standards / manuals / guidelines for small hydro development - AHEC

Fig 14: Determining Displacements of Generator Bearings [Goncharov]• The displacement of bearings due to inclination of shaft are given by differencebetween end clearances. They depend on the location of bearings and dia of coupling‘D c ’.(a) Front bearing in horizontal plank x1 = (b 2 -b 4 ) l 1 /Dck x2 = (b 2 -b 4 ) l 2 /Dc(b) Front bearing in vertical planeK y1 = (b 1 -b 3 ) l 1 /Dck y2 = (b 1 -b 3 ) l 2 /DcCorrect position of the generator rotor can be obtained by moving its bearings byfollowing distances:(a) Front bearing – horizontal planeA x1 = (a 2 -a 4 ) / 2 + (b 2 -b 4 ) l 1 / DcA x2 = (a 2 -a 4 ) / 2 + (b 2 -b 4 ) l 1 / Dc(b) Front bearing – vertical planeA y1 = (a 1 -a 3 ) / 2 + (b 1 -b 3 ) l 1 / DcA t2 = (a 1 -a 3 ) / 2 + (b 1 -b 3 ) l 2 / Dc• The rotor must be moved up and to the right if the computed displacement is positive• The rotor must be moved down and to left if the computed displacement is negative• The air gaps of generator are checked after completing alignment. These should beequal all around the circumference• The turbine and generator half coupling are connected after completing alignment ofgenerator shaftAHEC/MNRE/SHP Standards/ E&M Works – Guidelines for Operation and Maintenance of Small Hydropower Station 72