Silicone rubber insulation has excellent electrical properties & high thermal resistance. It allows conductor temperature rating of 150° c for continous operation & 250° c under emergency over load. It maintains circuit continuity even in fire because silicon rubber burns into an insulating ash. It is resistant to moisture, ozone radiation & chemical. Being elastomeric in nature it is flexible & flexibility is retained over wide range of temperature (+150° c to -55° c).
GENERAL APPLICATIONS
High temperature operation
Good electrical properties
Moisture abrasion resistant
Long service life
Light weight
Flexibility over wide range of temperature
High thermal conductivity
Resistance to ozone & sunlight
Boilers
Steel mills
Machine tools
Electric furnaces
EOT crane
construction equipment
Coke ovens
Airport lighting or other high wattage lighting unit.
Material handling equipment
Driers
Ships (Engine room, gallery etc.
Textile machinery
Bakeries
Nuclear & Thermal power stations
Turbines
Blast furnaces
Electrical machineries of class B,F & H services
Printing presses
High furnaces generator
High temperature metallurgical plants e.g. alloy steel,cell room of aluminium
CONSTRUCTION : voltage grade, size range & specifications
1. Single core cable :- Annealed tinned copper or aluminium conductor, insulated with silicon rubber & finally fibre glass braided & varnished.
2. Multi core cable :- Cores constructed as single core cable, distinguishably colour coded & laid up circular with asbestos worming & finally glass braided & varnished or asbestos braided & compounded.
Cable with other protective sheath such as silicone, neoprene & CSP sheath, wire braid or single wire or strip armoured/screened also can be supplied.
Voltage grade : usually 1000v/3300/600/6600v
Size range : upto 630 sq mm.
Specifications : genrerally to BS:6007, BS:6500 & IS:6380/IS:9968, IEC/540
LOCO AND COACH WIRING CABLES FOR RAILWAYS
These are normally elastomeric cables & are custom built to suit invidual application in contrastwith other conventional cables, design of which is more or less standardised. The most noteworthy factor for developing elastomeric cables is in its application, where in continous vibration (as loco & coach speed on rails) are of prime importance. Cable however are simple in construction but they call for utmost care in raw material selection, process control & quality awareness. The following factor are considered when designing these cables :
1. High degree of quality & reliability during the entire span of operation. 2. Very careful selection of material due to the mechanical & environmental abuse that those cables are exposed to both during installation & in operation. 3. Utmost care in production to control & maintain within limits the dimensions of these cables. 4. Stringent quality control to ensure reliability of the product.
The prime requirement for insulation & sheath used for loco & coach wiring are as following :
INSULATION :
1. High temperature with standability 2. Good volume resistivity 3. Flexibility 4. Good mechanical strength 5. Fuel/oil resistance 6. Low water absorption 7. Low weight 8. Good electrical characteristics 9. Retention of properties at low temperature
SHEATH :
1. High mechanical strength 2. Good weather resistance 3. Good tracking resistance 4. Flexibility 5. Good oil/fuel resistance 6. High temperature with standability 7. Rentention of properties in low temperature 8. Good flame resistance
The railways have therefore opted EPR for insulation & CSP for outer sheath.
FLEXIBLE TRAILING CABLES FOR COAL MINES IS : 691-1984
S.NO
TYPE
IDENTIFICATION
VOLTAGE GRADE
APPLICATION
1.
Flexible trailing cables
FT
1.1 kv Portable m/c
coal cutters & similiar
2.
Flexible trailing cables
FTD
1.1 Kv
Hand held m/c like drill etc.
3.
Pliable armoured Flexible Cable
P3
1.1 Kv
Conveyers,Loaders & similiar transportable m/c
4.
Pliable armoured Flexible Cable
PC
1.1 Kv
Remote control circuit
5.
Pliable armoured Flexible Cable
PL
1.1 Kv
For coal face light
1.
FT
a.
FT3 - 5 Core
5 Core around a cradile separator
b.
FT4 - 5 Core
3 Power cores with protective screen one unscreened plot clad around bare central conductor.
c.
F 16 - 5 Core
Power core with protective screen with plot lad around an elastomeric centre. Cross section range : 16 to 95 sq mm.
2.
FTD
a.
FT3 - 5 Core
3 Power core + pilot + each core all 6 sq mm. laid around cradle separator.
3.
P
a.
P3 - 5 Core
3 Power core + pilot + each core around cradle separator cross section 6 to 35 sq.mm