kabota generator

[pabusnut]

Back to the Kubota generator.  I have a D600 3 cyl. that I am using to make my 7.5 KW generator.  It will be belt drive to an 1800 rpm generator head.  I will be running it at about 2825 to get the 11 continuous HP that the generator head requires for 7.5 KW.  The 2825 RPM also corresponds to about the peak torque of 20.5 Net continuous FT LB. 

I should be able to run everything electrical I have and not choke the generator.

On the Mercedes thread I had an 83 300SD that I loved, but to fix the heater controls was going to cost me $900 with used parts!  --Then the transmission blew.  The body was perfect and had unusual two tone brown leather seats.  It got up to 30 mpg on the highway, and was the best riding car I've had to date!  Unemployment makes you get rid of the unimportant things.  Thankfully I kept the bus!

Steve Toomey

PAbusnut

[artvonne]

  The speed of the engine is irrelevant, you must spin the generator head (alternator) at the exact speed its designed for. That will generally be 1800 rpm, or 3600 rpm. The reason is that eveything running on AC uses 60 cycles. As the generator turns, the field is cut, either twice, or four times per revolution, depending on the number of poles. Each time the field is cut, the cycle reverses. 2 pole alternators must turn 3600 rpm to make 60 cycles, 4 pole alternators must turn 1800.

  From purely an efficiency standpoint, direct drive is the best choice, as belts or gears or chains use power that is simply wasted, are noisy, and require regular maintenence. Obviously, if the engine cannot deliver enough power for the alternators rated output, a reduction ratio will work and you simply spin the engine faster to make up the difference, but you could also build it direct drive and simply derate the generator and protect it with lower amp breakers. 

[luvrbus]

You don't derate the generator head KW's are achieved with HP from the engine you can make a 10 KW from a 8KW head with just a HP change.
RPM changes the cycle a 60 cycle 1800 rpm generator can be change to a 50 cycle by dropping the RPM to 1500 rpm and or a 50 cycle to a 60 cycle by changing to 1800 rpm it's not really a rocket science.
I have watched Bill Harris in VA change 3600 rpm heads to 1800 rpm heads without much problems and time but he is the best in the business when it comes to generators of all sizes I should have paid attention then I would know how to do it lol 

good luck

[artvonne]

  I think you misunderstood what I meant. If he is putting a 10KW head on an engine that cannot deliver enough power to provide the heads full rated load at that rpm, the engine will lose rpm and the head will burn up. By simply stating it is now X KW rated capacity and putting breakers rated just above that capacity, the head will never see its full rated load, and the engine wont ever run out of power. In fact, a head that never sees full load will run cooler and last longer.

  I know the speed changes the cycles, I did not know you could change a head from 2 to 4 poles or vice versa, but if possible it would allow the engine to make more power.

[JohnEd]

I kinda see both points:  Heads are most likely created in really big jumps such as "up to 10Kw".  Hook that up to a 5KW rated motor and the "system becomes rated for what the engine can do.  But there has to be a limit and by simply hooking that 10KW head up to 20KW worth of motor will only get you 10KW and then your breakers/fuses will pop.  Fuse it for 20KW and it will melt down with that load.  And I think that is the root understanding of you both.  Some here might be "cornfussed" and I speak to them.

John

[luvrbus]

John, your are right with the head jump most of the time 1 head will work for 3 or 4 different KW setting with different hp engines then they jump again 

good luck

[silversport]

my 81 300TD wagon avg. 27, 30.25 going down I-5 @ 65mph
Robert