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. Motors for a typical locomotive would be in the range 400 to 600 kW.
Which motor is used in electric traction?
What kind of motor is used in trains?
Series-wound DC motors. That means current flows through the armature, then through the fields. They have high starting torque, favorable for starting a train. Nowadays the trend is toward AC motors, typically a 3-phase induction motordriven by a DC->AC inverter control.
Why induction motor is used in traction?
This is the most important feature of traction motor provides opportunity for saving on energy but also smoothness in braking, saving on wear and tear in mechanical braking system. An Induction motor works as a generator if mechanical speed is more than the synchronous speed.12 мая 2013 г.
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.
Why is 25kV used in electric traction?
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. The cost of the conductor gets less.
Which motor is used in tramway?
Mostly DC series motors are used in this system. For trolley buses and tramways, DC compound motors are used where regenerative braking is required. The various operating voltages of DC traction system include 600V, 750 V, 1500V and 3000V.
Which current is used in railway?
Why do trains have two pantographs?
Firstly, two pantographs are fixed as to use the other one when the running panto is damaged. Both of them don’t commission at a time. 2. Usually, Rear panto is preferred over front panto as pulling is more easier than pushing.
Which type of DC motor is used for traction?
Traditionally, these were series-wound brushed DC motors, usually running on approximately 600 volts. The availability of high-powered semiconductors (thyristors and the IGBT) has now made practical the use of much simpler, higher-reliability AC induction motors known as asynchronous traction motors.
What is traction inverter?
Traction inverters convert dc power from an on-board high voltage (HV) battery into ac power to drive the main motor or motors of an electric vehicle. In addition, traction inverters perform functions such as voltage boosting, switch protection and regenerative braking.
Which type of induction motor is best for pole changing method?
This method of controlling the speed by pole changing is used mainly for cage motor only because the cage rotor automatically develops a number of poles, which is equal to the poles of the stator winding. The number of stator poles can be changed by the following three methods.
What is more efficient AC or DC?
1. DC power is significantly more energy efficient than AC power. DC motors and appliances have higher efficiency and power to size characteristics. … The greater efficiency resulting from recent developments in DC converter technology allows improvements in electricity delivery over long distances.
Which is more dangerous AC or DC and why?
A.C. is said to be four to five times more dangerous than D.C. For one thing, A.C. causes more severe muscular contractions. … The frequency of the AC has a lot to do with the effect on the human body. Unfortunately, 60 cycles is in the most harmful range. At this frequency, as little as 25 volts can kill.
What are the disadvantages of electric traction?
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.