8 WHEELER DIESEL ELECRIC TOWER CAR WITH UNDERSLUNG TRANSMISSION. OPERATING & MAINTENANCE MANUAL (2019)

TRACTION MOTOR

INSPECTION INTERVAL

TRIP

MONT

THRE

SIX

YEARL

TWO

REPAIR

HLY

MONT

YEARL

INSPECTION ITEMS AND

LIMIT OR

MONT

HLY

STANDARD

OPERATIO

HLY

N RANGE

h. Interference fit shall be applied

to inlay of pinion.

Interference Heating temperature :

140 - 160º C above ambient

i. Contact degree of armature shaft

and taper of pinion shall be more

minimum for

than 90 %

used

j. Ultra sonic and magnetic particle

testing shall be carried out about

shaft.

3. STATOR

3.1 Magnet frame

a. Dimensions of mounting parts

(as shown in drawing)

b. Lead wire with damaged

covering or damaged terminal shall

be replaced.

Less than

c. Damage of core of lead wire and

connector may be used

3.3 Brush holder and Carbon Brush

a. Cleaning and check

b. Spring pressure (at assembly) at

2.50 to

3.30

At Brush height 57 mm : 3.20 kgf

kgf/brush

/brush

At Brush height 32 mm : 2.80 kgf/

brush

c. Dimensions of brush holder

pocket

20.3 mm

Thickness : 20.00 mm

Width : 40.00 mm

40.3 mm

MAINTENANCE MANUAL FOR DETC-US

TRACTION MOTOR

INSPECTION INTERVAL

TRIP

MONT

THRE

SIX

YEARL

TWO

REPAIR

HLY

MONT

YEARL

INSPECTION ITEMS AND

LIMIT OR

MONT

HLY

STANDARD

OPERATIO

HLY

N RANGE

d. Clearance between Brush holder

Face and commutator surface

Gap : 2 - 3 mm nominal

Distance between brush end face

and commutator end face : more

than 4 mm

Service length

e. Length of carbon brush

: 25 mm

Exchange

f. Chipping of carbon brush

limit : 32 mm

g. Pigtail breaking of brush

less than 10 %

3.4 Gear Case

a. Check the gear compound level

b. Check the packing of gear case.

Worn packing should be replaced.

c. Gear compound leakage

ASSEMBLY TEST AND

OTHERS

a. Bedding of carbon brush

b. Dielectric test

New

: 2.5 kV, 50 hz for 1 min

1.5 KV/1min

Repaired : 1.5 kV, 50 hz for 1 min

(Repaired)

c. Insulation Resistance test

d. No - load test

Examine abnormal vibration or

More than 1.0

abnormal noise

MΩ

1000 rpm for 1 hour in both

directions.

ii.

2000 rpm for 15 min in both

directions.

MAINTENANCE MANUAL FOR DETC-US

TRACTION MOTOR

NOTES

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MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

CHAPTER VIII

AUXILIARY ALTERNATOR

1. INTRODUCTION

KEL Alternators type KELA 121125 FM are designed to be driven with a cardan shaft coupled directly to the

diesel engine through flexible coupling. The alternator with associated regulator rectifier unit delivers 8 KW

power at a constant voltage of 120 ± 5% from no load to 74 A load at all notch positions of the engine.

The system consists of a Brushless inductor type alternator and a completely static regulator rectifier unit.

The alternator is completely devoid of any type of moving coils or sliding contacts and this ensures a trouble

free operation without practically any maintenance.

The regulator - rectifier unit makes use of silicone diodes, and “Magnetic Amplifiers”. All the components

used in the rectifier - regulator unit are unlike transistors and thyristors-tailor made to the requirements of the

hazardous application to which they are put in Rolling stock. As such the reliability of KEL generating

system is high.

2. DESCRIPTION:

The statodyne type KELA 12125 FM is a totally enclosed machine developing a constant voltage of 120V (

±5% ) at a maximum load current of 74 Amps DC.

The machines are used for :

Charging of 110 Volts battery provided on the car.

II.

Light and fan loads of the coach

III.

Control system (20 Amps)

IV.

Head light of 750 watts at 32 volts, the voltage being dropped through a resistor from 135 volts

DC.

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

2.1 Generator data

Rated Capacity

8 KW

Type

KELA 12125 FM

Mounting

Foot Mounting

Enclosure

Totally Enclosed IP 55

Cooling

Self cooled

Minimum speed for full output

700 rpm for 70A at 120 Volts.

Maximum speed

2000 rpm

Weight of Alternator

302 Kg

Class of insulation :

a) Stator

Class H

b) Field

Class H

Type of Bearing :

a) Drive End

NU311

b) Non drive End

6311

Resistance between two phase

0.198 Ohms ± 5%

Field Resistance

12.98 Ohms ± 5%

2.2 Rectifier-Regulator Unit :

Type

KEL C 12125 FM

Full load

64 A

Voltage setting

125 V at 32 A at 1500 rpm

Max load

74 A

Class of insulation

Weight of Regulator

52 Kg

The rectifier regulator also is a totally enclosed unit. It consists of:

A power rectifier comprising of :-

a. One full wave, three phase bridge connected rectifier, using six silicone diodes.

b. Capacitors to protect the rectifier diodes from surges and to filter the DC output.

ii. A regulator rack consisting of :-

a. One field transformer

( FT )

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

b. One magnetic amplifier

( MA )

c. One Field rectifier unit

( D3, D4 )

d. Two voltage detectors

( DT1 & DT2 )

e. One free wheeling diode

( D5 )

One burden resistance

( RBI )

g. Two blocking diodes

( D1, D2 )

iii. Three current transformers connected in star for sensing the load current

(CT1,

CT2 &

CT3)

The phase and field fuses are provided on the rectifier board of the regulator.

The labels provided for terminals on the terminating portion of the regulator as follows.

U, V, W

AC input to Regulator from Alternator.

+DC, -DC

DC output from regulator

Output field terminals from regulator to alternator field coil terminals.

3. PRINCIPLE OF OPERATION

3.1Generator

As mentioned above the statodyne generator is a three phase, homopolar, inductor type alternator without any

rotating, commutator or sliprings. The field windings and AC windings are located in the stator. The field

coils are concentrated in two slots.

Each field coil shares half the total number of stator

slots.

Outline drawing of 8 kW Auxiliary alternator

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

Details of Coupling Flange

The rotor is made up of silicon steel laminations and resembles a cogged wheel. The teeth and slots are

uniformly distributed on the rotor surface.

