Need solution to address the interrupted supply of water from borewell


We have dug a new bore well and got water at just 100 feet with a 1.5" yield till 400 ft, Beyond this depth the water level increased and eveyone said it is a 3" yeild. But when we inserted the motor we did not get sufficient water. The water flow was very less. Currently we have installed 30 length of steel pipe and we get water for 15min then there is a gap of 2min. Can any one explain this? Please give us a solution for this.