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Kubota Z482 - Question Regarding Alternator


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  #11  
Old 02-07-2018, 12:19:50 AM
AngrySailor AngrySailor is offline
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Default Re: Kubota z482 - Question Regarding Alternator

Pegasuspinto, see the pics in runaway 12v149 thread for an explanation of our shift to a parallel dimension... it wasn't CERN that caused that

By the power curve posted, that engine makes 5hp at 1800rpm or about 6.7kw. Usually the engine is rated double the generator capacity so it's not going to work well at 1:1... maybe steady 4kw lugging like crazy. There are ways around this, or marry parts that work together may be easier/better solution. Just my $0.02


Edit, I didn't notice the BSFC was posted i that chart... if you had a 2 pole generator or reduction gearing/belting, you would get almost double the power for minimal extra fuel, less friction losses. That engine needs a 2 pole 3600 rpm direct drive generator for maximum efficiency!

Last edited by AngrySailor; 02-07-2018 at 12:30:34 AM. Reason: Autocorrect
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Old 02-07-2018, 12:42:56 AM
Vanman Vanman is offline
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Default Re: Kubota z482 - Question Regarding Alternator

I would be highly doubtful that the engine would be more efficient screaming away. Speaking of that, is the timing adjustable on these? Optimizing the timing for the sane rpm of 1800 would make it even more efficient at the slower speed.

But here's another question- how many kw is the existing 4 pole generator?

As an aside, there is absolutely no way I would ever deliberately set up an engine to run at 3600 rpm. You've got already got a 4 pole generator, it'll bolt up to the nice engine you already have. If the generator is 4 or 5 kw, bolt 'em together, adjust the governor to 1800, and enjoy a sweet generator set!
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  #13  
Old 02-07-2018, 12:55:17 AM
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Jim McIntyre Jim McIntyre is offline
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Default Re: Kubota z482 - Question Regarding Alternator

Quote:
Originally Posted by AngrySailor View Post
By the power curve posted, that engine makes 5hp at 1800rpm or about 6.7kw.
Look again. It's 5 kW at 1800 rpm.


Quote:
Edit, I didn't notice the BSFC was posted i that chart... if you had a 2 pole generator or reduction gearing/belting, you would get almost double the power for minimal extra fuel, less friction losses. That engine needs a 2 pole 3600 rpm direct drive generator for maximum efficiency!
No. The BSFC is actually better at 1800 rpm than at 3600 rpm.
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Old 02-07-2018, 01:15:45 AM
pegasuspinto pegasuspinto is offline
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Default Re: Kubota z482 - Question Regarding Alternator

Quote:
Originally Posted by Jim McIntyre View Post
Look again. It's 5 kW at 1800 rpm.
It DOES say "engine horsepower (kw)" Kinda goofy
container gallons in liters?
rope feet in meters?
I could go on but it hurts the brain!
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Old 02-07-2018, 01:22:06 AM
AngrySailor AngrySailor is offline
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Default Re: Kubota z482 - Question Regarding Alternator

Quote:
Originally Posted by Jim McIntyre View Post
Look again. It's 5 kW at 1800 rpm.




No. The BSFC is actually better at 1800 rpm than at 3600 rpm.
Does it use DOUBLE at 3600? For TWICE THE POWER?

And your right it IS Kw, damn phone posters... that's even worse though! It's only a 2.5 kw generator now.

I may have jumped too soon
Wait... does it say g/kWh? If so you're right

We can't argue this without knowing actual load really.

Last edited by AngrySailor; 02-07-2018 at 01:33:47 AM. Reason: Eating crow
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Old 02-07-2018, 08:52:46 AM
Wayne 440 Wayne 440 is offline
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Default Re: Kubota z482 - Question Regarding Alternator

Normally, I'm an advocate for "slow" running machines. But at some point the bore and stroke get low enough that 3600 is relatively slow - a Z482 is about half the displacement of a DJB. I would have no issue with that engine for standby use at 3600, the stroke is 2.68 inches, and bore 2.64 so the piston speed is not all that fast.

That said, there is little doubt that it would last longer at a lower speed.
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Old 02-07-2018, 10:55:54 AM
gnucklehead gnucklehead is offline
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Default Re: Kubota z482 - Question Regarding Alternator

That engine isn't very smooth at 1800. If I were designing from scratch, I would run it at +/-2600RPM, which is the peak in the torque curve, and belt it up or down.. The governor on your engine might be limited, and I wouldn't be afraid one bit to run it at 3600, if that's where the governor range is. Depends on the former application of the engine. There are models designed to scream. it's a sub-500cc z482... Don't try to compare it to other engines, except maybe a yanmar 2TN.
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Old 02-07-2018, 12:55:15 PM
gnucklehead gnucklehead is offline
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Default Re: Kubota Z482 - Question Regarding Alternator

To answer the OP's question - No, not direct drive. Has to be belted.. In theory you could bypass two poles and get some sort of 60Hz at 3600, but the rotor was not designed to spin that fast..
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Old 02-07-2018, 12:58:00 PM
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Default Re: Kubota z482 - Question Regarding Alternator

Quote:
Originally Posted by AngrySailor View Post
...Wait... does it say g/kWh?....
Yes. That's what the 'S' in BSFC means - the fuel consumption is based on a 'per kW' (or 'per HP') basis.



https://en.wikipedia.org/wiki/Brake_...el_consumption
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Old 02-07-2018, 02:42:57 PM
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Default Re: Kubota Z482 - Question Regarding Alternator

One KW is equal to 1.34102 horse power. So 5 KW is equal to 6.70 HP
The little Z482 is a hell of an engine. I had an early Kubota B5100D and it would pull its little heart out. Only drawback to mine was it was a thermo-siphon cooling system, No water pump. Later ones had a water pump.
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