The core of the stator, completely embraced by the field coils will retain a small residual magnetism if excited

by a battery. The flux produced by the field coil finds its path through the rotor and when the rotor is rotated

the passage of rotor teeth and slots under the field offers a varying reluctance path for the flux produced by the

field coils. This flux varying periodically also links the AC coils and induces an alternating voltage in the AC

coils. The frequency of the voltage depends on the speed of revolution of rotor and the magnitude is decided

upon the speed as well as strength of field.

The field is strengthened by a positive feedback system in the regulator. Thus when the rotor is rotated the

residual magnetism will cause an induced e.m.f. in the AC coils, which is strengthened further by the positive

feedback to the field. The voltage rises till it is a controlled by the regulator.

The AC coils are connected in star and six output leads are brought to the terminal board on the alternator.

3.2 Power - Rectifier

This consists of six silicon diodes connected in three phase full wave bridge. The three phase output of the

alternator is rectified by these diodes to give a DC output at terminals + DC and -DC.

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

Outline drawing of Rectifier Regulator Unit

Each diode is protected against transient surges voltage by capacitor C1. The whole bridge is protected against

high frequency surges by capacitor C3. The DC output is filtered by capacitor C2.

3.3 Current Transformer

The current transformers are used to sense the load current for the current limit. When the primary winding of

each current transformer carries load current, the secondary winding feeds a three phases voltage to the

rectifier RT2 in the regulator rack.

3.4 The regulator rack

The regulator rack consists of the following parts.

3.4.1 Excitation Transformer

This is a one winding transformer with tappings for input and output. The transformer steps down the voltage

for the field coils. The output of the transformer is taken in the field through the magnetic amplifier before

being rectified by field rectifier diodes.

The transformer has five set of terminals.

Terminals 14 & 15, input from phase 14 & 15 of alternator. Centre tapping, terminal 19, goes to the -ve

terminal for field supply.

Terminals 18 & 161 are the output terminals and go to the respective terminals on the magnetic amplifier.

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

3.4.2 Magnetic Amplifier

The magnetic amplifier forms the nucleus of the regulator circuit; It works on the principle of saturation of

magnetic core. The equipment has six sets of windings:

Two load windings:

18 - 162 & 17 - 161

Four control windings:

10 - 11, 26 - 27, 29 - 30 & 20 - 40

(Of these only 10-11 and 20-40 are used in the circuit.

10-11 for voltage and current control & 20-40 for gain

control).

The field current passes through the load windings of the magnetic amplifier. Subject to the command from

the voltage and current sensing circuits, manifested through the control winding 10-11, the load winding offers

variable impedance of the field circuit.

3.4.3 Field rectifier unit

The two silicon diodes D3, D4 acts as a full wave rectifier for the field supply. These diodes conduct

alternately. The rectified current from the diodes is taken through the feedback winding 20-40 of the

magnetic amplifier. Terminals 20 & 19 form the +ve & -ve terminals form the field assembly.

3.4.4 Free - Wheeling Diode

In the normal circumstances this diode D5 has no function. But should there be any reason for a surge from

the field circuit which will have a polarity opposite to that of excitation, this diode will conduct avoiding

creepage of the surge voltage to more important components like Magnetic Amplifier.

3.4.5 Rectifier Bridge

Each bridge RT1 & RT2 is made up of six silicon diodes, connected for three phase full wave rectification,

RT1 supplies the rectified voltage for voltage detector DT1 which is also the voltage developed by the

alternator, RT2 rectifies the three phase voltage developed at C.T secondary side and supplies to the voltage

detector DT2.

3.4.6 Voltage Detector DT1, DT2

These voltage detectors serve the function of providing necessary “error signal” for voltage regulation &

current limiting.

It consists of a network of zener diode, potential divider & rheostat. The voltage drop across resistance can

be adjusted by varying the resistances Rh1 & Rh2.

In the case of DT1 when the output voltage exceeds the voltage of the alternator the voltage drop across R1

will be sufficient to cause zener break down and this will send a current through the control winding 10-11 of

the magnetic amplifier.

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

Similarly, in the case of DT2, when the current reaches preset value the voltage induced in the secondary of

the current transformer after rectification by RT2 will be sufficient to cause conduction of the zener diode

and to produce the necessary error signal to magnetic amplifier for current control.

Zener diode has a characteristic that the diode starts conducting only at a designated voltage (zener voltage).

The voltage across the zener will be maintained even if the voltage input to the circuit is increased. Thus it

serves as base for comparison.

3.4.7 Blocking diodes

Diodes D1 & D2 are used to block the current from one zener to the other. Diode DI prevents creepage of

current from DT2 to DT1 and D2 prevents current from DT1 to DT2. This is achieved by the unidirectional

property of diodes.

3.4.8 Regulator failure relay

One number over voltage under voltage relay is provided to indicate the failure of the regulator. When

output terminal voltage of the regulator drop below the pre-set value the relay trips and indication lamp will

glow. And same in the case of over voltage.

3.4.9 Regulator failure indication lamp

One number indication lamp is provided to show the failure of the regulator. This is connected in series with

the battery and the contacts of the regulator failure relay.

4. WORKING OF REGULATOR

The three phase output from the alternator is rectified by the bridge connected silicon diodes. The DC

excitation to the field is obtained by full wave rectification of alternating current provided through the load

windings of the magnetic amplifier.

The voltage induced in the alternator winding depends on the speed of revolution of rotor and on the

excitation current. In the absence of voltage detector and magnetic amplifier, the voltage of the alternator

will rise indefinitely due to the positive feed back limited only by saturation of stator. But as soon as the

preset voltage is reached the zener diode in detector DT1 conducts and sends a control current through the

magnetic amplifier winding 10-11. The flux produced by the control current is in such a way that it opposes

the flux produced by the load windings, there by increasing the impedance of the field circuit. This increase

in field impedance reduces the field current and feed back the output voltage to the normal value required.

The current limiting is also achieved in a similar manner. When the pre-determined load current is delivered

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

by the alternator, the secondary voltage of the CT after rectification by bridge RT2 will provide the necessary

“error signal” for the magnetic amplifier. In this case also the voltage drop across the resistance will be

sufficient to cause the zener diode in DT2 to conduct. The control current from this also passes through the

same control winding 10-11. The effect of this control current is to retain the current at the limited value and

to reduce the voltage. For a sustained overload, the generator voltage will fall to the battery voltage &

relieve the alternator immediately, thereby reducing the chances of damage due to the load.

5. ROUTINE MAINTENANCE

5.1Alternator :

• Check the suspension and securing nut after every round trip.

