Vol. 10  No 4 August  2002

Integration Components

Hermetically Sealed Relay TO-5

Hermetically sealed relays are electromagnetic relays housed in a hermetically sealed enclosure for hermeticallysealed.jpg (29215 bytes)trouble-free operation of the constituent parts to perform switching operation by armature action. These relays are iDEAL for controlling the making and breaking of circuits of electrically operated equipments.

TO-5 is a hermetically sealed miniature relay with welded enclosure to perform reliably under the most severe conditions. The relay consists of a diode for coil transient suppression. The relay is iDEAL for use in missiles, aircraft, spacecraft, and ground support and electronic communication equipment and meets the electrical and environmental performance requirements of US Military Specification MIL-R-39016/15. TO-5 is manufactured by M/s  CII Guardian International Ltd, Kochi.

relay4pdt.jpg (192038 bytes) relaydpdt.jpg (290049 bytes)

Salient Features

Coil voltage rating : 28 V DC 28 V DC 26.5 V DC
Contact current rating : 10 A 5 A 1 A
Insulation resistance : 100 M W 100 M W 10,000 M W
Operate time : 10 ms 6 ms 2 ms
Release time : 10 ms 6 ms 4 ms
Life : 1,00,000 c/s 1,00,000 c/s 1,00,000 c/s
Temperature : MIL-R-6106/28 MIL-R-6106/28 MIL-R-6106/28
Contact resistance : - - 0.1 W (max)

Heat Shrinkable Boot-Silverline

Silverline heat shrink boots are molded parts with a silver coated copper wire mesh covering Heat Shrinkable Boot-Silverlinethe inner side of boot. These boots shrink on application of predetermined amount of heat to take up a definite shape. When boots are shrunk, the wires of the mesh get closer by providing strain relief at the cable outlet of the multiway connectors. The shrink ratio of the boot is 2:1. The boots are noncorrosive with high degree of resistance to chemicals, solvents, oils, lubricants and fungus. Silverline boots are available in two different sizes, 12 and 16. The boots are intended for constructing robust multiconductor cable connector assemblies. They not only provide strain relief at the cable outlet of the multicontact connector but also protect connector cable assembly from EMI. They seal cable harness from atmospheric and other contaminants that would affect the performance of the joints. The boots are manufactured by M/s REPL Engineering Ltd, Mumbai.

Salient Features

Size 12 Size 16
Diameter of the boot as supplied : 28 52
Tensile strength : 13.59 N/mm2 13 N/mm2
Elongation : 350 per cent 350 per cent
Water absorption : 0.3 percent 0.3 percent
Tensile strength : 11 .88 N/mm2 17 N/mm2
Elongation (Thermal aging) : 300 per cent 450 per cent
Dielectric strength : 10 kV (min) 10 kV (min)
Volume resistivity : 1 x 1012 W/cm 1 x 1012  W/cm
Flameability : Non-flammable Non-flammable
Specific gravity : 1.4 1.4
Insulation resistance 8 X 105WM 8 X 105MW

Two- & Three- Electrode Spark Gaps

twoelectrode.jpg (122270 bytes)Spark gap is a unique gas filled high-energy switch able to change quickly from high impedance state to a low impedance state in response to terminal voltage applied across electrodes. The gap is an excellent insulator until the voltage across it reaches a critical value. At or above this critical value, an arc is rapidly established, which is able to carry a large current with small voltage drop.

Spark gaps are used as protective devices against voltage surges, lightning protection, 3electrode.jpg (74294 bytes)magnetrons, single pulse generators, pulsed laser switches and find applications in high voltage and high current switching circuits. The special features of these spark gaps are consistent breakdown voltage and high current capability. These spark gaps are manufactured by M/s Zeonics, Bangalore.

Salient Features

2-electrode 3-electrode
Capacitance : 5 pF 5 pF
Breakdown voltage : 15 kV  10 per cent 60 kV 10 per cent
Peak current : 3 kA (max) 5 kA (max)
Discharge DC arc voltage : 100 V 20 to 30 kV pulse
Temperature : -40oC to 85oC 300 V typical (500 V max)
Trigger voltage : - 20-30 kV pulse

Light & Heavy Tow Cables

lowtowcable.jpg (88807 bytes)Tow cable is a special type of electromechanical cable designed for underwater applications. This composite cable intended for towing operation of SONAR systems, provides electrical and mechanical link to these systems. Light tow cable has satisfactorily met the requirements of 10,000 cycles of flexural strength test at 750 kg, low temperature test at -40C for four hour and thermal cycling test of 2 cycles between -20C and +80C.

Heavy tow cable is surrounded by a polyurethane sheath (outer sheath) andheavytowcable.jpg (207553 bytes)armoured with stainless steel wire of 1.85 mm dia. This cable has met the requirements of 10,000 cycles of flexural strength test around a pulley of diameter equivalent to the minimum-bending diameter, i.e., 900 mm with a constant load of 1000 kg. These tow cables are manufactured by M/s Uniflex Cables Ltd., Umbergoan, Gujarat and M/s NICCO Corporation Ltd, West Bengal.



Salient Features

Light tow cable Heavy tow cable
Signal lines Power lines Signal lines Power lines
Conductor resistance (max) 208 W/km 30 W/km 220 W/km 16 W/km
Voltage rating 100 V 1000 V - 1000 V (min)
Capacitance 100 pF/km (max) 100 pF/km (max) 120 nF/km (max) 120 nF/km at 800 Hz
Cross talk suppression (min) 80 dB 80 dB 80 dB -

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