why solar panels are fixed on every box of demu engiene
Answers
Self Generating (SG)
2×25 kW alternators for AC coach and 1×4.5 kW for non-AC coach is mounted underslung, driven by a pulley-belt arrangement when driving pulley is mounted on coach axle. Output is rectified and charges 110V DC battery for continuous power supply to AC and non-AC coaches. AC load of roof mounted packaged units is supplied by converting DC into 2×25 kVA inverters. This system is followed over trains having a combination of AC and non-AC coaches.
End-on-Generation (EOG)
Two power cars each equipped with 2×750 kVA DG sets, one at each end of the train, supplies 3 phase power at 750 V AC power to each electrically interconnected air conditioned coach. The voltage is stepped down to 3 phase 400 V and supplied to standard voltage equipment on each coach. EOG system is followed for fully air conditioned train like Rajdhani, Shatabdi, Duranto, Garib Rath, Premium special trains. Import of LHB class of coaches from Germany is provided with the EOG system with a promise to provide SG system design for indigenous manufacturing. SG technology given was a complete failure and IR is still struggling to develop designs for the last 15 years.
Head-on-Generation (HOG)
Power is supplied from the train locomotive at the head of the train. The single phase 25 kV transformer of the electric locomotive is provided with hotel load winding which is converted to three phase AC at 750 V using 2×500 kVA inverter and supplied to the same system as that of EOG. In case of Diesel Locomotive, three phase alternator is mounted on the traction alternator and feeds the hotel load. This is the most efficient system as the cost of power is about 25% less as compared to EOG, but the system is still under development for the last 30 years. The other class of trains namely Electrical Multiple Unit and Main Line Electrical Multiple Units employs the same system for coach lighting. The system is similar to what is followed in train-set composition of train having a power unit at head as well as on tail and power the entire load of the coach for comfort.
Running of mixed LHB design AC and non-AC coach
There is a need for running a mix of AC and non-AC coaches with LHB coach design to improve passenger satisfactory, higher capacity and improved riding with less maintenance. RCF has already started manufacturing Non-AC LHB and 276 such coaches have gone into service till 31st March 2014 and working on Northern Railway, North Western Railway, Western Railway, East Central Railway and Eastern Railway. The only way to power these coaches is by EOG system as the SG design not yet successful. The electrical load of the train is about 250 kW and with a diversity factory of 80%, system loading will be around 200 kW for which the existing power cars is of over capacity.
Development history of SG AC LHB coach
For manufacturing of Non-AC LHB version, M/s LHB provided Indian Railways a design for driving the alternator with cardon shaft arrangement as per the terms and condition of the contract.
Cardon Shaft Arrangement
In this arrangement, 25KW alternator was of conventional type except belt transmission replaced with a cardon shaft which was driven by a gear box mounted on the axle. The alternator was mounted on the coach underframe to take care of space constraints in the bogie. This design was given by LHB to RCF as per the contractual condition. Based on this design, one rake was turned out to work in Shalimar rake (4545/4646).Screenshot - 20-09-2014 , 09_21_32 The rake turned out by RCF worked between NDLS & JAT for few days but design lapses surfaced out within a short period. The design lapse was non-damping of vibrations emerging from the track irregularities resulting failure on account of breakage of gear box & Cardon shaft, failures of fasteners provided for coupling of Cardon & gear box, shearing of flange for coupling, jamming of Cardon shaft arrangement, development of gap between torque limiter plates, breakage of gear box torque arm pin cap locking stud in Cardon shaft system and damage of fork arm bolt provided in Cardon shaft arrangement.