Polar Services - Remote Station Engineering - Structural Systems

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Polar Services - Remote Station Engineering - Structural Systems This webpage is maintained with specifications for mechanical components which represent the current best-practices employed by UNAVCO in the Polar Permanent GPS Station design. Specifications are subject to change as the design evolves, however the most current design will always reside here.

TECHNICAL NOTES

Through 2007, the bulk of design work has focused on the Antarctic Margin (Coastal) Station design, which will operate in high wind environments but without the extreme cold found on the Antarctic Plateau. Components and suppliers have been selected, and an initial set of drawings has been released. This system has been fielded in quantity as part of the POLENET project in Greenland and Antarctica. In the coming year emphasis will also be placed on the Plateau design, which will operate during longer winter darkness and extreme cold, but with much milder winds. See bottom of this page for the general layout of a plateau system.

STRUCTURAL SYSTEM HARDWARE USED BY UNAVCO IN POLAR APPLICATIONS

ANTARCTIC MARGIN (COASTAL) STATION

Component	Photo	Manufacturer	Part Number (click for PDF drawing)	Description	Weight (lb)	Cube (ft^3)	Why?
Structural Frame		T & E Tech 3772 Puritan Way #9 Erie CO 80516 303-833-5330	PPS-TF-001 revE sheet1 PPS-TF-001 revE sheet2 PPS-TF-001 revE sheet3 PPS-TF-001 revE sheet4	For use on rock surfaces. Frame made of 1.5" sch40 structural aluminum pipe and slip-on aluminum pipe fittings. Accepts up to four solar panels, two wind turbines, four small or two large enclosures, and one comms antenna. Disassembles into five pieces to fit inside Bell 212 or DeHavilland Twin Otter aircraft. Further disassembly to eight pieces for shipping (e.g. Uline S-4983 box).	110	Shipping: 7 (12"x12"x84") Deploying: 9 (84"x30"x6")	Rigid, lightweight frame assembles quickly with minimal tools. Uses weight of batteries to help anchor frame. Field-proven at dozens of polar locations. Entire mechanical assembly is aluminum with zinc-plated steel hardware for corrosion resistance. No stainless to avoid thread galling.
Slip-on Pipe Fittings		Diamond Aluminum	#102-PD, #103-PD, #110-PD (all 1.5")	Used to assemble structural frame. "PD" fittings are identical to stock #102, #103, and #110 fittings except set screws have loc-tite locking patches.	Incl. in frame	Incl. in frame	Each fitting drilled and bolted thru at each pipe junction for strength (see frame drawings). Hinge fittings fully collapsible to save cargo space.
Leveling Foot		T & E Tech (contact info above)	PPS-TF-002 revA	Short sections of 1.5" aluminum pipe, cut to various lengths and drilled thru. Allows +/-1" adjustability up to 14" variations in terrain. Bundle of assorted lengths: 14"x12"x12".	Asst. bundle: 5	Asst. bundle: 1	Simple, allows frame leveling with no special parts.
Wind Turbine Mount (Forgen 500)		T & E Tech (contact info above)	PPS-TF-003 revA	Turbine stud attaches with M10x1.5 nylon locknut.	1	0.5	Stronger and more compact than stock Forgen 500 mount. Turbines attach quickly and securely to corners of frame.
Solar Panel Bracing and Backing		Bracing: T & E Tech (contact info above) Backing: Precision Design and Machine 6595 Odell Pl, Suite F Boulder CO 80301 303-527-3049	Bracing: PPS-SP-003 revB Backing: PPS-SP-004 revB	Bracing consists of aluminum angle rails bolted to top and bottom sides of Sharp NE-80EJEA panels. Backing is 12 gage aluminum sheet attached to backside of panel, for wind-hardening. Use two or three 3" wide strips of 1.5" thick blueboard foam sandwiched between backing and reverse of solar panel for added strength. Finished panel: 47.25"x24.6"x1.9".	With cable, bracing, backing: 42	With cable, bracing, backing: 1.5	Angle braces increase rigidity and allow mounting to frame. Backing (with foam) provides wind hardening, protection of panel backside from wind-blow debris abrasion. Backing also provides enclosure for excess solar cable length.
Solar Panel Cable Strain Relief Fitting		Graybar	Thomas and Betts 2921AL	Two per panel, mounted to junction box and side of panel frame. Screw fitting directly into side of solar panel frame, use with T&B 141AL locknut on junction box.	Incl. in panel	Incl. in panel	Provides excellent strain relief for solar cable.
Solar Panel Mount Saddle		DX Engineering	DXE-CAVS-3CS (Saddle + V-bolt) DXE-VBK-CAVS-3CS (V-bolt only)	Aluminum saddle with V-bolt attaches solar panels to aluminum tube frame. Same as stock part DXE-CAVS-3P except uses modified V-bolt. V-bolt is 5/16-18 thread, Grade 2 zinc-plated steel, overall length L=3.5". Also, use washers and 5/16-18 zinc-plated nylon locknuts with V-bolt.	Incl. in panel	Incl. in panel	V-shaped saddle and bolt provides better grip on piping than circular. Modified V-bolts allow use of same wrenches for frame and solar panel assembly in the field.
Enclosure		Hardigg	Small (MM36): 472-463L-MM36-CEM133 Large (MM24): 472-463L-MM24-CEM133	Insulated inner chamber formed using custom styrofoam on all sides. Small enclosure (MM36) holds electronics board plus six 100 amp-hour batteries. Large enclosure (MM24) holds electronics board plus ten 100 amp-hour batteries.	Incl. foam and connectors: Small: 55 Large: 70	Small: 14 (35"x28"x24") Large: 20 (52"x28"x24")	Rugged well-sealed "military" plastic enclosure, stackable, with large handles. Easy to handle and UV resistant. Connectors are recessed within ribs of case to reduce risk of shipping damage.
Enclosure Cradle		T & E Tech (contact info above)	Small: PPS-EN-002 revB sheet1 PPS-EN-002 revB sheet2 Large: PPS-EN-001 revB sheet1 PPS-EN-001 revB sheet2	Cradle bolts to frame with 5/16" U-bolts (McMaster-Carr P/N 3043T73). Enclosure ties down to cradle with 10 ft. cargo strap (e.g. Grainger P/N 6A265).	Small: 15 Large: 20	Small: 2.5 (35"x28"x4") Large: 3.5 (52"x28"x4")	Secures enclosures to base of structural frame.
Enclosure Foam Inserts		R&B Sales 2291 Waynoka Road, Suite B Colorado Springs CO 80915 719-596-3211	Small: PPS-EN-003 revD sheet1 PPS-EN-003 revD sheet2 Large: PPS-EN-005 revD sheet1 PPS-EN-005 revD sheet2	Assembles tightly inside enclosure without adhesive.	Incl. in enclosure	Incl. in enclosure	Creates rectangular enclosure to tightly hold batteries and provides nominal thermal insulation.
Vent Plug		Sealing Devices	W.L. Gore PMF100444	Metal shell, teflon membrane vent. Use with M10510-007 backing nut.	Incl. in enclosure	Incl. in enclosure	Allows slow equalization of internal/external pressure to relieve potential battery gases caused by battery of charging system failure, with near-hermetic seal. Standard practice for enclosures containing rechargeable batteries.