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Home > Archive > Alternative Power sources > September 2005 > diesel, exaggerated claims?
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diesel, exaggerated claims?
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| Robert Morein 2005-09-13, 10:21 pm |
| How does this thing work:
http://www.generatorsales.com/order...page=yanmar_4kw
It appears to have the same 406cc displacement as the 10 hp Yanmar found in
5kw gensets, yet this one runs at a slower speed, which would have to be
either 1800 or 1200, yet claims to produce 4 kw.
The thing weighs only 165 lbs.
Even the aluminum-framed NATO OTAN field generator weighs 143 lbs, and puts
out 2 kw, at 3600 rpm.
At 1800 rpm, the shaft horsepower would, I think be between 3 and 4, which
at 70% efficiency gives a max of about 2 kw.
By comparison, the original "China diesel" weighs 885 lbs. dry:
http://www.hardydiesel.com/gen/8kw.html
It produces a little more horsepower, and it's water cooled.
It seems to me that an 1800 rpm aircooled genset rated at 4kw would have a
minimum weight of about 500 lbs.
So what is this product giving up?
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| Harry Chickpea 2005-09-13, 10:21 pm |
| "Robert Morein" <nowhere@nowhere.com> wrote:
>How does this thing work:
>http://www.generatorsales.com/order...page=yanmar_4kw
>It appears to have the same 406cc displacement as the 10 hp Yanmar found in
>5kw gensets, yet this one runs at a slower speed, which would have to be
>either 1800 or 1200, yet claims to produce 4 kw.
>
>The thing weighs only 165 lbs.
>
>Even the aluminum-framed NATO OTAN field generator weighs 143 lbs, and puts
>out 2 kw, at 3600 rpm.
>
>At 1800 rpm, the shaft horsepower would, I think be between 3 and 4, which
>at 70% efficiency gives a max of about 2 kw.
>
>By comparison, the original "China diesel" weighs 885 lbs. dry:
>http://www.hardydiesel.com/gen/8kw.html
>It produces a little more horsepower, and it's water cooled.
>
>It seems to me that an 1800 rpm aircooled genset rated at 4kw would have a
>minimum weight of about 500 lbs.
>
>So what is this product giving up?
Carbs?
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| Robert Morein 2005-09-13, 10:21 pm |
| Further info.
According to the Yanmar chart, the 406cc engine produces 6 hp at 1800 rpm.
If the alternator is 70% efficient, that would be 3133.2 watts, yet they
claim 5 kw maximum output.
"Robert Morein" <nowhere@nowhere.com> wrote in message
news:BuydndgqCe2A6LreRVn-gQ@giganews.com...
> How does this thing work:
> http://www.generatorsales.com/order...page=yanmar_4kw
> It appears to have the same 406cc displacement as the 10 hp Yanmar found
in
> 5kw gensets, yet this one runs at a slower speed, which would have to be
> either 1800 or 1200, yet claims to produce 4 kw.
>
> The thing weighs only 165 lbs.
>
> Even the aluminum-framed NATO OTAN field generator weighs 143 lbs, and
puts
> out 2 kw, at 3600 rpm.
>
> At 1800 rpm, the shaft horsepower would, I think be between 3 and 4, which
> at 70% efficiency gives a max of about 2 kw.
>
> By comparison, the original "China diesel" weighs 885 lbs. dry:
> http://www.hardydiesel.com/gen/8kw.html
> It produces a little more horsepower, and it's water cooled.
>
> It seems to me that an 1800 rpm aircooled genset rated at 4kw would have a
> minimum weight of about 500 lbs.
>
> So what is this product giving up?
>
>
>
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| Solar Flare 2005-09-13, 11:21 pm |
| "Maximum" may include the flywheel weight of the engine also.
"Robert Morein" <nowhere@nowhere.com> wrote in message
news:5OadnYmu9azB5LreRVn-1w@giganews.com...
Further info.
According to the Yanmar chart, the 406cc engine produces 6 hp at 1800 rpm.
If the alternator is 70% efficient, that would be 3133.2 watts, yet they
claim 5 kw maximum output.
"Robert Morein" <nowhere@nowhere.com> wrote in message
> news:BuydndgqCe2A6LreRVn-gQ@giganews.com...
found[color=darkred]
> in
> puts
which[color=darkred]
a[color=darkred]
>
>
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