OP
ajay123
Thank you for your reply and your answer sounds very convincing, however, the generator can generate more power then what the motor input is, so how do you resolve this, also sorry for the late response too.Ask and Ye shall receive.
This system you propose is functionally identical to all your previous ideas involving generators and flywheels, just with the extra step of water in pipes.
Say you run your pump off the mains, and in doing so put 1000kWh of movement energy into the water. That's your starting energy budget. As the water flows through the pipes, the friction against the walls and turbulence in the water will cause some loss of energy, which will escape as noise and heat. You're a talented engineer and you've made a very efficient system, so you only lose 1kWh (99.9% efficiency) at this stage. Your energy budget is now 999kWh.
So now your water is flowing through your generating turbine, and making electricity. Turbines operate with a High Pressure/Hot and Low Pressure/Cold side, extracting energy from the working fluid as it slows/cools down. The bigger the difference, the better the efficiency of the turbine. As the turbine spins, you'll again have some losses in friction in the bearings, vibration, magnetic leakage in the coils, whatever. Again, talented engineer, massively efficient system, only 1kWh of losses. You've now made 998kWh worth of electricity.
Stage three, your electricity now drives the pump, which is now disconnected from the mains since you need this to be a self sustaining system, or all you're doing is running a pump from the mains to push water in a loop. Some losses in the wires as heat, and in the motor and pump themselves as friction, noise, etc. Yet again, talented engineer, efficient system, only 1kWh of losses. You've imparted 997kWh of energy to the water loop.
You are now back at your starting point, except instead of 1000kWh of mechanical energy in the form of high pressure water, you only have 997kWh. Each time the cycle repeats you will lose some of your energy budget to heat and other forms of useless energy. After 30 (actually much less than 30) cycles your energy budget will be 1kWh and your pump won't even turn as there's not enough power to overcome inertia.
Sorry for the long reply, but we really do need you to get the point. Many, many very clever people have tried many, many different ways to extract more energy from a system than they put in. None of them worked. All power systems rely on taking a high energy density source (chemical, nuclear, or other) and spreading it out to low density heat, pinching some of the energy as it goes past to do useful things.