My 3m old son wakes up from sleep as I stop moving the cradle.For hrs I have to move it so that he gets sound sleep.What can help ?

Ur baby is already used to it by now so honestly it will be very difficult to suddenly stop. I'd suggest start using other methods such as story telling, talking or singing softly and such. Give ur baby a warm bath and a pat gently. My 2 year old started getting off this rocking habit after I introduced these alternatives. All the best.