Power output against engine speed

[jmw]

If I have an S1100 that produces 16hp at 2200rpm, what would be the power output at 1500rpm.
If it was roughly linear, my guess would be 11hp (15/22*16).
My supplier is telling me that a gen head driven by this engine at 1500rpm would struggle to produce 4.5kW of electricity, and sounds like a load of rubbish to me.

Anybody got any views/opinions?

Mark

[mobile_bob]

it sounds like you want to direct drive a genhead for 50hz operation?

if so thats cool, less to worry about

as for how much power, you will be able to make probably a bit over 7kwatts at 1500rpm at a one hour rating
and probably around 5.5kwatts continuous rating, maybe closer to 6kwatts with a 80% efficient genhead.

if you bank on 5-5.5 kwatt continuous i think you will be fine,

will you be using a water pump and tstat?  positive cooling and accurate coolant temp control helps a lot in how much
power the engine can make reliably in my experience.

ymmv

bob g

[jmw]

Bob,

Yes, I have a pump and thermostat (89 degrees C) and the thermostatically control 12vdc radiator fan, so temperature is well under control.

I'm just confused as to why the supplier is telling me that 4.5kWs is a struggle. I think there may be an ulterior motive here. I did read somewhere that these engines can blow their head gaskets when directly coupled - not as much 'give' as a belt driven setup.

[veggie]

JMW,

My testing with the Changfa S195's shows that the BHP line is almost linear all the way down to 1200 rpm.
16 hp @ 2200 should equate to about 10.9 hp @ 1500 rpm.

Now...using the 2:1 rule for HP per kw of generator, you should be good for a maximum of 5.4 kw from your gen head.

Where there could be some variation is in the manufacturer of the engine. I think we can be fairly confident if dealing with a Changfa engine. Other versions of the Changfa may differ due to variations in quality, clearances, and finish.

veggie

[mobile_bob]

yes some of the engines will blow head gskts, and there are two main types
the steel cored fiber gasket and the copper sandwich style gskt

the oem changfa steel core gskts can be made to fail by overloading the engine, or rather overloading the gasket
but the "gaskets to go" guy can fix that issue, i know i fixed me up with a superior quality gskt that i have abused
severely in testing.

i really don't think you will have any problems at all up to 6kwatts at 1500rpm with a good gskt, so long as you have
the cooling well provided for.(intermittent one hour rating, and maybe down to the 5.5 kwatt continuous)

bob g

[vdubnut62]

I've given my 1100 a really hard way to go direct driving a 12kw 1800rpm head, here is a link to a  pic.

http://www.microcogen.info/index.php?topic=645.0

Hopper cooling at that power level is out of the question long term! I will get the radiator  and fan set up when I get a few family matters settled.
I figure probably 7.5kw max with the rack wide open & smoking like a tar kiln ---  that's probably optimistic and no way will it pull that very long!
But the head gasket and O-rings seem to be taking the stress just fine.
Ron

[mobile_bob]

thats really strange Ron,

my 195idi will pull a full 7100 watts with just a hint of gray smoke, and it too is direct drive 1800rpm driving
an st7.5 head.

i would expect the 1100 should be substantially stronger than that?

maybe it is elevation? i am at about 350ft above sea level, how high are you?

bob g

[vdubnut62]

Well, it depends on what I'm smokin'
1140 feet, I'm on the first tier of the Cumberland Plateau, and the farm is 'way up on top at 1660 feet.
And my clamp on meter is crap, so I am giving just a WAG really. That would be the house with 4 cordless phones 2 sat receivers a TV,
digital clocks a chest freezer, 2 refrigerators, 3/4 hp blower on furnace, 3 stove elements, a 50 gal water heater.
The 4th  element was the straw that broke the camel's back
I told ya I was real perticler about my testing.
Ron