3.7. ELECTRIC LOCO ASSEMBLY SHOP (SHOP-18)

3.7.1. INTRODUCTION

This shop (ELB-18) is mainly concerned with Bogie assembly. Three main assemblies are done here namely: motor wheel assembly, braking arrangement and gear assembly.

There are two types of loco assembly

1. Shell assembly (upper)2. Bogie assembly (lower)

3.7.2. Types of loco are:-

1. WAP4: Casted Co-Co bogie.2. WAP5: Fabricated Bo-Bo Bogie.3. WAP7: Fabricated Co-Co Bogie.4. WAG7: Fabricated Co-Co Bogie.5. WAG9: Fabricated Co-Co Bogie.

There is manganese liner on the Exterior for protection from wear and tear. Sand box is provided for Gripping purpose at gradient level. There is brake rigging on wheels to provide Breaking arrangement on loco.

3.7.3 Braking arrangement

It consists of:-

12 lever with brake shoe and brake head assembly. 4 air brake cylinders. Upper slack adjuster. Bottom slack adjuster.

3.7.4 Braking assembly

It consists of:-

Motor wheel assembly. Equalizer. Compensator. Sandwich. Hydraulic damper.

3.7.5. Motor wheel assembly

It consists of:-

1. Motor:I. Hitachi-1: for WAP-4 & WAG-7.

II. 3-phase motor for WAP-5, WAP-7, WAG-92. Wheel assembly:

I. Axle.II. Bull gear.

III. Suspension tube.

Gear assembly

It consists of:-

Pinion and bull gear mess up. Cadmium compound. Trial runway. WAP-4 and WAG-7 has 3-phase DC motors, while WAP-5, WAP-7 and WAG-9 has

3-phase AC motors.

The ratio of teeth between Bull and Pinion for WAP-4 is 23:58 while that for the WAG-9 is 1:55. WAP-5 has an intermediate gear also which have 35 teeth. In this loco, the motor is only connected to the bogie.

In primary suspension there are 8 inner and 8 outer springs. Backlash of 0.8-1.2 is provided for wheel motor assembly. Pinion which is attached to the motor is actually making an interference fit with the

shaft. So to heat it uniformly induction heating is provided. Interference fit should be 1.79 to 2. In WAP-4 ad WAG-7, it is difficult to fit motors as motors are in vertical upstanding

position. Bolster is used only in Rajdhani for turning the bogie. In WAG-7 square shape hole is there, in which Liner is inserted which helps in

turning frames. WAP-5 have helical gear but WAP-4 have spur gear.

RATINGS OF HITACHI MOTORSERIES: WOUND

PULSATING CURRENT DC TRACTION MOTOR

Ratings RPM VOLTS AMPS SHAFT OUTPUT IN

KW

Continuous Rating 895 750 900 630

1 hour Rating 877 750 960 670

Maximum value 2150 900 1350 .....

LUBRICANT USED IS PD2. Cooling air:800 m3/min. No. of poles:6 despatch Axle Box of WAP5 and WAG9 is made of aluminium. WAG9 have twenty four levers:

I. 8 outer lever.II. 8 cylinder lever.

III. 8 centre lever WAG9 has 12 primary springs and 8 secondary springs. Peristal cap, guard assembly and connecting rod are attached to the Bogie

assembly.

3.8 ELECTRIC LOCO SHOP (SHOP-12)

3.8.1 INTRODUCTION

In this shop, ELS-12, fabrication of cab assembly and roof assembly is done with the help of MMAW or GMAW as per the loco being fabricated. In WAG-9, WAP-7 and WAP-5, GMAW is used while in WAG-7 and WAP-4, MMAW is followed.

INSTRUCTION FOR FABRICATION OF CAB ASSEMBLY

(FOR WAP-4)

Shear to size.

Bend to shape

Assemble on structure assembly on fixture and weld.

Oxycut the components

Panel on structure assembly and weld.

Fit all the components and weld.

Inspection

Dispatch.

INSTRUCTION FOR FABRICATION OF CAB ASSEMBLY

(FOR WAG-9,WAP7and WAP5)

Oxycut the components Shear to size components

Bend to shape Bend to shape

Assemble shape, rear wall,CAB roof,

Side wall with front pillar can’t rail

Assemble CAB structure

assembly on fixture and weld.

Fit all small components

(inside and outside & weld)

Inspection

Dispatch

INSTRUCTION FOR FABRICATION OF ROOFS

Shear to size.

Bend to shape

Assemble roof structure assembly on fix.

Panel on structure assembly and weld.

Fit all the components and weld.

Inspection

Dispatch.

3.8.3. The Welding process:

The electric holder is connected to the negative terminal of the power source but it should be connected to positive electrode in case of low hydrogen electrode, only then the power source is switched on and the current is set. Range of current (in amperes) depends on the thickness of the welding required.

INSTRUCTION FOR WELDING OF WAG7 CENTRE PIVOT

Grind the oxycut hole of base plate Place the base plate on the loco

to correct size as per relevant under frame and align the base

drawing. plate hole, under frame bottom

plate hole and centre pivot

as per relevant drawing.

Track weld centre pivot

with base plate

Fix the base plate with the table Remove the rack welded

By intermittent welding to arrest centre pivot with base plate

Distortion during welding of centre pivot from underframe and place

on the table.

Weld the centre pivot

with base plate

carry out ultrasonic test

by NDT perssonel.

Place the welded centre pivot on

Remove the welded centre pivot the underframe,realigned, and weld

from table base by grinding. the base plate finally with bottom

plate of underframe.

FLOW CHART FOR ASSEMBLY OF WHEEL SET OF ELECTRICLOCO BOGIE

3-Phase Conventional

Raw axle Raw wheel

Facing and centring Boring Facing and profiling

Turning Back facing Boring

Grinding Inspection Back facing

Radiasing Ok Inspection

Drilling Rectification No Ok

Yes

Inspection Wheel pressing (left side)

Ok No Rectification Wheel pressing (right side)

Gear pressing Axle box assembly

Inspection

Gear hub truing Tubing Wheel pressing Dispatch