1)The Impulse Turbine consists of one set of Nozzle followed by one set of moving blades 
as shown in above figure. 

 2)In Impulse turbine power is developed by impulsive force of high velocity steam jet on 
moving blade.

 3)Steam from boiler enters in nozzle ring of impulse turbine where, high velocity jet is
obtained by expansion of steam in nozzle ring.

 4)Moving blades changes direction of steam jet thus the momentum of jet which rotates
the shaft.

4)High velocity steam jet then passed through moving blade ring with no pressure drop
but gradual reduction in velocity.