This is a case of a miss use of a low voltage generator
- gpm = 7.56 l/s
- feet = 7.6 meter
watts = 7.56 * 7.6 * 6 ( g* efficiency)= 344 watts
Generate around 120 volts AC and use 3 transformers to bring the voltage down as needed.
Losses can be reduced to about 5 - 7 % from generator to diodes output.
Use a Turgo turbine attached directly to a generator like an ECM motor as a generator ( 1 HP ).
Water velocity = sqroot( 2 * 7.6 * 9.81) = 12,2 meter/sec
Turbine peripheral speed = 6.1 m/s
For a 100 mm turbine
6.1/(pi* diameter) 6.1/(3.14 * 0.1) = 19.4 RPS
RPM = 19.4 * 60 = 1160
EVEN A 110 MM turbine will do !!
Easy to start and maintain, also logical for distance transmission with low losses.
The cost of the magnets may be higher than the cost of the ECM in Ebay, and you have the generator well built and the Turgo from www.h-hydro.com .
If you need further assistance email direct to me. I have done many hydros.
Nando