able to run on any route. Capability of withstanding voltage fluctuations and temporary interruption of supply. Parallel running usually more than one motor (two or four motors ) should be possible.

    4. ADVANTAGE OF ELECTRIC TRACTION . Cheapness. It is cheapest method of all other methods of traction. Cleanliness. It is free from smoke and flue gasses Maintenance cost. Maintenance and repair cost is about 50% of steam traction system. Starting time. It can be started without loss of time. High starting torque. This system uses of d.c. and a.c. series motors which has a very high starting torque. Braking. In electric traction , regenerative breaking is used which feeds back 40%of the energy. Saving in high grade coal. No coal is required for electric traction.

    5. DISADVANTAGE OF ELECTRIC TRACTION Higher initial expenditure. Failure of supply is a problem. Additional equipments are required for breaking purposes. The electrically operated vehicles have to move only on electrified track. Interference with telegraphs and telephone lines.

    6. COMPONENTS OF AN A.C LOCOMOTIVE CATENARY - This is the overhead wire of special cross-section. PANTOGRAPH - This is a device used for collecting current from the catenary i.e. the over head lines. CIRCUIT BREAKERS - The function of circuit breaker is to disconnect the engine from the line side in case of some fault ON LOAD TAP CHANGER - On load tap changer is used for varying the output voltage for controlling the speed of motor TRANSFORMER - A tap changing transformer is installed in the locomotive for stepping down the voltage according to the requirement of traction motors RECTIFIERS - Semiconductor rectifiers are used for conversion of A.C power into D.C power SMOOTHING REACTORS - Any ripples found on the output side of the rectifier are eliminated by the smoothing reactor fitted after the rectifier.

    7. SEPEX

    8. THYRISTOR CONTROL

    9. DC Choppers

    10. AC TRACTION MOTOR

    11. AC Locomotives with DC Drives

    12. DC TRACTION MOTOR

    13. The DC Traction Motor: How it Drives the Axle

    14. DC Resistance Control

    15. DC Power Circuit

    16. Field Weakening

    17. Braking in traction motors Dynamic Braking: where the motors become generators and feed the resulting current back. It classified into two categories: 1 Plugging 2. Rheostatic Braking 3. Regenerative Braking PLUGGING: Generally plugging is applied by changing the phase sequence of the three phase induction and synchronous motor

    18. Rheostatic Braking The motors become generators and feed the resulting current into an on-board resistance. When the driver calls for brake, the power circuit connections to the motors are changed from their power configuration to a brake configuration and the resistors inserted into the motor circuit. As the motor generated energy is dispersed in the resistors and the train speed slows, the resistors are switched out in steps, just as they are during acceleration.

    19. Regenerative Braking the motors become generators and feed the resulting current back into the supply system a train could use its motors to act as generators and that this would provide some braking effect if a suitable way could be found to dispose of the energy. Trains were designed therefore, which could return current, generated during braking, to the supply system for use by other trains.

    20. CONCLUSION no single motor is ideal for traction purposes. But; DC Series Motors are most suitable for this work Power Electronics have been resorted to in a major way as in case of thyristor control. Different types of braking for the traction system was studied.