• Inspect the terminal box for water tightness.

5.2 Regulator box

See that all securing fasteners are held properly

Keep the cover tightly closed.

Ingress of water and dust in the regulator box will damage the equipment beyond repair.

6. PERIODICAL OVERHAULING

6.1Alternator

• Clean and regrease the bearing after removing the bearing from the bearing housing. The bearing

is designed for regreasing in workshops at long intervals of 5000 hours in operation. However, it

is recommended that during POH, the bearing should be regreased.

• Before using new grease the bearing should be thoroughly cleaned with white spirit. 24 gms. Of

lithon 2 should be used for refilling.

• The bearings should be changed, if it is found defective during inspection.

• Clean the mating surface of the end shield, before assembly the surface should be coated evenly with

gasket shellac.

• While removing and placing the rotor, care should be taken to see that the rotor does not rub over the field

coils.

• If any grease has crept into the stator surface clean it before assembly.

• If stator & rotor parts are found rusty, clean and slightly coat with Dr. Beck make E1mo65E/R insulating

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

varnish.

6.2

Regulator box

If no failure or defect has been observed, clean & tighten all components and ensure that all joints and connections

are properly tight.

7. REMOVAL OF ROTOR & BEARINGS

The following procedures should be adopted for dismantling alternator.

a. Remove the fan cover from one end after removing the M10 screws.

b. Using a box spanner of size 13 unscrew the two screws securing the screw locking washer.

If these screws have been locked by steel wires or by tack welding,

proceed only after removing the locking arrangement.

Remove flange from the shaft.

Bend back the SKF lock washer M8 12 from DE side

Remove lock nut SKF KM 12 from DE side.

Remove all the end shield fixing screws from NDE side.

Locate the two tapped holes on the endshield on NDE side along with the rotor and bearing on NDE

side and screw in two M I0 screws. The two screws should be turned in equally, as the screwing

progress the endshield comes out gradually along with the rotor bearings on NDE side. The endshield

and bearing on DE side remain and in its place.

Gently pull out the rotor from the stator. Care should be taken to see that the rotor does not pull over the

stator coils.

After removing the endshield fixing screws from NDE side, remove the end shield by screwing into

M10 screws in the tapped holes on the endshield.

The endshield on NDE side now lies along with the rotor. Bend back the lock washer M8 12 & remove

the locknut KM 12. Remove the bearing covers. Remove the spacer, pull out the end shield from the

shaft. The end shield comes out along with the bearing. (The inner race remains on the shaft).

The bearing can be removed from the end shield by gently pressing out, in a hydraulic press. The

pressure should be applied gradually.

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

The inner race can be removed by slightly heating the inner race by using an induction heater. The ring

comes out of the shaft on slight knocking.

8. ASSEMBLY

Assembly of the alternator can be proceeded on the reverse way with special care on the following points:

a. The inner race of the bearing should be heated in an oil bath at about 80 deg. C to 90 deg. C

before insertion on to the shaft.

b. The end shield should be heated in an electric oven to about 120 deg.C before locating the

bearing in it.

c. In order to seat the bearing properly internal bearing cover should be fixed on to the end shield before

heating the end shield.

d. Before inserting the bearing to the shaft, the internal bearing cover should be placed in its position.

e. If this is not done it is impossible to assemble the machine

Gasket shellac (Addison) should be applied evenly on all the mating surfaces of bearing cover and end

shield.

g. Take special care to see that the bearing comes on the terminal box side.

h. While removing and fixing the SKF lock nuts use a hook spanner. Never use any tools for this purpose

The cooled bearing put in back to back arrangement is placed inside the heated endshield and outside

bearing cover assembly. The whole thing is then inserted into the shaft, which will mate with inside

bearing cover.

9. DO’s AND DON’Ts FOR THE EQUIPMENT

A. ALTERNATOR

a. Open up the terminal box once in two weeks and clean up the dust if any accumulated in it.

b. Check up the tightness of connection once in two weeks.

c. Keep the terminal box tightly closed

d. Regreasing should be made after thoroughly cleaning the bearings with while spirit. It is preferable to

regrease the bearing only during POH.

e. Don’t overgrease the bearings.

The field connection on the alternator terminal box should not be reversed.

g. Use the cable sockets and cable glands for connections.

h. Never give separate excitation to the field. It will damage the regulator components.

B. REGULATOR

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

a. Don’t disturb the setting on the voltage and current potentiometer. Best results are obtained with the

settings made by the manufacturer.

b. Don’t open the regulator box unless a defect is observed.

c. Don’t use a megger to test the components. Use a multimeter.

d. If earth resistance is to be measured, disconnect the leads from alternator and load.

e. Short circuit all the seven terminals, before using a meggar.

Don’t reverse the field terminal connections.

g. If a diode is to be replaced its base should be evenly coated with silicon grease.

h. In no circumstances the burden resistance setting should be disturbed.

Use only HRC fuses in phase and field circuits

MAINTENANCE MANUAL FOR DETC-US

AUXILIARY ALTERNATOR

NOTES

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MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

CHAPTER IX

CONTROL GEAR ITEMS

Master Controller

Master Controller is used to select various speed of Diesel Engine as well as to change the direction of

vehicle. It has two handles, which function is explained below:

i) Accelerating Handle:

This handle has nine notch positions i.e. 0-1-2-3-4-5-6-7 & 8. The vehicle will accelerate as the driver moves

the handle from a lower notch to a higher notch.

ii) Reversing Handle:

It has three positions i.e. REVERSE - OFF - FORWARD. The position of this handle decides the direction of

movement of train.

A locking key is also provided. Reverse Handle can not be operated unless the locking key is inserted in the

keyhole & rotated by 90^o clockwise.

Mechanical interlocking is provided to prevent unauthorised operation of either accelerating or reversing

handle. It has following features:

I) Reverse handle can be moved to either

“Forward” or

“Reverse” position only when the key is inserted

inside the keyhole & rotated by 90^o clockwise.

ii) Accelerating handle can be moved only when reverse handle is either at “Forward” or “Reverse" position

i.e accelerating handle cannot move when reverse handle is at “0” position.

iii) Reverse handle can be moved only when the accelerating handle is at “0” position.

iv) A deadman’s mechanism is provided with the accelerating handle. When the accelerating handle is

depressed deadman contact closes & when the handle is released, it opens to cut off the traction control

supply & thus the power to Traction Motors. The mechanism is so designed such that it trips only when the

“Reverse Handle” is either at forward or reverse position.

v) Key can be removed only after the accelerating handle is brought to “off ” position and reverse handle is

brought to “0” position.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

Make & Type No

Inder Engg., 9MC-MU-018

Operating Voltage

110V DC

Current Rating

10 Amps (Thermal)

Motor Overload Relays

It is used for protection of Traction Motor from current overloading.

