EN-B (4th year)
1. Axle Driven System
2. Mid On Generation(MOD) System
3. End Of Generation(EOD) System
4. ALTERNATORS USED IN COACHES
5. BATTERIES USED IN TRAIN
AXLE DRIVEN SYSTEM
In this system 4.5 KW brushless alternators
are driven through V-belts from axle.
Lead acid batteries 11O V, 120 Ah arranged
from 3 cell Mono Block units.
Four numbers of emergency feed terminals
boxes for B.G. and one number for M.G.
coach are provided on each end wall for
interconnecting the coach to adjacent coach
to receive power, in the case generation fails.
For BG AC coaches, 18 KW / 25 KW brushless
alternators are used.
Two such alternators are used in AC-2T /AC-
3T /Chair Cars and only an alternator is used
in First AC coach.
Batteries of 800 / 11 00 AH capacity at 10 hr
rating are used in I AC / AC-2T / AC-3T
/chair car of B.G. Coaches.
Output from alternator mounted on the bogie of coach is fed to the
regulator cum rectifier for rectifying the AC output to DC and
regulating the output voltage at different speeds and loads.
The output from rectifier cum regulator on the under frame is brought
through cables on the coach.
The load is fed through four rotary switches (RSW) and fuses
connecting circuits LI, L2, F and SPM.
LI feeds the essential lighting load like lavatories,
gangways, doorways and up to 50% of light in each
compartment/bays corridor lights and night lights, L2
feeds remaining lighting loads, F feeds the fan load
and SPM feeds emergency feed terminals (EFT).
An external battery charging terminal (BCT) is provided to charge the
battery from external charger, if battery is in rundown condition due to
failure of alternator.
MID ON GENERATION(MOD)
SYSTEM In this system a power car housing
DG sets is used in middle of rake.
It is chosen for small branch line
slow trains having long halts
where batteries are likely to
remain undercharged if
conventional axle driven system is
Capacity of DG set will depend on
composition of rake (usually 30
KVA) and generation is at 415 V, 3
phase, 50 cycle and is stepped
down to 110 V, 3 Phase, 50 cycles.
END OF GENERATION(EOD)
SYSTEM Rakes of Rajdhani / Shatabdi express trains having
heavy load of air-conditioned coaches, pantry cars
with electrically operated cooking appliances, use
Diesel Generating Sets housed in coaches known as
Power cars to meet the load.
Normally 2 power cars, one on either side of rake,
generate power at 750 V AC or 415 V AC, 3 phase, 50
All the coaches of power cars are interconnected
with each other through couplers consisting of
switchgear flexible cables.
ALTERNATORS USED IN COACHES
(1) 4.5 KW, 120V BG non-
(2) 3.0 KW, 120 V for MG
(3) 12.0 KW, 120 V for MG
AC coaches / Jan Shatabdi
Non AC Coaches.
(4) 18.0 KW, 130 V for BG
AC coaches (old)
(5) 25 KW,130V, alternator
for BG AC coaches (new)
Approved manufacturers for the alternators are:
KEL (Kerala Electrical & Allied Engineering Industries)
BEACON ( Best & Crompton)
SIL ( Stone India Limited)
CGL (Crompton Greaves Limited)
Some new makes are also coming up like PIPL, STESALITE, IEC etc
BATTERIES USED IN TRAIN
Conventional Lead Acid Cells .
Valve Regulated Lead Acid(VRLA) Batteries / SMF
CHARGING OF BATTERIES
1. Initial Filling:-
Remove the vent / filler plugs and fill the cells, with the
previously prepared and cooled electrolyte, till the lower
marking on the float indicator stem just appears above the
The approximate quantity and gravity of the electrolyte for
initial fillings are given in the reference table.
After filling, allow the cells to rest for a period of around 16
- 24 hours.
During the rest period there will be some fall in the level of
electrolyte. Restore this with some more electrolyte, before
putting the cells on first charge.
Now the cells are ready for first charge.
2. First Charge:-
Select a D.C. source of 50% higher voltage and current capacities as compared to
the battery voltage and maximum current requirement. Connect the positive of
the source to the positive of the cell battery as marked on the terminals and
negative of the source to the negative of the cell / battery also as marked on the
Now charge the cells at the specified rate for 80/100 hours as indicated in Table
During the charging it is not advisable to allow the temperature of the
electrolyte to exceed 50 degree C. So, should it cross 45 degree C, reduce the
charging rate to half the value and increase time proportionately. If the
temperature continues to rise towards 50 degree C, stop charging immediately,
and recommence only after the electrolyte has cooled down below 50 degree C.
The total charge input should equal Time x I (where I is the specified charging
While charging, there will be some fall in the level of electrolyte due to loss of
water by gassing. Restore this at intervals, say 24 hrs. by adding required
quantity of approved quality of water into the cells.
It is necessary to start adjusting the sp. gravity of electrolyte to 1.215 ± 0.005
(with RPg-800, 1.250 ± 0.005) corrected to 27 degree C, at about 10-hours prior
to the completion of charge; so that the adjustment is complete before the
completion of charge.