In this article we will discuss about the drawbacks of diesel electric traction systems. Drawbacks of Tramways: The power is supplied to the tramcar, usually at 600 dc volts, from a single overhead conductor (of positive polarity) fed at suitable points from a central power station or substations, the track rail forms the return conductor. The tramcar is provided with [...]
Systems of track electrification comprises: 1. DC System 2. Single Phase AC System 3. Three Phase AC System 4. Composite Systems. 1. DC System: In this system the electric motors employed for getting the necessary motive power are usually dc series motors, although the compound motors are coming into favour for tramways and trolley buses where regenerative braking is desired. [...]
The various traction systems commonly used are described as follows: 1. Direct Steam Engine Drive 2. Direct Internal Combustion Engine Drive 3. Steam Electric Drive 4. Internal Combustion Engine Electric Drive 5. Petrol Electric Traction 6. Battery Electric Drive 7. Electric Drive. System # 1. Direct Steam Engine Drive: The steam engine drive used to be widely employed for railway [...]
In this article we will discuss about:- 1. Introduction to Train Movement and Energy Consumption 2. Typical Speed-Time Curves 3. Crest Speed, Average Speed and Schedule Speed of Train 4. Simplified Speed-Time Curves of Train 5. Mechanics of Train Movement 6. Tractive Effort for Propulsion of Train 7. Power Output from the Driving Axles 8. Energy Output from Driving Axles [...]
For trams, trolley buses and for railways operating at 1,500 V and above overhead contact wire is used. The design of overhead system is more complex in comparison to conductor rail system because of greater difficulty of ensuring that the collector and contact wire remain in contact at a fairly even pressure. Tramways and Trolley Buses: The overhead construction for [...]
In this article we will discuss about the history and current collection systems of electric traction. History of Electric Traction: Electric traction was first introduced in Britain in the year 1890 at 600 V dc using third rail for urban and suburban services. For its application to long distance main-line service the developments were towards increasing the operating voltage and [...]
Electric power is taken from grid supply at 220/132 kV and then stepped down to 25 kV single phase at traction substations through step-down transformers and suitable switchgear. The electric power at 25 kV ac is transmitted to feeding posts through feeders. Feeding posts are located opposite the track. At feeding posts, this power is fed to OHE above track [...]
The substations are necessary for control of electric supply to a considerably long network for electric traction. DC Substations: These substations are required for tramways, trolley buses and railways. Their functions are to: (i) Step down the transmission voltage to the utilization level (ii) Convert it into dc and (iii) Sectionalizing the overhead equipment. Such substations, therefore, consist of step-down [...]
Simplest type of overhead equipment consists of a single contact wire supported either by bracket or by overhead span. The maximum distance between two consecutive supports with such a system is restricted to 30 m and speed is limited to 30 kmph. The single contact wire system, therefore, finds application for tramcars or in complicated yards and terminal stations where [...]
The current in the overhead system is collected with the help of sliding contact collector mounted on the roof of the vehicle. The main requirement of a current collector is that it should, under no circumstances, leave the contact of overhead equipment. Contact wire in all practical installations is never perfectly horizontal, it rises and falls depending upon the weight [...]