the driver of a train hauled by 3 phase Locomotive wants to stop or slow down a train, he applies regenerative braking. The motors of the locomotives which are normally pulling the train, change their mode of operation from motor to a generator. The mechanical energy of the train is converted to electrical energy by the generator, which then goes to the power supply grid.(Power Supply grid here means the Overhead Wire). This feature is called regenerative braking. Thus, even braking losses are gainfully utilised in three phase locomotives.
In other words, This is an electrical braking system in which brakes are applied on loco without physical application or brake block failure.
Advantages of Regenerative Braking:
1. Brake block does not apply on wheel so wheel and brake block wear is
eliminated.
2. Reliable braking.
3. Smooth controlling.
4. Energy generated during braking is fed back to OHE i.e. it works just
like a small power station and helps in energy conservation.
5. Braking is available up to 0 KMPH.
Effort of NCR to save energy through Regenerative Braking:
Application of brakes in trains invariably results in loss of energy. However, conservation of energy by utilising the technology of regenerative braking in electric locomotives has helped the North Central Railway to save about 15 million units of electricity costing about Rs six crore in the current financial year.When trains are required to be stopped or slowed down near railway stations or signals, the driver applies brakes. For this purpose, there are mechanical brakes, which work on compressed air, by converting the energy of the motion of a running train to frictional losses.
Pointedly, over the years, the technology upgradation has taken place in electric locomotives, which has contributed in overall objective of Railways to conserve precious electric energy. With this objective in mind, 3 phase locomotives(WAP 5,WAP 7 & WAG 9) were inducted into Railways almost 15 years ago. Initially, these locomotives were imported from Switzerland on ToT basis (Transfer of Technology). As per this agreement, when complete equipment is imported, the foreign company also undertakes to transfer the entire knowhow to the indigenous company for enabling the latter to manufacture the imported equipment in the country. After 5 years, CLW (Chitranjan Locomotives Works) started the production of three phase locomotive indigenously gradually reducing the import content to 5% only.
North Central Railway runs around 250 passenger trains and 150 trains every day by electric locomotives. Out of these, about 25% of trains are run by about three phase locomotives. Since drivers running such locomotives were required to be given special training to utilise this feature, NCR has trained all its drivers to utilise regenerative braking. Due to intelligent application of this feature, NCR has saved about 15 million units of electricity costing Rs 6 crores.
Source of this info:
click hereCourtesy: Ashraf Jamal
Source of the "Advantages of Regenerative Braking: Point 6.9.8 in page 36 of the 103 page PDF Document which is already attached with Re# 1400167-40 in /blog/post/1400167 by me.
Inference drawn from above discussion:
3 Phase Locomotive does not need any power from Overhead wire at the time of applying brake to stop or slow down the Locomotive.
So from the above discussion it is also found that "3 Phase Locomotives" also saves Energy and Money of Indian Railways to a great extent through this technology of "Regenerative Braking" which is not present neither in any other Locomotive nor in any EMU DEMU or MEMU trains of Indian Railways.
So, in future in the World of Electric Locomotive Railway should rely on 3 names WAP-5 WAP-7 and WAG -9 for this very important advantage of these 3 Locomotive classes.
Attached Image:
Goods train being helped by a WAP7 from the rear
Pic Courtesy: prdp
Image Link:
click hereThis Pic is taken from a Video of by prdp the link of which is:
click hereVideo Courtesy: prdp
TKD WAP-7 30347
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