Presentation on MEMU

Introduction

• The Mainline Electric Multiple Unit or MEMU

is a commuter rail system in India operated by the

Indian Railway for semi-urban and rural areas.

• MEMU trains are designed for semi-urban and

rural areas, unlike EMU trains that are designed

for urban and semi-urban areas. MEMU trains

also have end vestibules not found on EMU

trains. Also, unlike EMU, MEMU trains have

lavatories.

Block Diagram of MEMU

Pantograph (4.5-7.0 Kg/cm2)

• A pantograph is anapparatus mounted on theroof of MEMU to collectpower through contact withan overhead catenary wire.

• It is a common type ofcurrent collector.

• Typically, a single wire isused, with the returncurrent running through thetrack.

Current Transformer

• IT is used to measure the value of current coming from the catenary wire.

• Its location is below the VCB .

VCB (400A, 30KV)

• A circuit breaker is anautomatically operatedelectrical switch designed toprotect an electrical circuitfrom damage caused byoverload or short circuit.

• Its basic function is todetect a fault condition andinterrupt current flow.

• Unlike a fuse, whichoperates once and thenmust be replaced, a circuitbreaker can be reset toresume normal operation

Rod Gap LA (10 KA)

• A lightning arrester is a deviceused to protect the insulationand conductors of the systemfrom the damaging effects oflighting.

• The typical lightning arresterhas a high voltage terminaland a ground terminal.

• When a lightning surge travelsalong the power line to thearrester, the current from thesurge is diverted through thearrestor, in most cases toearth.

(i) Earthing is done for Short circuit as well as for lightning.(ii) Earthing S/w is connected with VCB in order to prevent contact with 25kv supply during maintenance.

Main Transformer (1000 KVA)

• It is used to step-down the incoming supply to 782V, 266V and 141V .

• 782V ------ Tap Changer

• 266V ------ Aux. Motors

• 141V ------ Light & Fan

• OFAF Cooling

Secondary Ckt.

Aux. Circuit

Tap Changer (1000V AC)

• A tap changer is aconnection pointselection mechanismalong a powertransformer winding thatallows a variable numberof turns to be selected indiscrete steps.

• No. Of Steps =22• Shunt 1 to 2• Half Power 3 to 12• Full Power 13 to 22

Rectifier Unit

• It is used to provide inputsupply to DC TractionMotors through Smoothingreactor, ASL and MSG.

• It has Bridge Configurationwith 3000V (PIV) of Diodes.

• Force Air Cooled.

• It is used to provide inputsupply to main compressorand air drier. It is housed inmain rectifier cubical.

• It has Bridge Configurationwith 2000V (PIV) of Diodes.

• Force Air Cooled.

Main Rectifier Unit Auxiliary Rectifier Unit

Rectifier Blower Fan

Smoothing Reactor

• It is a inductive filter used to remove the ac content from the main rectifier output.

• OFAF cooling common with 1000KVA Main Transformer.

ASL

• IT is used to remove the left over AC content called ripples present in the electrical power received from smoothing reactor.

Traction Motors (535V, 1260rpm)

• Traction motor used in MEMU is DC series compound motor.

• No. of motors : 04

• Insulation :

Armature– class H

Field --- Class F

Suspension – Axle Hung

Auxiliaries

• Transformer oil pumpRating : 240V , 1.5 h.p.Capacity: 400 ltrsNo. of units: 01 It is used to pump the oil for

cooling purpose.

• Battery 50 lead acid cells each in 10

units 90Ah Rating It gives supply to : Auxiliary compressorDC Emergency lightsSet of panelsTwin beam head lightLED based Tail LightESMON System

ESMON: Energy saving

Monitoring system

i

It is a Monitoring Device which keep record of:

SpeedDistance

Time Energy Consumed

Master Control

• The Master controller remain activated manually and consciously by the driver in case of the driver gets incapacitated and the device is released , the emergency brake shall get applied.

LIGHTS AND FANS

• TAIL LIGHT: 40W (2 Normal and 1 Emergency)

• TWIN BEAM HEAD LIGHT : 300W

• FANS: 65W

FLASHER LIGHT

LED TAIL LIGHT TWIN

MARKER LIGHT

TWIN BEAM HEAD LIGHT

COMPRESSOR

MAIN

• 9.12 KW, 99A, 110V DC

• IT IS USED FOR SUPPLYING AIR FOR ELECTRO-PNEUMATIC BRAKES.

AUXILIARY

• 8.5KW, 110V DC

• PRESSURE 8Kg/cm2

• IT IS USED FOR LIFTING THE Pantograph

STATIC BATTERY CHARGER

• Efficiency is 80% , Power factor is 0.8, used for batterycharging and is placed behind Driver’s Desk

Compressor Static Battery Charger

Relays

PRIMARY OVERLOAD RELAYMOTOR OVERLOAD RELAY

NO VOLT RELAYCURRENT LIMIT RELAYOVER VOLTAGE RELAY

CONTROL GOVEROR RELAYCOMPRESSOR GOVERNOR RELAY

HT RELAYCURRENT BALANCE RELAY

FOR RECTIFIEREMERGENCY LIGHT RELAY

BUCHOLZ RELAYRECTIFIER FAN RELAY

TRANSFORMER THERMOSTAT RELAYBREAKER RESET RELAY

AIR BLAST RELAYDEAD MAN RELAY

Inter Vehicular Coupler

No. Of Jumpers 04 with 19 cores

03- lights and Fans

01- Main Control

Bogie Motors control section

Smoke DetectorTwin DC DC Convertor for Head Light

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