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.
Are train motors AC or DC?
A modern railway 3-phase traction motor is controlled by feeding in three AC currents which interact to cause the machine to turn. The three phases are most easily provided by an inverter which supplies the three variable voltage, variable frequency (VVVF) motor inputs.
Which type of DC motor is used in Indian electric railways?
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.
Do electric trains have engines?
Instead of a tank of diesel and an engine, the train has a tank of hydrogen and a fuel cell that combines the hydrogen with oxygen from the air, without combustion. With the only emission being water, the fuel cells provide power and have zero emissions.
Are locomotives AC or DC?
Depending on the design of the train, it can either produce AC or DC current using a generator powered by the diesel engine. Because of various electrical connections, multiple locomotives can be operated by a single lead until operated by a single crew.
Which is more preferable AC or DC?
Answer: Ac is more preferred than dc because it is easy to maintain and change the voltage of ac for transmission and distribution purpose. Plant cost of ac transmission is much lower compared to dc transimission.
Which current is used in electric train?
Railway electrification systems using alternating current (AC) at 25 kilovolts (kV) are used worldwide, especially for high-speed rail.
Which motor is used in train fan?
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.
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 in a DC motor?
A DC motor consists of an stator, an armature, a rotor and a commutator with brushes. Opposite polarity between the two magnetic fields inside the motor cause it to turn. DC motors are the simplest type of motor and are used in household appliances, such as electric razors, and in electric windows in cars.
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.
Are electric trains faster than diesel?
Each type of locomotive has benefits and drawbacks, when considering the cost, environmental impact, visual impact and performance. … While more costly, the electric locomotives are faster, mainly because they accelerate faster than diesel trains and have higher maximum speeds.
Why do train wheels not slip?
The heavy weight of wagons can be treated as a huge force. This force creates a frictional force between wheels and railway. So wheels don’t slip on railway tracks when pulled by a locomotive. … As per Amonton’s first law of friction, “The force of friction is directly proportional to the applied load”.
Which is dangerous current AC or DC?
Alternating current (A.C) is five times more dangerous than Direct current (D.C). The frequency of the alternating current is the main reason for this severe effect on the human body. The frequency of 60 cycles is in an extremely harmful range. At this frequency, even a small voltage of 25 volts can kill a person.
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 …
Why is AC preferred over DC?
AC voltage is preferred over DC voltage because it is economical and less complicated. AC voltage is more efficient than DC since minimum energy loss happens during transmission.