technical of ARMOUR RODS & PERFORMED FITTING
1. Ultimate Tensile Strength (UTS)
1. Though armour rods are not primary load-bearing elements, they contribute to restoring up to 90%–95% of the conductor’s original tensile strength if damaged.
2. Typical UTS Range (restorative capability):
I. 20 kN to 110 kN, depending on conductor size and number of rods.
3. Preformed dead-end grips and full-tension preforms (used in conjunction) can provide 100% of conductor UTS.
2. Working Load / Safe Working Load (SWL)
1. Since armour rods are protective, not primary tension members, SWL applies in terms of vibration damping and restored load capacity.
2. Typical SWL:
15 – 40 kN, depending on conductor type.
3. Preformed full-tension grips may have SWL = 35 – 95 kN, depending on conductor.
3. Conductor Diameter Compatibility
1. Armour rods and preformed fittings are conductor-specific.
2. Typical Compatibility Range:
6 mm to 40 mm outer diameter (covering conductors like ACSR Weasel to ACSR Zebra and beyond).
3. Precise sizing is critical to prevent strand damage or inefficient protection.
4. Slip Strength:
1. Preformed tension grips are designed to grip the conductor securely and transfer tension to the support.
2. Typical Slip Strength:
≥ 95% to 100% of conductor UTS (for preformed dead-end grips)
3. Armour rods prevent localized stress but are not designed for gripping—they work in combination with other fittings for tension handling.
5. Temperature Withstanding Capacity:
1. Materials must perform across a wide thermal range without loosening, cracking, or warping.
2. Operating Temperature Range:
I. -40°C to +120°C continuously
II. Short-term exposure up to 250°C during faults
3. The rod material (usually aluminum or galvanized steel) retains integrity even during fault current heat rise.
6. Corrosion Resistance:
1. Designed for long-term outdoor exposure, including industrial, marine, and high-pollution zones.
2. Materials:
I. Aluminium alloy rods for ACSR/AAAC conductors
II. Galvanized steel rods for earth wires
3. Surface treatment:
I. Natural oxide layer (aluminum)
II. Hot-dip galvanizing (steel rods)
III. Meets ASTM A153 / IS 2629
7. Impact & Fatigue Strength:
1. Armour rods and preforms are designed to dampen mechanical shocks and reduce fatigue caused by:
2. Can survive >10⁷ vibration cycles in coordination with Stockbridge dampers.
8. Mechanical Endurance:
1. Designed for a mechanical life of 25–30 years.
2. No cracking or unraveling under mechanical stress
3. Maintains alignment, grip, and protective function
4. Withstands environmental aging and thermal cycling
9. Design Safety Factors:
1. Tensile Strength (Preformed)**
≥ 1.5 – 2.5× of SWL
2. Slip Resistance
≥ 95% – 100% of conductor UTS
3. Vibration Endurance
≥ 10⁷ cycles
4. Thermal Safety Margin
~2× normal temperature range
Top 5 Quality Assurance
1. Standards Compliance
I. Manufactured in strict accordance with relevant standards such as:
II. Ensures reliability, conductor protection, and consistent electrical performance.
2. High-Quality Raw Materials
I. Made from high-strength aluminum alloy, galvanized steel, or aluminum-clad steel.
II. Supplied with Material Test Certificates (MTCs) for full traceability.
3.Dimensional & Profile Accuracy
I. Armour rods and preformed fittings are manufactured with precise length, pitch, and twist rate to ensure:
II. Inspected with calibrated gauges and profilometers.
4. Surface Finish & Corrosion Protection
I. Hot-dip galvanizing (for steel rods) as per IS 2629/ISO 1461.
II. Anodizing or polishing (for aluminum rods) to prevent corrosion.
III. Zinc coating thickness and adhesion are tested to ensure long-term outdoor durability.
5. Final Quality Checks & Documentation
I. Rod straightness, spring-back, and fitment on dummy conductors.
II. Matching with conductor type and size.
III. Marked with batch number, conductor range, and manufacturer’s ID.