Why Are DC Motors Used in Trains Not AC Motors?

DC (Direct Current) motors have traditionally been recommended for use in trains for a wide range of reasons, however it is important to remember that there is an increasing preference toward the usage of AC (Alternating Current) motors in current train systems.

Why do trains utilize DC motors?

DC motors are employed in trains due to their high torque & excellent speed control. DC motors, as opposed to AC motors, may provide industry applications with an appropriate balance of high starting torque and adjustable speed, resulting in seamless yet precise performance. Trains are large-scale applications; thus, a DC motor can effectively & safely carry the heavy load ahead.

DC motors are additionally a great option for train windshield wipers, a difficult application that needs to be capable of operating in a wide range of conditions. A decent windscreen wiper motor must function properly at any speed, regardless of the weather. This requires accurate speed control, allowing them to respond smoothly & easily to changing conditions.

What are the advantages of DC motors?

DC motors have numerous advantages, making them an ideal alternative to be utilized on trains around the world.

1). Excellent speed control

2). Smooth operation

3). High Torque

4). Control & Traction Characteristics

5). Ease of Reversing

6). Regenerative Braking

7). Simplicity and maintenance:

1). Excellent speed control

DC motors are noted for their excellent speed control, providing the precision & safety that trains demand. Changing the armature (or) field voltage allows for a wide range of speed variations.

2). Smooth operation

DC motors can offer the requisite speed and power in a variety of applications, including trains. Trains, as an essential mode of transportation, should be able to start & stop quickly in order to save time and in the event of an emergency.

3). High Torque

DC motors have considerable high torque, making them ideal for big loads like trains. This implies that the motor can deliver an uninterrupted supply of power over extended periods of time, which is perfect for trains that run for more than 12 hours a day.

4). Control & Traction Characteristics

DC motors offers good control qualities, particularly at low speeds. This is essential for the trains during the acceleration, deceleration, & starting from a stopped position. DC motors provide smooth speed control in these kinds of applications.

5). Ease of Reversing

DC motors have the natural ability to easily reverse direction by changing the polarity of applied voltage. This feature is useful in train operations, allowing for simple and efficient control of both forward & reverse movements.

6). Regenerative Braking

DC motors can conduct regenerative braking, which converts kinetic energy back into electrical energy as the train slows down. This energy can be returned to the power system (or) utilized further in the train system.

7). Simplicity and Maintenance

DC motors are comparatively simple to construct & require less maintenance than some AC motor systems. DC traction motors used to be popular in trains due to their simplicity.

AC vs DC-what’s the difference? - Locomotives

However, with technological breakthroughs & the advancement of power electronics, AC traction motors are now increasingly widespread in modern train systems. AC motors have several advantages, including enhanced efficiency, lower maintenance requirements, & better performance at higher speeds. Furthermore, advances in control systems, including variable frequency drives, have improved the capacity to successfully control alternating current motors.

In conclusion, while DC motors have traditionally been used in trains because of their control characteristics & simplicity, the railway industry is now gradually moving to using AC motors in many modern train systems due to their improved efficiency and performance characteristics, particularly at higher speeds.