The relay has two coils -

a) Operating Coil: It is single turn coil, which passes through the yoke of relay.

b) Resetting Coil: This coil is provided for resetting the overloaded relay to resume normal operation. This

coil is suitable for remote resetting operation.

The relay has six auxiliary contacts (3NO+3NC) for use in control & indication circuits. When the motor

current exceeds the value at which the relay is set to trip, the yoke gets magnetised, which pulls down the

armature of main coil. At the same time armature of reset coil is released and position of auxiliary contacts is

changed.

Thus the supply to E.P.Contactor coil, through auxiliary contacts of overload relay is cut off, which in turn

breaks the power circuit thus preventing the motor from overloading.

Make & Type No

Inder Engg

Current Rating

900 Amps

Reset Coil

DC 110V, 1 Minute

Reset Coil Resistance

160 Ω

Calibration range

600A, 700A, 800A and 900A

Trip Coil Setting

650A.

Capacity of contact (Auxiliary)

Thermal

ii)

Rupturing

0.5A, 110 V.

Min. operating voltage (Hot)

< 66V

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

E.P. Reverser

E.P.Reverser is used to change the direction of field current of Traction Motor, thus changing the direction of

the coach. It is a 4-Pole off load switch, which carries rated current during its operation. It has two sets of

Magnet valves, one each for forward and reverse operation. It has 4 power contacts and 4 auxiliary contacts

(change over type). When forward coil is energised, all 4 power contacts and 4 auxiliary contacts operate &

make connection in forward direction. Similarly reverse connection is made when reverse coil is energised.

Make

Inder Engg.

Rating of main contacts

600 Amps (Thermal)

No. of main poles

4 Nos. (change over type)

Rated Operating Air Pressure

5 Kg/cm²

Rated coil Voltage

110 V DC

Rating of Auxiliary Contacts

10 Amps (Thermal)

Min. operating voltage

68 Volts

Min. Operating Pressure

4 Kg/cm²

Electro-pneumatic Contactor

EP Contactors are required to connect / isolate the Traction Motors to / from the power circuit. These

contactors are On-Load Switches and are required to isolate the motors on load from the power circuit.

These EP Contactors are fitted with a cylinder and piston, which operate main contacts of copper with silver

/ silver cadmium oxide tips. These silver tips are protected from damage due to arcing. A blow-out coil is

fitted to extinguish the Arc when the main contacts are open (on-load) and this is assisted by an arc chute.

When the magnet valve is energised, air is admitted to the cylinder. This causes the piston to rise and main

contacts close.

One set of auxiliary contacts are provided, when the magnet valve is energised the auxiliary contact arm

shall move upwards and shall cause the auxiliary contacts to close.

When the magnet valve is de-energised, air exhausts from the cylinder and the piston moves downwards to

open the main contacts and at the same time the auxiliary contact arm also moves downwards and open the

auxiliary contacts.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

Make & type

Inder Engg., 9-24PC2-15

Operating Voltage

110 VDC

Operating pneumatic pressure

4.5 Kg/Cm²

Main Contacts Rating

1500 Volts, 1390 Amps

Auxiliary Contacts Rating

3Amps @ 110 VDC

Load Ammeter Shunt

Two separate load ammeter shunts are provided one for motor no. 1 and other for motor no. 2 to measure the

motor current.

Rating

1000A / 75mV

Make

AE, Mumbai

Ground Fault Relay

Ground fault relay operates in the event of ground fault in power circuit. It is a current operated relay. Once

the ground fault has occurred, the relay gets latched & it can be reset manually with the help of reset knob

provided on the relay. A cutout switch is provided in series with the relay coil to isolate the relay from power

circuit.

Trip Coil Setting

180-280 mA

Rating of Auxiliary Contacts

5 Amps (Thermal)

Resistance of Coil

630Ω at 20° C.

General Purpose Relay - 1

It consists of General Purpose Relays for sequencing, interlocking & protection.

Make & Type No

Schneider

Coil Voltage

120V DC

Contact Arrangement

4 NO

Add on Block

4 Amps; 2NO+2NC or 4NC

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

General Purpose Relay - 2

Make & Type No

Schneider

Coil Voltage

24V DC

Contact Arrangement

4 NO

Add on Block

4 Amps; 2NO+2NC or 4NC

Resistor Panel

Resistor panel provides external resistance to the exciter stator coils of Traction Alternator for limiting the

excitation current to a safe value in the event of failure of excitation control function.

Make & Type No

PEC; PPR 300

Rating

12 Ω , 300 watts

Bypass switches:

Bypass switches are used to bypass a protection circuit when the corresponding protection circuit is not

working properly or intended to bypass under strict vigilance. The circuits/relays, which can be bypassed,

are listed below with their operating pressure range:

Make & Type No

RGK; 1510.4430

SPST

15 Amps, 250V AC/DC

Driver’s Control Switch Box:

Driver’s control switch box contain switches for various control operations. It has spring-loaded switches as

well as change over type switches.

All the switches in the top row are mechanically interlocked with Driver’s Control Switch removable handle.

The switches can be unlocked by pressing the handle down by 10mm and turning it clockwise by 45 degrees.

The handle can be inserted/removed in OFF position only. Moreover, the top row switches are automatically

reset to normal position when the handle is removed.

10 Auxiliary switches are also provided, which operate when the Key is inserted and kept in ON position.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

Make

Inder Engg.

Thermal Current rating of contacts

10 Amps

Breaking Capacity of Contacts

2Amps inductive Load at 110V DC

Main Switches

2NO + 1NC

Driver’s Control Switch

8NO + 2NC

Lamp rating

125V, 10W

Wire wound Resistor

250 Ω ± 3%, 3W

Engine Control Switch

Engine control switch has two positions namely ‘IDLE’ & ‘RUN’. The switch put-off the excitation of

Traction Alternator there by preventing Power to Traction Motors unless it is switched to ‘RUN’ position &

Master Controller is taken to notch 1 or higher notches.

