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.
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.
Which 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 motor control?
A speed control system of traction motors for electric vehicles comprises a traction motor for causing an electric vehicle to run, a D.C. supply source for supplying voltage to the traction motor, a chopper for chopping the voltage fed from the D.C. supply source to the motor, and a chopper control circuit for …
Are locomotives AC or DC?
All in all, the AC traction locomotive offers about twice the amount of adhesion as a DC unit. Therefore, a modern lightweight AC locomotive such as the RX500 can provide as much or more tractive effort than an old style DC unit like the SW1200 which weighs 60% more.
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. The cost of the conductor gets less.
Which motor is used in metro train?
THREE PHASE SLIP RING INDUCTION MOTOR has been used in DELHI METRO. Dc series motor is ideal for traction but the maintenance cost of which is very high also needs the conversion and smoothening of AC voltages.IM has less maintenance,high starting torque, cheap etc.
Why DC is used in trains?
Direct current, either directly supplied, or converted from AC onboard a train, is the most commonly used. … The equipment in the DC traction system is less costly, lighter, and more efficient than an AC traction system. It also causes no electrical interference with nearby communication lines.”
Which method is best for series traction motor?
Explanation: Series-parallel control method is superior to the rheostatic control insofar as efficiency is concerned. However, it is limited to two speed steps. The method is commonly employed for speed control of series traction motors.
Which motor is used in lift and escalator?
AC slip ring or DC compound motors are prefer for lifts. Shunt type commutator motors are preferred in case of single phase installation. The latest lift designs use 3-phase induction motors with variable frequency drive electronic controls.
What is the need for traction motor control?
The control of traction motors for starting and for smooth acceleration is very much essential to avoid damage to the motors. The control equipment is provided for manual and automatic operation. Usually a master controller is used for the purpose.
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.
How much does a locomotive traction motor weight?
If we just isolate the situation to the weight of the bogies themselves, the bogies on the 6000 class weigh 21.2 tonnes and those on the 5000 class weigh 28.5 tonnes.
Why train engines are not turned off?
Another reason for not turning off diesel train engines, lies in the engine itself. … It is also interesting to know that while diesel locomotives are idling, fuel consumption is more than when the train is moving. This is because, while idling, the batteries are being charged, and the air compression is in operation.
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.
Are diesel locomotives AC or DC?
In a diesel–electric locomotive, the diesel engine drives either an electrical DC generator (generally, less than 3,000 horsepower (2,200 kW) net for traction), or an electrical AC alternator-rectifier (generally 3,000 horsepower (2,200 kW) net or more for traction), the output of which provides power to the traction …