An outward radial - flow impulse turbine has nozzles with a total effective area of 970mm² and the guide vanes make an angel of 20 degree to the tangent at exit. The inner and outer diameter of the runner are 508mm and 712mm respectively, and the moving vanes have an outlet angle making 20 degree to the tangent. When running at 620rev/min under a head of 61m the discharge is 1.8m cube/min and the power outlet is 11.9kw . The water is observed to leave the runner in a forward direction and inclined at 15 degree to the radius. Assuming the water leaves tangentially to the moving vanes, calculate the head lost in
a) the nozzles
b) the moving vanes
c) bearing friction and windage .
A series generator is operating in the linear region where the flux is directly proportional to the armature current. The armature resistance is 80 mΩ, and the series field-winding resistance is 20 mΩ. At a speed of 1200 rpm, the terminal voltage is 75 V and the armature current is 20 A. What must be the armature current for a terminal voltage of 120 V at 1200 rpm? If it is required to have a terminal voltage of 100 V at an armature current of 25 A, what must be the armature speed?