In a fit of insomnia last night I realised that the formula I gave for sizing the hp requirement was a load of old bollocks. ie incorrect. It should read : 11000/750/.8 = about 18.5 hp required.
My apologies. JS. --- In [EMAIL PROTECTED], "indo2002nz" <[EMAIL PROTECTED]> wrote: > Hi Justin > > You will find that in 99% of cases, fixed generating powerplants > above a certain size are almost exclusively diesel powered. That > size I'm guessing now, probably around 15KVA. Diesel motors make > good usable power at 1500rpm. I suggest that you are barking up the > wrong tree so to speak looking for a petrol engine, go and find a > small diesel engine of the appropriate size and run it on > biodiesel.It needs to be rated at about 80% of the required power > output. Diesels need to work hard to be reliable. So for your > alternator you want a diesel motor hp about 11000/750 * 80% (around > 12hp I think). The 1500 rpm is significant because the frequency (Hz) > of the output alternating voltage is directly proportional to the > speed of rotation of the alternator. With most fixed AC generating > plant 1500rpm = 50Hz, that is the case with your alternator since > you mention the requirement for 1500 rpm. Diesel engines are easily > governed, I never got a grasp of the theory here but I think that > the engine speed control is a function of the fuel pump/fuel rack > function versus engine load. Someone else may be able to clarify > this for you. Certainly diesel engines are far more stable in terms > of engine speed control, reliability, and longevity for the function > that you envisage. > You can build a steel frame and direct connect the diesel flywheel > to the alternator input shaft. Take care with the alignment between > the two, it has to be very precise to avoid bearing damage in both > the engine and alternator. You make this adjustment with steel shim > stock beneath the mounting brackets. > > Motors to search for - 1 & 2 cylinder Yanmar, Lister, Buhk, > Isuzu,Volvo,BMW etc. All expensive to buy new but theres always a > bargain to be had if you are resorceful. Check out the second hand > marine market if you live near the sea. > > Best regards > John Smith. > > --- In [EMAIL PROTECTED], Justin Anderson <[EMAIL PROTECTED]> wrote: > > Hi All > > > > I have just aquired a 11KVA alternator. I now need an engine to > turn the > > alternator. I would like to use a petrol engine. BUT there are > several > > problems(so I can change it over to ethenol when every thing is > working :) ). > > > > The engine must run at 1500 rpm. From what I have gathered there > is not much > > power available from a petrol engine at this rpm. I have spent > several hours > > looking on the internet for power curves for 1.6L to 3L engines > but have not > > been not been succesful. I would probably need about 17KW brake > power at > > 1500rpm if I want to change it to ethanol. I was thinking of using > an old > > MBenze engine(220 or so). > > > > Any advice would be welcomed... > > > > cheers Justin ------------------------ Yahoo! Groups Sponsor ---------------------~--> FIND OLD SCHOOL FRIENDS and OLD FLAMES Click here to start your search at Reunion.com today! http://us.click.yahoo.com/NFsLKA/Dn2DAA/ySSFAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
