Sorry, got my numbers mixed up. I have the 241 not the 271. I don't
have enough room for a big genset and don't want the first mate tempted
to run the A/C all night. :-)

Baja-Mo wrote:
I don't want an engine driven pump - I have a 6.5 kw genset and will
use 120 vac.

According to the cat spec sheet
http://www.catpumps.com/select/pdfs/PUMP/231-271.pdf

the 271/277 has max rpm of 1450 - so can't use direct drive 1725 ac
motor. Would need the 241/247 pump - max's 1725 rpm and 3.6 gpm at
that speed.



On Tue, 28 Oct 2003 16:43:12 -0500, Glenn Ashmore
wrote:


That particular news release was for a new 3" series. The 2540 has
always been rated for .4 gpm but driving them at max output takes a lot
of extra detail in the design work and you have to push 4.5 gpm of
seawater through them. Keeping the product under .3 gpm is a lot safer
and more energy efficient.

I am using a pair of SW30-2540's to get 800 gpd using an engine driven
Cat 271. I gave up on trying to drive the pump with an electric motor.
It takes 2 HP to push 3.5 gpm at 850 PSI. That takes 125 amps. I
would rather let the alternator charge the batteries for an hour while I
make 35 gallons of fresh water on a separate pump.

Installing an engine drive is slightly more expensive than electric but
when you add in the larger alternator and bigger battery bank it is
actually a lot cheaper. The downside is that you are limited by the
engine RPM but with careful choice of pulley ratios you can get maximum
water output at the same time the alternator reaches its peak and still
have a reasonable cruising speed. I balanced my system atan engine RPM
of 2200. The pump will be turning 1750 and the alternator 4200. That
will give me a decent cruising speed and maximum output of water and
amps. Idling at 1600 RPM I will get 75% output and still load the
engine nicely to reduce cylinder glazing and keep the carbon blown out. .




--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com