Hi Zeke, If you calculate the relative power per wattage of single and three-phase motors, there will be a slight advantage to 3-phase. The value of 3-phase motors also extends to their better torque and start-load characteristics and lack of starting capacitor(s) to maintain. I would base my system on availability and overall usefulness rather than those relatively modest advantages of 3-phase motors. A single-phase, dual voltage (as in 240 / 120 volt in the USA) setup allows use of higher voltage for motors and the lower voltage for appliances and lighting. Single-phase inverters are the norm for converting stored Direct Current energy to useful Alternating Current power. You're on the right track to run your generator while running your motors. If you have inverters, they can augment the output of your generator to help with start-loads (up to 5 times the run-load of the motor). The battery bank can be charged by the excess generator power and by photovoltaic, wind, etc. at all times. In capturing generator heat, don't forget the waste heat of the exhust stream, harder to capture than the coolant heat, but about equal to it in power. Good luck with your project.
Tom Thiel On 2 Jan, 2008, at 7:19 PM, Zeke Yewdall wrote: > Are the three phase motors really more efficient? Or are they just > lower amperage, but the same wattage? The formula for calculating > three phase power, instead of being V*A*PF is V(line to > line)*A*1.732*PF, I believe. > > Z > > On Jan 2, 2008 5:11 PM, <[EMAIL PROTECTED]> wrote: >> >> -------------- Original message ---------------------- >> i want to set up a small diesel generator to run my milking parlor >> and use the engine heat to supply the hot water. Since the pumps and >> refrigeration are my biggest load, but are only on for a few hours a >> day, i was thinking a 3 phase generator would be better because the >> motors operate at about half the amperage and would reduce the size >> of the generator i need to run. I was thinking a 6/1 or a 12/2 lister >> diesel. the fuel consumption on these is about 2 liters per hour. I >> only need to run about 2 -1 hp motors and 1- 2hp for milking and >> cooling ,then i could run the generator to charge batteries for the >> house and help heat the house in the winter. Any suggestions? it just >> seems to easy to change out the motors to 3 phase and reduce the kw >> size of my generator. >> >> _______________________________________________ >> Biofuel mailing list >> Biofuel@sustainablelists.org >> http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel >> >> Biofuel at Journey to Forever: >> http://journeytoforever.org/biofuel.html >> >> Search the combined Biofuel and Biofuels-biz list archives (70,000 >> messages): >> http://www.mail-archive.com/biofuel@sustainablelists.org/ >> > > _______________________________________________ > Biofuel mailing list > Biofuel@sustainablelists.org > http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Search the combined Biofuel and Biofuels-biz list archives (70,000 > messages): > http://www.mail-archive.com/biofuel@sustainablelists.org/ > _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (70,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