Make

JSL

Brand Name

JMP

Rating (Thermal)

25 Amps, 500V AC

Contact Arrangement

3NO + 3NC

Load Ammeter and Ammeter selection switch

Ammeter and Selector Switch is provided for indication/measurement of load current. Using selector switch

load current of Traction Motors 1 & 2 can be selected. Motor current of rest of the motor currents cannot be

measured with the selector switch & Load ammeter. Load Ammeter has a basic rating of 75 mV and is

shown in 1000 Amps DC range.

Load Ammeter

Make & Type No

AE; SM144

Rating

0-75mV/0-1000 A

Dimension

144 x 144 mm

Ammeter Selection Switch

Make & Type No

KAYCEE ; RP125B

Rating

16 Amps AC/DC, 2 way with off

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

Motor cutout switch

2 Nos. switches are provided in Control Cubicle to isolate either a single motor or a pair of motors in the

event of fault on Traction Motors. The operational sequence of switches is listed below.

1) MCS-1:

ALL in /Motor 1 out / Motor 3 Out / Motor 1 & 3 Out

2) MCS-2:

All in /Motor 2 Out / Motor 4 Out / Motor 2 & 4 out

“Off” position indicates normal/healthy operation.

Make

KAYCEE (programme Switch)

Rating

16 Amps, 250V AC/DC

No of Poles & Positions

4 Pole & 4 Way

Voltmeter and voltmeter switch

One no. Voltmeter and one no. Voltmeter switch is provided in Control Cubicle, for measurement of system

control voltages 110 V DC & 24 VDC. Voltmeter switch is connected in series with the voltmeters. The

indication on voltmeter is available only when the switch is turned on.

Voltmeter

Make & Type No

AE; SQ96

Rating

0-150V DC

Dimension

96 x 96 mm

Voltmeter switch

Make & Type No

RGK; 1510.4430

Rating

15 Amps, 250V AC/DC

Battery (110V) Cut out switch

This switch is provided to isolate entire control and auxiliary circuit from 110 V battery. 32 Amps & 63

Amps in-built fuses are also provided in the switch.

Make & Type No

Salzer

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

Contact Rating

300 Amps

Reverse Current Diode

Reverse current Diode is provided for protection of batteries against discharging, when

the

18.5 kW

Auxiliary Alternator supply is not available.

Make

Ruttonsha

Average Forward Current

150 Amps

PIV at rated junction temperature

1000 V

Battery (24V) Isolating Switch

Make & type

Inder Engg.

Rating

250 Amps, 415V, 50 Hz

Timers

Make & type

ETR650, Siemens

No. of Changeover Contacts

4 Nos.

Local/Remote Switch

Type & Make

Kaycee (Program Switch)

Rating

16 Amp, 2-pole, 3-way

Instrument Lamp

Type & Make

Siemens, 3SB0420-2A

Rating

110 VDC

Lamp

110 VDC, 2W

Auxiliary Fuse Panel

Type & Make

Siemens, 3NH3 030

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

Rating

125 Amps

Fuse Rating

32Amps, 3NA1001

Fuse Rating

63 Amps, 3NA1015

Hand Lamp socket

Ratings

10 Amps, 3-pin

Miniature Circuit Breaker (MCB)

MCB’s are used to protect electric circuits against overloading caused by excessive currents due to sustained

overloads or short circuits. MCBs are used in CAB-1 and CAB-2.

Make

Schneider

Specification

SPEC/E-12/1/04 & SKEL-3700

Ratings

5A, 10A, 15A & 30 Amps

LED Indication Panel

36 LED Module indication panel is mounted on the Driver’s Desk-DPC. The LED indications are provided

to identify various fault & healthy features of the vehicle.

Make & Type

Inder Engg & 36 LED

Voltage of operation

110 VDC

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR ITEMS

NOTES

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MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

CHAPTER X

MAINTENANCE INSTRUCTIONS

CONTROL GEAR EQUIPMENT

1. INTRODUCTION

ELECTRIC TRACTION EQUIPMENT must be reliable in order to avoid failures, traffic delays and loss

of revenue due to lack of public confidence. The equipment must also operate cheaply for economical

operation in service.

These requirements can only be fulfilled if preventive measures are taken, in the form of periodical

Service Maintenance and Overhaul, which must be thoroughly organised and meticulously and

conscientiously carried out at the times recommended in this Maintenance manual.

The intervals, at which Service Maintenance and Overhaul are carried out, are calculated on the basis of

either time or distance travelled and will depend upon the type of equipment, the nature of service, and

climatic conditions. In the case of diesel-electric equipment, the intervals may depend upon the number of

hours the engine runs.

If the weekly mileage is regular and approximately constant, a time-period basis of maintenance is

probably more satisfactory; but if the weekly, monthly or seasonal mileage is subject to wide variations,

the use of the time period basis would introduce differences in the distance travelled, in which case the

distance basis of maintenance would be preferable.

1.1 Service Maintenance

This is carried out on a regular basis in order to maintain the equipment in sound condition and to prevent

service failures. If maintenance is carried out efficiently at the established periods, the equipment will

operate reliably between overhauls.

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CONTROL GEAR EQUIPMENT

Maintenance is usually carried out in the running shed and comprises examination, cleaning, lubrication,

any necessary adjustments for wear, and changing worn consumable parts such as carbon brushes,

contacts, arc chutes etc. fitting new or re-conditioned parts.

Consumable part must not be allowed to wear beyond the specified minimum dimensions. If it is

estimated that a part will become fully worn before the next maintenance occasion, it must be replaced by

a new or reconditioned part. In addition, a sufficient margin for wear should be allowed in case a normal

maintenance occasion is missed, due to the hazards of severe weather or other unusual traffic conditions.

The intervals at which the various maintenance operations are carried out can only be determined by

observation and experience. At first, the intervals should be about one week or 3200 km, and they should

be lengthened gradually as experience is gained without, of course, endangering the reliability of the

equipment. Eventually, when the maximum intervals have been established, they should, if possible, be

arranged to fit the occasions when the vehicle visits the running shed for maintenance of the mechanical

parts of the vehicle.

1.2 Overhaul

This is carried out in the workshop, and comprises repairing and reconditioning the equipment; that is,

dismantling, replacing worn or defective parts by new or reconditioned components, re-assembling the

equipment and testing it for correct operation.

The periods between overhauls are best determined by withdrawing the equipment for service after a

period of two years or 160,000 km, and subjecting it to a detailed examination, which will also necessitate

a certain amount of dismantling. If it is found that the equipment has not reached the Overhaul state, it

should then be returned to service.

In general, periods between overhaul should not be less than three years. These periods are, however,

capable of being extended to five years or more provided.

Modern high-grade lubricants are used.

Maintenance is efficiently carried out.

