Please let me know 2 inch water in borewell means how much litres per hour or litres per minute. What is the logic or what is background explanation in converting INCHES of water into litres/hour?

My second question is: how much a 7.5 HP submersible pump can pump/hour at head of 320 Feet with 12 Stages. I am posting this query as in our borewell the 7.5 HP pump stops every 30 secs after pumping for 15 secs. These 15 secs water comes full in 2 inches pipe, later it gives break of 30 secs and then starts pumping for 15 secs. I was thinking, as per the  pump chart, 7.5 HP motor with 12 Stage pump can deliver 6500 Litres/Hour at a depth of 320 Feet, so my borewell acquifer capacity is only 3000 Litres/Hour, so that the pump in our borewell is pumping only for 15 secs and then stopping for 30 secs. Is this right, kindly advice. 

Regards,

Mahesh Rao