Dear Mr. Moideen,
From the description of your problem, I understand that you have 3 phase - 10HP Submersible Pumpset and a Star Delta Starter.
I - it pumped water for 1/2 hour of 2". later it pumps on for 10 seconds full 2" and 10 seconds only one or half inch.
The borewell aquifers are all flowing sources, Initially when you are starting the Submersible Pumpset after a certain time interval the pump bails out the water column stored (STATIC WATER LEVEL) into the borewell giving you the flow of 2" for a limited time and when the water coming in from the aquifers reach at the pumping level (DRAW DOWN LEVEL) you get the reduced flow i.e. the actual incoming flow of water from the aquifers. refer figure below.
Suggested Solution to your problem -
Scenario -I with OLD PUMPSET -
If you have not installed your pumpset recently, you will need to remove the Pumpset from the borewell and get it check with your nearby dealer's workshop if the all the impellers of the Pump are functional. Now a days, there are multistage pumpsets with no.s of impellers to deliver the available water quantity from particular depth to discharge point, if some of the impellers are not functional the pump would not deliver the quantity to the fullest, and as such you will need to replace the worn out impellers with new ones.
Scenario - II With NEW SUBMERSIBLE PUMPSET -
If you have installed a newly purchased Pumpset, there is a possibility that the pumpset suggested to you by your drilling agency or the pump dealer is of the higher capacity compared to the per hour water yield available from the borewell, as such u may 1st try to return the ½" dia flow back into the borewell, by fixing a 2" x ½" dia reducer Tee SOCKET with a ball valve to divert the ½" flow back into the borewell. U may also do the Automation for the running hours of the pumpset, so that you are able get the per hour yield from the borewell to your storage tank for 24 hours (When you are SLEEPING your SYSTEM is Working)
You may try the above given suggestions & if you still have some problem, you may contact us with following informations -
- Per Hour water yield known during the drilling.
- Depth to 1st Aquifer & 2nd Aquifers from Ground Level, in the Rock formation i.e. after the installation of the Casing Pipe.
- Diameter of the Borewell.
- Type of Rig engaged for Drilling i.e. DTH, Reverse Rotary etc. and the Air compressor details.
All the above details you will get from your drilling agency.
All the Best!
YASH D SHAH