Chakra

Inside Lord Jagannath temple, Lord Vishnu's wheel is also worshipped in the name of 'Sudarshana'. But inside the temple Sudarshana is not in the shape of a wheel, but in the shape of a small wood pillar placed to the left of image of Lord Jagannath. It is believed that the same Sudarshana is also at the top of the temple and is known by the name of Neela Chakra. 

The wheel is said to be Lord Vishnu's most powerful weapon, Sudarshana Chakra (disk). 

http://3jbs.blogspot.com/2011/12/nila-chakra-org-tv-album.html

The metal wheel at the top of Lord Jagannath temple is known as Neela Chakra (Blue Wheel). 

http://3jbs.blogspot.com/2015/02/ashtadhatu.html

It's circumferance is about 36 feet and it is so designed that there is a wheel within the wheel. The circumferance of the inner wheel is about 26 feet. Eight hubs join together the inner and the outer wheels. There are decorative designs on the outer wheel. The thickness of the Neela Chakra is 2 inches.

Weight	2200 kg
Height	11'8"
Diameter	7'6"
Thickness of Paridhi	2 inch
Width of Paridhi	9 inch
Diameter of central circle	2'6"
Number of wheel bars	8
Length of each wheel bar	1'10"

http://3jbs.blogspot.com/2015/02/garuda-sevaka.html

The Blue Wheel, at the top of 214 feet high Jagannath Temple, serves very practical purpose technically by protecting the high rise temple from thunder strokes and lighting. The eight metal alloy has the capacity to absorb the ferocity of thunder bolts and thus the gigantic stone-moment remains unharmed. There is a four-inch wide metal-plate which serves as an earthing, it connects the wheel and a well in the southern side of the temple, close to the Goddess Vimala temple. This metal plate is about 300 feet long.

Org / TV / Album

http://freedomweapon.blogspot.com/2011/12/nila-chakra-org-tv-album.html