Transmission cross arm
A cross arm is provided, for use in a support structure for conductors within an electrical grid. The cross arm is made of weather resistant glass fiber reinforced two component polyurethane based polymers and has a “C” cross sectional shape typically arranged in a double configuration. Pairs of the cross arms are attached to utility poles in a parallel position on opposite sides of the utility pole to meet predefined design conditions. Alternatively, a single cross arm may be attached to a utility pole.
1. A structure for supporting a conductor, the structure comprising:
a transmission class structural cross arm comprising: a pultruded glass fibre reinforced polymer composite C-channel comprising a two-component polyurethane resin and layers of continuous filament mat, unidirectional roving and triax fabric, a mat orientation of the continuous filament mat being one of: longitudinal, transverse and ±45 degrees, glass of the pultruded glass fibre reinforced polymer composite C-channel being E-glass to electrically insulate the transmission class structural cross arm and a volume fraction ratio of the E-glass to the two-component polyurethane resin of the pultruded glass fibre reinforced polymer composite C-channel being between 50 and 58 to between 50 and 42; and
UV inhibitors incorporated into the two-component polyurethane resin of the pultruded glass fibre reinforced polymer composite C-channel;
wherein the transmission class structural cross arm is sized to fit into an existing electrical power transmission grid and the continuous filament mat comprises 1.5 oz/ft 2 internal layers and 2.0 oz/ft 2 surface layers with polyester veil stitched.
2. The structure of claim 1 , wherein the unidirectional roving is 56-yield with approximately 608 total ends.
3. The structure of claim 1 , wherein the two-component polyurethane resin is colored.
4. The structure of claim 1 , wherein the unidirectional roving layers are provided in a longitudinal direction relative to a length of the transmission class structural cross arm.
5. The structure of claim 1 , wherein the unidirectional roving layers are provided in a transverse direction relative to a length of the transmission class structural cross arm.
6. The structure of claim 1 , wherein the pultruded glass fibre reinforced polymer composite C-channel comprises fire retardant additives.
7. The structure of claim 1 , wherein the pultruded glass fibre reinforced polymer composite C-channel comprises a polyester veil coating.
8. The structure of claim 7 , wherein UV inhibitors are incorporated into the polyester veil coating of the pultruded glass fibre reinforced polymer composite C-channel.
9. The structure of claim 1 , wherein the pultruded glass fibre reinforced polymer composite C-channel comprises a volume fraction ratio of E-glass to resin of approximately 53 to 47.
10. The structure of claim 3 , wherein a color of the two-component polyurethane resin-matches a color of a utility pole.
11. A structure for supporting a conductor, the structure comprising:
a transmission class structural cross arm comprising: a pultruded glass fibre reinforced polymer composite C-channel comprising a two-component polyurethane resin and layers of continuous filament mat, unidirectional roving and triax fabric, a mat orientation of the continuous filament mat being one of: longitudinal, transverse and ±45 degrees, glass of the pultruded glass fibre reinforced polymer composite C-channel being E-glass to electrically insulate the transmission class structural cross arm and a volume fraction ratio of the E-glass to the two-component polyurethane resin of the pultruded glass fibre reinforced polymer composite C-channel being between 50 and 58 to between 50 and 42; and
UV inhibitors incorporated into the two-component polyurethane resin of the pultruded glass fibre reinforced polymer composite C-channel;
wherein the transmission class structural cross arm is sized to fit into an existing electrical power transmission grid and the triax fabric is E-TTXM4008-10 triax fabric comprising 12 oz/yd 2 in each ±45°, 16 oz/yd 2 in 90° and 6.75 oz/yd 2 chopped mat.
12. The structure of claim 11 , wherein the unidirectional roving is 56-yield with approximately 608 total ends.
13. The structure of claim 11 , wherein the two-component polyurethane resin is colored.
14. The structure of claim 11 , wherein the unidirectional roving layers are provided in a longitudinal direction relative to a length of the transmission class structural cross arm.
15. The structure of claim 11 , wherein the unidirectional roving layers are provided in a transverse direction relative to a length of the transmission class structural cross arm.
16. The structure of claim 11 , wherein the pultruded glass fibre reinforced polymer composite C-channel comprises fire retardant additives.
17. The structure of claim 11 , wherein the pultruded glass fibre reinforced polymer composite C-channel comprises a polyester veil coating.
18. The structure of claim 17 , wherein UV inhibitors are incorporated into the polyester veil coating of the pultruded glass fibre reinforced polymer composite C-channel.
19. The structure of claim 11 , wherein the pultruded glass fibre reinforced polymer composite C-channel comprises a volume fraction ratio of E-glass to resin of approximately 53 to 47.
20. The structure of claim 13 , wherein a color of the two-component polyurethane resin matches a color of a utility pole.