Thorough attention is given to cleanliness.

MAINTENANCE MANUAL FOR DETC-US

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Experience on many railways, in different parts of the world, has shown that more frequent maintenance

and overhaul are necessary for the mechanical parts of the vehicle than for the electrical equipment. As

the program for the electrical work must be built up gradually, and the periods extended as experience is

gained, every endeavour should be made to fit the electrical program into the mechanical program, in

order to minimise the time that the vehicle is out of service.

1.3 Records

Accurate records should be kept of the maintenance and overhaul work carried out in order to determine

the amount by which the Maintenance and Overhaul periods may be extended. "Cardex" is a suitable

system for this purpose, and it would contain card for each of the items on which records are to be kept,

for example, armatures, machine stators, gears, pinions pantograph wearing-strips (if fitted), cleaning

filters and radiators, etc.

2. CLEANLINESS

Cleanliness is essential to good maintenance and trouble-free service, and the work of cleaning must be

thoroughly carried out at the established intervals.

Metallic dust from the wheels and brake shoes is detrimental to equipment and, if the dust is allowed to lie

on insulation surfaces or to penetrate coils, it can cause electrical failure.

This dust, when dry, is usually easy to remove, but if it becomes bound with water or oil, its removal is

more difficult. Operators must, therefore, avoid leaving deposits, which have this binding action.

The degree of cleanliness, which can be maintained, depends to a large extent on the location of the

equipment and whether it is totally enclosed, ventilated, or outside-mounted.

When no ventilation is required because the production of heat is low, apparatus is enclosed in dust-proof

cases, compartments or cupboards; ensure that the rubber or felt jointing of the covers or doors is

maintained in good condition.

Ensure that the devices for keeping covers and doors closed are also well maintained and lubricated when

necessary.

Compartments, which cannot be seated easily, for example when they are provided with sliding doors, are

sometimes pressurised with filtered air. When this is the case, it is important to ensure that any failure of

air supply is restored without delay, and the filter is cleaned regularly, or changed when necessary.

Although the frequency of cleaning totally enclosed apparatus is much less than that required for

ventilated or roof-mounted apparatus, it must not be neglected if failure is to be avoided.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

Apparatus such as resistors and rectifiers, etc., which have to dissipate heat to avoid excessive

temperature, are either free-ventilated or force-ventilated with unfiltered air and require frequent cleaning,

as they readily become contaminated with dirt and brake shoe dust.

On electric vehicles on which roof-mounted apparatus is fitted, there are large porcelain insulators, which

may collect much falling dirt and therefore must be kept clean. Rubber hose for the pantograph air supply

must also be cleaned and kept free of oil and grease. Examine all roof equipment and check for

mechanical damage; remove any debris that may have lodged on the roof.

3. LUBRICATION

In general, lubricants should be used sparingly to avoid contaminating insulation and other parts of

apparatus. Clean the electrical sliding contacts of knife switches, drum switches and reversing switches

etc., periodically, then lightly smear them with 4 x grease ( supplied by Dow Corning, USA)

Pivots for contactors and hinged contact fingers, etc., are lubricated during assembly, chiefly as rust

inhibitor prior to being placed in service. Do not add lubricant at periodical maintenance because the

pivots have an extremely long life, even when operating dry, and if lubricants were added it would tend to

contaminate other parts of the apparatus, thus forming a dirt-collecting surface. Lubricate pivots only at

overhaul with grade SAE 30 oil.

Lubricate cylinders, piston, rods, sliding parts and solid (no oil-impregnated) rollers, etc., periodically

with grade SAE 30 oil.

Do not add grease to ball bearing between overhauls, unless otherwise specified in this manual; clean and

re-pack them at overhaul with Shell Alvania 3 or other approved grease. Also use this grease for smearing

the teeth of racks and pinions, and for lubricating sleeve-bearings.

Lubricate oil-impregnated rollers and bearing bushes with grade SAE 30 oil only an overhaul.

Lubricate the hinges on pantograph current-collectors with no-water-soluble grease or oil.

The foregoing information is given as a guide, and it is recommended that operators discuss with an oil

company's local representative, the lubricants best suited to the particular climatic conditions under which

the equipment will operate.

4. TIGHTNESS OF BOLTS SCREWS AND NUTS

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

It is essential that all bolts, screws and nuts are kept tight, because any loosening can cause failure of the

vehicle as well as damage to adjacent or associated apparatus. There is also the possibility of fire being

caused by arcing at loose terminals.

Suitable locking devices are provided in the form of high grade spring locking-washers, locking plates,

grub screws or prick-punching etc., and when dismantling take place these locking devices must be

replaced by devices of the same grade of material and in the same form as originally supplied.

Contactor contacts, which are subjected to repeated impacts, connections, which are subjected to severe

heating cycles such as those, associated with resistors, and the smaller sizes of cable terminals, are items

which are most liable to loosen.

Before the equipment enters service, carefully check every electrical connection and contact. Repeat this

check after a week and then every three months for the first twelve month's operation. If at the end of

twelve months, no further loosening is detected, it can be assumed that all connections will maintain their

tightness for an indefinite period and the checking may be discontinued.

The reason why certain contacts and connections become loose is due to the copper deforming slightly

when under pressure, and the repeated tightening causes it to become compacted and work hardened.

5. ELECTRICAL INSULATION

Insulation can fail either by puncture through the body to the material, or by surface breakdown.

Puncture depends upon the quality and thickness of the material and the voltage across it. It follows,

therefore, that if insulating material has suffered damage, it must only be replaced by material of the

original thickness and quality.

Surface breakdown depends upon the quality of the surface of the material, its cleanliness and freedom

from moisture, the surface length, and the voltage across it.

If the surface is contaminated by dirt and/or moisture it becomes slightly conducting and a minute current

will flow along a very narrow track. This current will produce heat along the track, which may cause the

dirt and/or the surface of the insulation to carbonise and the "tracking" current to increase. The action

then becomes cumulative and if the surface is not cleaned, a flashover of power current will occur sooner

or later.

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The insulation surface between two points at different voltage level is known as the "creepage distance"

while "tracking" is the term applied to the visible evidence of the passage of minute currents along

irregular tracks on the insulation surface.

The top surface of horizontal insulation is, of course, mere prone to contamination by dirt and moisture

and requires more frequent cleaning than vertical surfaces.

When an insulation surface becomes damaged by tracking or has deteriorated with age, it can be

reconditioned by painting it with good anti-tracking enamel. Such as grey insulating enamel which can be

supplied by brush and which is air-drying.

