Neutral Sections are provided to isolate different phases of power supply in adjoining OHE fed by

adjacent substations, which are normally connected to different phases of supply.

Short Neutral Section Assembly PTFE Type.

• Short neutral section is light weight contact wire insulator of composite type (Resin bonded glass fiber core protected with wear resistance ceramic beads) with Poly Tetra Fluro Ethylene, known as PTFE as shown in figure 1. These should be as per RDSO,s drg. No.

(i) ETI/OHE/SK/551- Arrangement of neutral section for conversion with short neutral section.

(ii) ETI/OHE/SK/552- Arrangement of short neutral section at existing feeding post.

• Speed of trains under such neutral section assembly is 200 kmph.

• This assembly has advantages of ease of installation even on flat curved locations and substantially reduced maintenance.

• The lengths of PTFE type neutral sections are 9.0 m, 5.0 m and 3.736 m.

Locations

NS

400 m 200 m

i. PTFE type short neutral section is erected on level tangent track, flat curves and difficult locations.

ii. The stagger of short neutral section is zero at support.

iii. The PTFE type short neutral section is located on track at a distance of at least 400 meter, after the stop signal and 200 meter before the stop signal as shown in figure below.

Maintenance

1 a. Check any cracks on anti- torsion tube to messenger clamp.

b. Check free movement of telescopic anti-torsion tube.

2 a. Check earthing lug for any flash mark and loose connections etc.

b. Ensure that earth wire is provided with lug.

3. a. Check ceramic beads for any crack.

b. Clean carbon deposits under ceramic beads by wiping with cotton cloth soaked in petrol.

4. Check clearances between:

a. Arcing horn and arc catcher (horizontal clearance maximum 320mm).

b. Arc catcher and ceramic bead (vertical clearance minimum 170mm).

5. Check burning of arc traps and arcing horns.

6. Check complete bracket of PTFE for any abnormality.

7. Check flash marks on structure bond connected between PTFE mast and rail.

8. Measure earth resistance twice in a year, it should be less than 10 Ohms.

2968 NOMINAL LENGTH OF INSULATING SECTION

3736 NOMINAL LENGTH OF CONTACT WIRE TO BE REMOVED

384768 INSULATOR CREEPAGE

LENGTH 1100384

1 CERAMIC BEAD INSULATOR

CONTACT WIRE CLAMPCONTACT WIRE

NORMAL DIRECTION OF TRAVEL

ANTI-TORSION 9SPRING DROPPER

12 ADJUSTABLE 'V' DROPPERS FOR LEVELLING OF ARC CATCHER

4 2 B

X

CABLE TIE

2 CONTACT WIRESPLICE

660660

100 OFFSET

11 JUMPER AT EARTH

POTENTIAL

14 SWIVEL CLIP

13 SWIVEL CLAMP

10 ARC CATCHER

ANTI-TORSION TUBE TO

MESSANGER CLAMP 8

THIS DIMENSION INDICATES SEPARATION BETWEEN

EDGES OF CLIPS

4 MESSANGER/ JUMPER CLAMP

EARTHED SUPPORT AND REGISTRATION POINT

CONNECT TO EARTHING

SYSTEM WITH COMPRESSION

LUG

G.F. MESSANGER INSULATION 6

MESSENGER STRAND 19/2.1 HARD DRAWN COPPER CADMIUM

1100

735 535

2500

340

50 50

340

900

2300

7 MESSANGER/ END

CLAMP

170 mmMax. 320mm

Safety Tips

�Ensure that power supply of elementary section of both ends of neutral section is switched off and earthed before commencing the work.

�Only after obtaining permit to work (PTW) from TPC, climb on roof of tower wagon.

� Always use industrial helmet during work at site.

Disclaimer:

It is clarified that this pamphlet does not supersede any existing provisions laid down by RDSO, Railway Board or Zonal Railways. The pamphlet is for guidance only and it is not a statutory document.

If you have any suggestion or comment, please write to:Director (Electrical), CAMTECH, Maharajpur,

Gwalior (M.P.) – 474 005Ph.0751-2470740, Fax 0751-2470841

(For Official Use Only)

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PAMPHLET

on NEUTRAL SECTION MAINTENANCE

PTFE TYPE

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CAMTECH/E/2010-11/Pamp-NSMAY 2010