Magnetic pressure is used to counteract the effects of the gravitational and any other accelerations. Recent trends in electric traction: Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields.
What is modern electric traction?
The system which use electrical power for traction system i.e. for railways, trams, trolleys, etc. is called electrical traction. … The three main types of electric traction systems that exist are as follows: Direct Current (DC) electrification system. Alternating Current (AC) electrification system. Composite system.
What are the features of electric traction?
FEATURE OF TRACTION MOTOR DRIVE Electrical Features High Starting Torque Simple Speed Control Regenerative Braking Better Commutation Capability Of Withstanding Voltage Fluctuations. Mechanical Features Light In Weight. Small Space Requirement. Robust And Should Be Able To Withstand Vibration.
What is traction return current?
above traction return current flowing in the single traction return rails creates a longitudinal AC voltage along its length, which is a function of the current value and the impedance of the traction return rail.
What is electric traction list its advantages?
The electric traction system is the most efficient of all other traction system such as steam and internal combustion (IC) engine type systems. It offers several benefits over other systems, including quick start and stop, very efficient, pollution-free, easy to handle and easy speed control.
Why DC is used in trains?
DC motors are used on trains is because of their high torque and good speed control. Compared to AC motors, DC motors can provide industry applications with a fine balance of strong starting torque and controllable speed for seamless yet precise performance.
Which motor is used in electric traction?
AC traction motors have replaced DC motors in many traction applications. The motors used are induction or asynchronous motors designed to have characteristics suitable for traction. The speed and torque of the motor are controlled by varying the frequency, voltage and current applied to the stator coils.
What is meant by electric traction?
Introduction: By electric traction is meant locomotion in which the driving (or tractive) force is obtained from electric motors. It is used in electric trains, tramcars, trolley buses and diesel-electric vehicles etc.
Which motor is used in tramway?
Dc motor (Ma) and induction motor (Mc) are currently manufactured and used in 105 N tram drive, their parameters are available. Dc motor (Mb), brushless motor (Me) and slip-ring motor (Md) pa- rameters have been determined by analysis.
What are the requirements of ideal traction system?
The requirements of ideal traction systems:
- Ideal traction system should have capability of developing high tractive effort in order to have rapid acceleration.
- The speed control of the traction motors should be easy.
- Vehicles should be able to run on any route, without interruption.
Do trains run on AC or DC?
Direct current, either directly supplied, or converted from AC onboard a train, is the most commonly used. This is because, according to railsystem.net, “DC consumes less energy compared to an AC unit for operating the same service conditions.
What is traction voltage?
Standardized traction voltages are 750 V DC, 1500 V DC and 3000 V DC. The three-phase voltage from the local utility is stepped down and rectified in the traction substations to provide the required DC voltage. … Electrical, mechanical and civil design of the substations. Medium-voltage switchgear. Rectifier transformers.
Why 25kV is used in railway traction system?
The main reason for 25kV voltage used in railway is, that 25 kV AC more economical than 1.5kV DC voltage system. … Since 25kV voltage system has higher voltage, the higher voltage reduces the current flow through conductor; this reflects to reduce the conductor size.
What is the major drawback of electric traction?
6. Disadvantages of Electric Traction (i) High initial expenditure (ii) Failure of supply is a problem (iii) Electrically operated vehicles have to move only on electrified track (iv) For braking & control, additional equipments required (v) Interference with telegraphs and telephone lines.
What are the disadvantages of electric traction *?
Disadvantages: Electrically operated vehicles have to move on guided track only. Problem of supply failure. The leakage of current from the distribution mains and drop of volts in the track are to be kept within the prescribed limits.
What are four advantages of traction drives?
Negligible Transmission Error
- Smooth rolling contact allows for negligible transmission error.
- Eliminates speed irregularity inherent in gear transmissions.
- Great fit in application where the angular velocity ratio is important.