Lecture 8
RAISING PANTOGRAPH FROM ZERO MR PRESSURE
To raise pantograph from zero MR pressure, select a motor coach where
(i) Battery is available,
(ii) Battery is fully charged & min. battery voltage is 90V
(iii) Baby compressor is working
(iv) Baby compressor is building up the pressure,
Further procedure is as follows:
Close MR coupling cock on both of the leading motor coach (or the motor coach selected )
a. All the drain cocks should be in closed position.
b. Ensure MR main cock should be in open position.
c. In case of ICF rakes (600,700 and 900 series) where 3 way cock is not provided, close screw down cock. In other stock screw down cock should be kept open.
d. Turn 3 way cork if provided towards baby compressor side.
e. Ensure auxiliary HT compartment and HT compartment is properly closed.
f. Operate panto magnet valve to raise position, either electrically or manually.
g. Confirm fan cock and roof cock are open (there is no roof cock in 600, 700 and 900 series).
h. Open baby compressor cock if provided.
i. Switch off four number of auxiliary MCBs, they are MG contactors, MCB, MG retain MCB, compressor contactor MCB and compressor governor MCB.
j. Switch on the baby compressor and watch the panto raising and touching OHE.
k. After the pantograph touched the OHE, started the auxiliaries (MG and compressor one by one.
l. When the main compressor starts, check for any leakage in under Frame.
m. When the MR gauge shows 3.5 Kg/Cm2 turn the 3-way cock towards the main compressor side. When the MR pressure gauge is not available take approximately 1” minute time.
n. Open screws down cock in 600,700 and 900 series.
o. Switch of the baby compressor.
p. Ensure the ICS is off in the leading driving compartment.
q. When the MR pressure built up to 7.0 Kg/Cm2, open the MR coupling cock between 1st and 2nd coaches i.e. between C coach and B coach.
r. Close the MR coupling cock between 5th and 6th coach.
s. Switch off the auxiliaries of middle motor coach by switching off 4 MCBs.
t. Open MR coupling cock between 2nd and 3rd coach.
u. Pantograph of middle motor coach will go up.
v. Switch ON 4 auxiliaries MCBs of middle coach one by one and start MG and compressor.
w. Switch off the four auxiliaries MCBs of 3rd motor coach.
x. Open the MR coupling cock between 5th and 6th coach,
y. Now pantograph of 3rd motor coach will go up when the pantograph touches OHE wire start the auxiliaries of 3rd motor coach by switching ON 4 Nos of MCBs of MG and compressor.
In 12-car rake raise the pantograph of 4th motor coach after switching off 4 MCBs and then starts auxiliaries. Now all the pantographs of the rake is in raised position.
NOTE:-
During practical in KILE CARSHED
1. Drain pressure from all the tanks and start work.
2. If required close BP coupling cocks on both side of 1st motor coach.
3. Do not forget to open BP coupling cocks after the practical is over.
SOME POINTS TO REMEMBERED: -
i) Three-way cock is not provided in 600,700 and 900 series. Supplementary reservoir isolating cock is provided in 800 series.
ii) Auxiliary compressor governor cock is provided after governor in 600,700 and 900 series.
iii) Auxiliary compressor cock is provided before governor in 500 and 800 series.
iv) Roof cock is not provided in 600 and 700 series.
v) For the initial raising of pantograph, closing of screw down cock in 600, 700 and 900 series.
PANTO CONTROL CIRCUITS
This circuit is used to energize panto raise or panto lower coil of panto Magnet Valve. The supply of wire No.16 is given to panto raise and panto lower push buttons, through panto MCB and DCS (Driving Control Switch)When panto raise push button is pressed wire no 8 is energized which energises the raise coil of PMV in all motor coaches. An Interlock of line switch LS1 is included in the circuit of panto raise coil. This prevents the raising of pantograph when the line switches are energies. When the panto lower push button is pressed wire no.9 is energised, which energizes the lower coil of PMV in all coaches. The MG trip coil is connected in parallel to the panto lower coil. A blocker diode is connected in between two coils so that wire no.9 energies panto lower coil as well as MG trip coil. But wire no. 50 of MG trip cannot energies panto