When apparatus is being overhauled, take the opportunity to recondition the insulation surface, if this

appears to be necessary. If porcelain insulation suffers surface damage, fit new porcelain; however, the

surface of Mycalex insulation or resin-bonded asbestos can be reconditioned by cleaning it with fine glass

paper.

Porcelain insulators which are exposed to the weather may become encrusted with a hard surface of

carbon, copper and brake-shoe dust, etc., which is difficult to remove. By coating the surface with

Metroarc-17 or Silicone-110 grease, the contaminants may be removed easily at suitable grease intervals;

re-grease the porcelain insulators after cleaning. First, apply the grease thinly on the hands, then run the

hands lightly over the porcelain surface.

6. ARC CHUTES

The arc-chute walls, especially the area adjacent to the contact tips, will exhibit charring and soot from the

arc, and splatter from the contacts dependent on the severity and duration of the arc. Maintenance work is

rarely necessary but it is important to examine the arc chute interior for unusual charring or an unusual

extent or copper splatter on the arc horns or splatters which would indicate a fault on the Contactor or its

associated equipment.

If an arc chute is removed for inspection, always refit it in its original position so that the pattern of its

characteristic wear can continue. To achieve this, mark each arc chute to correspond with its Contactor.

When an arc chute has reached its safe limit to working life on a heavy-duty Contactor it may be

economic to extend its life by interchanging it with the chute from a lightly loaded Contactor.

Record any such interchanges so that the equipment inspectors understand the reason for wear on the

lightly loaded Contactor, the arc chute of which may normally remain almost as new.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

After fitting an arc chute and during any inspection of arc chutes, ensure that the chute is securely in

position and, PROVIDED THAT THE CONTACTOR IS NOT LIVE, manually operate the Contactor and

observe that the moving contact does not foul the chute.

Ensure that spare arc chutes are always available in the running sheds, safely stacked and kept clean and

dry, to enable any damaged or badly-eroded chute to be changed quickly.

Overhaul

Asbestos develops a skin, which would not be disturbed by rough filing. Use a fine file or glass paper to

remove loose dirt and any copper globules, which may foul the moving contact.

Since un-weathered asbestos is hygroscopic, new or freshly repaired arc chutes should be kept warm and

dry. Wet arc chutes can cause low readings of insulation resistance on the power circuits.

Mycalex is not hygroscopic and the surface can be reconditioned by rough filing, if necessary.

Examine the arc chute mounting arrangement. Recondition Starting threads on mounting blocks and

screws.

Examine the arc-chute interior for signs of rubbing or transferred paint due to fouling by the piston

insulator or the blow cut coil.

Erosion in the form of creators in the side plates, and gutters in the top and bottom spreaders can often be

repaired with an arc-resisting cement provided that the erosion has not penetrated too deeply. Clean

thoroughly with glass paper the part to be cemented. The cement can then be applied with a knife and the

repair dried in an oven or air dried before the chute is used again.

Scrape any soot from the joints between side plates, splitters and spreaders and look for penetration by the

arc in to the joint. Fill any such penetration with arc-resisting cement. Use this cement to coat the joints

during re-assembly of any arc chute components, which are prone to severe penetration.

Ensure that any copper inserts in the arc-chute body are securely fixed.

Ensure that incorrect re-assembly does not allow the arc to strike any fixings, especially which pass

through the arc chute.

7. ARCING HORNS

Contactors with un-swept top arcing horns depend upon a good fit between the horn and the chute to

produce a gas proof joint for the protection of the blow-out coil; this close fit must be preserved when a

new arc chute or horn is fitted. This fit should be equivalent to a clearance not greater than 0.25 mm

between horn and chute.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

When arcing horns become badly eroded at their tips and become appreciably shortened, fit new horns.

When unswept top arcing-horns become eroded to half their original thickness, fit new horns.

8. CONTACTS

Copper and silver are in general use as contact materials. Although the resistance values are similar, silver

is an inferior arcing material due to its rapid erosion and is used only for low-voltage control-circuits with

light arcing duty and for heavy-current contacts with no arcing duty.

Silver forms on its surface a low-resistance sulphide, which is brown to black in colour, and need not be

disturbed.

Copper forms an oxide, dark in colour, which has a high resistance. This would cause overheating if it

were left on a contact face.

For Contactors (which interrupt current frequently as distinct from a switch or an isolator) copper is used.

Each contact is formed in the shape of a foot with a distinct heel and toe and the moving contact is spring-

mounted on a pivot. As the Contactor closes, initial contact is made at the toes of the contacts and, as

closure proceeds, the moving contact rolls and slides over the fixed contact until final contact is made at

the heels. The action is reversed when the Contactor opens; the area of contact travels to the toes where

the contacts separate, so that the arcing when current is broken has its roots at the toes of the contacts. By

this means, the transfer of current can take place across well-mated surfaces free from arcing. The action

of the moving contact is termed KNUCKLING and is a combined rolling-and-sliding motion.

Copper contacts for light-duty contactors and for switches do not always have a distinct toe and heel with

a knuckling action, but they are always given a sliding action or WIPE, which promotes a self cleaning

action of any copper oxide that may have formed.

In general, silver contacts close with a simple butting action and such contacts are termed BUTT contacts.

The term OVER-TRAVEL is used for both wiped and butt contacts with reference to some particular

point on the moving contact or its carrier and denotes the distance that this point would travel after making

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

initial contact if the fixed contact were then removed. It is therefore an indication of the amount the

contacts can wear before effective contact fails.

In some applications, a Contactor may combine the properties of copper and silver by having a pair of

copper contacts with silver inserts at the current-carrying areas. On other contactors, separate pairs of

contacts in parallel are used, one pair of copper and one pair of silver, with the silver, contacts closed only

in the fully-closed position of the contractor and the copper contacts making and breaking the current.

DO NOT USE EMERY OR GLASS PAPER to clean contacts, as particles of these materials, which

might adhere to the surfaces, would cause faulty contacts.

DO NOT USE WIRE WOOL to clean contacts or any other electrical apparatus.

When contact tips are being fitted, tighten them lightly, and then finally tighten them with the Contactor

energised or firmly held in its closed position. This will give the best possible bedding of the contacts.

Some contact carriers have a ledge on which the contact locates, so that no movement can take place

during the repeated closing of the Contactor and such contacts must be seated fully with the fixing screw

and tightened before finally tightening with the Contactor fully closed.

On a rebuilt Contactor, the fixed-contact holder may be askew, thus preventing good bedding of the

contacts. Correct the contact holder by slackening its fixings, then tightening with the Contactor closed.

