The gear unit consists of Four to Five reduction stages comprising of bevel, helical and planetary being a last pair in the system. The gear units are available in hollow shaft design with Shrink Disc and have a integral drive frame for mounting electric motor and brake, with necessary fork for fixing the torque arm. The sun, planet and helical wheels are case hardened and ground to quality 6 as per DIN 3961-63. The annulus is made up of high tensile alloy steel, heat treated or nitrided depending upon power requirement. The spiral bevel gears having cyclopalloid tooth from are case hardened and lapped in pairs so as to ensure optimum tooth contact pattern during assembly. The casing is of welded construction mainly in two parts made out of Fe 410 WA IS 2062. The bearing bores are machined with high degree of accuracy on CNC machines.