MINIATURE HIGH VOLTAGE
WIRES AND CABLES
WHAT IS TWS?
ADVANTAGES OF TWS
SPECIAL EQUIPMENT WIRES
ADVANTAGES OF TWS
LIST OF MIL-W SPEC SHEETS
CONDUCTOR SIZE TABLE
INSULATED WIRE SIZES
COAXIAL CABLES PER MIL-C-17
TABLE OF COAXIAL CABLES
HIGH VOLTAGE WIRES & CABLES
HVCR SELECTION GUIDELINES
HVCR QUALITY ASSURANCE
HVCR SIZE TABLE
WIRES FOR FLOOR HEATING
QUESTIONNAIRE FOR HVCR
Previous page -- Selection Guidelines, Product Range
PERFORMANCE & QUALITY ASSURANCE
The curves of performance in Figure below show accumulated experience of 30 years. At about 5 KV AC working, the Break Down Voltage (BDV) is 30 KV AC, and 80 KV AC at 20 KV AC working. The Progressive Stress Test (PST, described here) simulates more closely the influence of corona on cable life. It is a type of accelerated life-test under corona attack. The observed co-relation between life of a cable under long-time tests at actual working voltages and under PST provides safe, repeatable prediction of cable life based on PST data.
HVCR cables generally have problems with `Strip-Force' (adhesion of conductor to insulation) especially for higher insulation thickness; either the conductor is free-moving inside the insulation, or the it is difficult to remove from the conductor. Our R&D has solved this important technical problem. Now smaller conductor size with larger X CR rating is available with good adhesion of conductor and good strip force.
The test procedure and specs for HVCR cables are briefly described here. There are no generally accepted specifications for HVCR wires & cables. The test methods described here are based on long experience and specifications are proprietary.
On 100% length, 15 minute water soak, and water tank tests:
(a) Dielectric Test at Working Voltage (WV) + 10% + 1 KV; duration 5 minutes (e.g. for WV 10 KV AC/22.5 KV DC, test will be at 12 KV AC).On samples, Progressive Stress Test (PST) on 0.6 metre samples from both ends of each piece (and identified):
(d) On these samples, AC voltage is applied in water tank test, starting at 1 KV and step-increasing by 2 KV at the end of each minute until break-down. Time and voltage are noted, and the range/spread recorded. BD Time should be above the minimum specified in the Figure for each piece. Average of all values should be well above the minimum specified.
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