Which motor is best for traction?
Many single phase ac motors have been developed for traction purposes but only compensated series type commutator motor is found to be best suited for traction. Single phase induction motors have been abandoned as they are not capable of developing high starting torque.
What are the methods of speed control of traction motor?
Speed-time curve mainly consists of
- Initial acceleration. (a) Constant acceleration or acceleration while notching up and. (b)Speed curve running or acceleration on the speed curve.
- Constant speed run or free run.
- Coasting and.
- Retardation or braking.
Why a series motor is preferred for the electric traction?
DC Series motor has high rate of acceleration and retardation. DC Series motor is variable speed motor. Due to these characteristics motor is protected against overload. … DC series motor has develops high torque at low speeds, low torque at high speed, this is the basic requirement of traction unit.
Why is it called a traction motor?
Before the mid-20th century, a single large motor was often used to drive multiple wheels through connecting rods. This was the same way that steam locomotives would turn their drive wheels. … This is called a “nose-suspended traction motor”.
Why is traction used?
Most often, traction uses devices such as weights and pulleys to put tension on a displaced bone or joint, such as a dislocated shoulder. The tension helps put the joint back in position and keep it still. Traction is also used to keep a group of muscles (such as the neck muscles) stretched to reduce muscle spasms.
Which of the following is not the method of speed control of traction motors?
Which of the following is not the method of speed control in DC series motor? Explanation: Diverter means adding a variable resistance in parallel with field winding. Tapped field control is the method where field ampere turns are adjusted in steps by varying the number of turns included in the circuit.
Which motor is used in tramway?
This paper compares five different motor types used in variable speed drives: a dc motor with a mechanical commutator and with electromagnetic or permanent magnets excitation, a cage induction motor, asynchronous cascade with a slip‐ring motor and a brushless motor with PM excitation.
What are the special features of traction motor?
The ideal characteristics of an electric motor drive for traction application in an electric and hybrid electric vehicle are high torque at low speed region for fast acceleration, hill climbing and obstacle negotiation, and low torque at high speed for normal driving.
Which locomotive has highest operational availability?
Answer: Electric Locomotive:- An electric locomotive requires much less time for maintenance and repairs than a steam locomotive and such vehicles can, if desired, be kept in service for 95% or more. Diesel Locomotive:- It is available for hauling for about 90% of its working days.
Why induction motors are not suitable for electric traction?
Electrical Engineering (EE) Question
Three phase induction motor is not suitable for traction purposes because traction motor requires high starting torque, for urban and sub urban lines, the acceleration (speed at starting) should be high and simple speed control is required to start and stop the motor easily.
What happens when two DC motors are connected in parallel?
The two motors are required to run at the same speed, so wiring them in parallel will ensure same PWM signal to both these motors. Both the motors are unidirectional. Both the motors are identical (electrical rating, manufacturer, load).
Which DC motor has maximum self loading property?
Which DC motor has got maximum self-loading property? Explanation: A differentially compound DC motor, flux reduces so sharply at small increase in load at higher values of load.
Which is a method of starting and speed control of DC traction motors?
Starting resistance is inserted in series with the motors connected in series or series-parallel control at the start and then gradually reduced to zero with the increase in speed of motors.