Looking into “reverse engineering” a pump and running it like a turbine and using an induction motor of some sort generate power. Basically design/build my own micro-hydro power system. The system if I do go ahead with it, will be connected to the grid. I am very capable of handling the mechanical side of things, however I have a lot of reading to do when it comes to the electrical side. From what I have read so far I need an asynchronous generator (or induction motor). I will list my questions, it makes it much easier to read: 1. From what I have read, I understand if the induction motor spins above the rated motor speed it becomes a generator, anything below the motors rated speed and it becomes a motor. Is this correct? 2. Suppose the motors rated speed is 1500rpm, and I design my turbine to spin at 1600rpm and connected it to the motor, will it begin to generate power and automatically synchronise to the gird? What happens if there is a sudden increase in flow rate and the turbine spins up to 1950rpm what would happen to the generator, would it continue to produce power and synchronise to the grid? Is there a maximum speed the generator can handle? I know for a synchronous generator I can use that formula to calculate synchronous speed (depends on number of poles and grid frequency), is there a certain percentage of this that should not be exceeded by an asynchronous generator for example the turbine speed should not go higher than 10% of the synchronous speed? 3. What happens if the generator is happily generating and is suddenly cut off from the grid? For example it is turning at 1600rpm and then suddenly it is disconnected from the grid, it is turning too fast to be a motor. Or if there is a spike or instability in the grid? 4. I was told to look into a doubly-fed induction generator, (DFIG). Would a DFIG system suite my application? I have tried searching for DFIG manufacturers and couldn’t find anything, are there any companies that sell complete DFIG units? Are prices substantially more expensive than that of an asynchronous generator? Thanks for any help in advance, I understand I have a lot of reading to do!