DEVELOPMENT HISTORY OF POWER GENERATION IN "LHB" AC/NAC

POWER GENERATION IN MIX AC/NAC LHB

The "conventional" LHB uses EOG ( End On Generation ) . That is the rakes of the LHB are powered by Generator Cars, These are Diesel generators capable of producing 750KW at 750V 50Hz.
 There are two of these cars for Each train, both of which are positioned at the both (extreme) ends of the LHB rake. According to the Power Load these cars provide electricity to coaches for RMPU, lighting & other essentials.
But soon arises the need of running NAC LHB or A mix of AC/NAC LHB coaches, for which the existing Power cars were of over capacity. therefore,
So as to meet the satisfaction of the passengers, Higher capacity, the need for design and subsequent Running a mix of AC and NAC LHB Coaches  was felt. RCF has effectively begun fabricating Non-AC LHB and 276 such Coaches have gone into service till 31st March 2014 and dealing with Northern Railway, North Western Railway, Western Railway, East Central Railway and Eastern Railway.

LHB NAC (right) & AC (left) Coaches

With an initiative Duronto Rakes with a mix of LHB AC and NON-AC were first rolled out from Rail Coach Factory, kapurthala. 

The approx. Electric Load of the train is about 250KW for which the Existing EOG Power Cars were over Capacity.

  

Though these rakes are Supplied with EOG (End On Generation), innovations were made to make LHB Fiat bogies S.G (Self Generating) 

Following Were some arrangements Earlier developed/used by Indian railways at RCF Kapurthala.

CARDAN SHAFT ARRANGEMENT

In this course of action, 25KW alternator was of traditional except from belt transmission supplanted with a cardan shaft which was driven by a gear box mounted on the axle. The alternator was mounted on the coach underframe to deal with space requirements in the bogie. This design was given by LHB to RCF.

The same was then put into service between JAT & NDLS for the trail. But sooner in a short period of service the flaws of the arrangement were shown out. The flaws was non-damping of vibrations rising up out of the track abnormalities coming about failure because of breakage of gear box & Cardan shaft, faliure of clasp given to coupling of Cardan & rigging box, shearing of spine for coupling, sticking of Cardan shaft course of action, advancement of hole between torque limiter plates, breakage of apparatus box torque arm pin top securing stud Cardan shaft framework and harm of fork arm jolt gave in the arrangement of Cardan shaft .

Failure of The Cardan Shaft Arrangement

                                                                                                                                                               Broken shaft & Damaged Gear Box




BELT DRIVEN PM ALTERNATOR

In LHB type Coaches,FIAT Bogies are used with Axle mounted Disc brakes. In these bogies the existing 25KW alternators cannot be fitted due to space constraints. Railways therefore tend to look for the alternative. The Permanent Magnet (PM) alternator were alredy know and hence gave a lead in this direction. The PM alternator are smaller in size and can be fitted in these bogies.

This specification covers the design, development, and supply of 30 'KW 'V'-belt driven bogie mounted permanent magnet brushless alternator required for LHB broad gauge air-conditioned coaches.

The advantage with permanent magnet is due to reduction in the size and a reduction in overall space, size, weight, efficiency, durability and much more than the Cardan shaft arrangement.

But the installment progress of the system is slow for two reasons 

1. Only one source of Production.
2. Jacking up of the Prices in international market as it can be a rising demand of source of power generation in rakes due to size factor.

MID AXLE PM ALTERNATOR

This arrangement was indigenous and was took up by Rail Coach factory , Kapurthala itself.
RCF took activity of creating of Permanent Magnet Alternator fitting the rotor specifically on the pivot of the wheel itself. The rotor comprises of a strong center with inserted perpetual magnets with no field windings. The stator is in two parts and gave on the hub the assistance of split course on both sides of the alternator. The stator is held in position with a response bar, which is secured with the stator toward one side and bogie on the flip side. There is no belt drive in this framework.

(p.c- railelectrica.com)

The most imperative issue of the configuration was that if the bearing fails, it brings about immobilization of the coaches, most extreme state of configuration failure and venture failed.




CONCLUSION

Hence The only way to power these coaches is by EOG system as the SG design not yet successful.

NOTE: THE NEW EOG (GENERATOR CAR) SYSTEM FOR RUNNING NAC or A MIX OF AC/NAC IS ON TRAIL. DETAILS FOR THE SYSTEM WILL BE POSTED IN OUR NEXT POST.