If the contact tips are discoloured by overheating, examine them for dirt or a coating of copper oxide on

both the front and rear conducting surfaces; check also the tightness and bedding of the contacts with each

other and with their holders. Overheating may also be caused by low contact-pressure due to worn

contacts, lack of overtravel, or a weak knuckling-spring.

Examine knuckling or contact springs periodically to ensure that no stiffness has developed in the hinge,

and that the spring has not weakened. An experienced inspector will quickly discover any abnormality of

the hinge or the spring pressure by manipulating the device.

Fit new contacts in place, if any, which have worn to half their original thickness of copper or silver.

Always fit new contacts in pairs since it is not practical to bed a new contact with a worn one. Except on

small contactors and auxiliary contacts hand filing of badly worn contacts to produce a true surface

capable of being correctly mated, is a highly-skilled operation and is rarely successful. If it is attempted,

the filing should be carried out with the contacts in a vice so that pivots or pistons are not stressed, and no

metal particles fall on the apparatus.

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Transference of metal from one contact to the other occasionally occurs in inductive circuits. When this

occurs, file the contacts to their normal contour in a vice, or if the transference is appreciable, fit new

contacts.

Restrict filing in position to a fine file to remove copper oxide and small high spots on current-carrying

surfaces, also to remove copper beads from contact edges and arc-rupturing areas, since these may foul the

arc chute or may eventually drop into the moving parts of the contactor.

Copper contacts

After a few weeks in service, the appearance of the contacts will indicate where the interruption is taking

place by a rough copper surface and where current carrying takes place by bright copper areas. A dull

surface indicates where the contacts are not mating; such a surface on the heel of a contact would indicate

that the knuckling action is incomplete or that the contacts are misaligned.

A regular inspector will appreciate the condition to be expected from the contacts. Since each pair will

develop contact wear and copper splatter on the arc horns and arc chutes characteristic of its position in

the circuit. As a guide to the amount of wear to expect, the inspector should at first learn whether each

pair of contacts breaks or makes current or both or is simply used for isolation. Note that the contact wear

on some contactors with light duty or infrequent heavy duty under fault conditions, may be largely due to

mechanical hammering and knuckling. The inspector should be able to recognise unusual wear, which

may indicate a fault on the contactor or on its associated equipment.

Current-carrying areas which have a bright appearance, but which have become rough and pitted, indicate

good contact and need not be disturbed.

Silver Contacts

In normal operation only a visual inspection is necessary between overhauls.

On control circuits with inductance, arcing will cause a transfer of metal, but the resulting pip and trough

will not normally warrant attention until the overhaul stage. When appreciable erosion has occurred,

smooth the surfaces with a fine file and readjust the contact gap and overtravel.

The contact pressure of control and auxiliary contacts are not critical, but it is necessary to ensure that they

have adequate overtravel, so that they will be effective even after some wear has taken place.

On power circuits, there will be no arcing unless there is fault condition.

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CONTROL GEAR EQUIPMENT

9. PNEUMATIC PISTONS AND CYLINDERS

9.1 Lubrication

Lubricate the cylinders and piston rods of E.P. Contactors periodically with grade SAE 30 oil, otherwise

their operation will become sluggish, and this will be detrimental to the general operation of the

equipment, particularly to rupture the arc. Lack of lubricant will also cause rapid wear of the cylinder

wall, piston rod and guide.

In order to lubricate the piston rod of an E.P. Contactor, raise the piston in its cylinder (by pressing the

magnet valve button) and add a small quantity of oil to the countersink which surrounds the rod at the top

of the cylinder to lubricate the cylinder, inject a small quantity of oil through the special oil-hole in the

cylinder wall.

E.P.Contactors with horizontally disposed cylinders do not require the piston rod to be lubricated, because

the rod passes through a clearance hole in the end of the cylinder.

Lubricate the cylinders of reversing switches and change over switches with grade SAE 30 oil, through

nipples provided in the cylinder walls. Before adding the lubricant , ensure that the piston is coincident

with its nipple. When one piston has been lubricated, move the piston assembly to the other end of its

stroke (by pressing the relevant magnet-valve button).

Before refitting a piston in to its cylinder, smear the cylinder wall thoroughly with oil.

Lubricate the rack, pinions and levers of reversing switches and changeover switches with Shell Alvania 3

or 4x grease.

9.2 Dismantling and assembling

Cylinder walls have a very fine and smooth finish to avoid wearing out the rubber piston seal. Great care

must be taken, therefore, to ensure that the surface is not damaged.

When dismantling the pistons of pneumatic contactors, it should be borne in mind that the return spring is

under compression. When the nut holding the piston to the rod is released, it will tend to fly out of the

cylinder and might be damaged or cause damage to neighbouring apparatus or injury to personnel.

MAINTENANCE MANUAL FOR DETC-US

CONTROL GEAR EQUIPMENT

Carefully examine rubber seals at over haul; fit new seals if appreciable wear is evident. Seals are slightly

elastic and must be stretched and forced over the lip on the piston in to the groove.

When fitting a piston rod, anneal the copper washer seal in order to ensure an airtight joint, when refitting

a cylinder cover, use a new jointing gasket because the existing gasket is invariably damaged during the

removal of the cover, and pieces of the old gasket adhere to the cylinder and cover. Ensure that all traces

of the old gasket are removed before fitting the new gasket.

Pneumatic cylinders for contactors are sometimes provided with a loose tube on the piston rod which acts

as a piston stop to protect the return spring against over-compression. During re-assembly work, this tube

must not be omitted.

10. RESISTORS

• The following types of resistor are most commonly used on traction equipment

• Expanded metal or metal strip wound on edge

• Wire wound, mica insulated metal tubes

• Vitreous enamelled, wire wound, porcelain tubes

• Flat, wire or metal tape wound mica elements

Maintenance

• Check that all nuts, bolts and screws are tight.

• Ensure that all connections, tapping and terminals are secure and in good condition.

• Inspect resistors for damage and overheating; if necessary fit new units.

• Examine insulators and supports, remove cracked or chipped insulators and fit new ones.

• Wipe insulators with clean, dry cloth-Blow-out resistor banks with dry compressed air.

Overhaul

• Repeat maintenance.

MAINTENANCE MANUAL FOR DETC-US

8 WHEELER DIESEL ELECRIC TOWER CAR WITH UNDERSLUNG TRANSMISSION. OPERATING & MAINTENANCE MANUAL (2019) - page 4