Larry wrote:
Saw a 380A 24V, gear-driven alternator for a big bus at the electric
shop while buying my Chevy stepvan a new
starter..........DROOL....(c;

It had oil passages the big diesel pumped engine oil through the core
of it to cool it!

That'll recharge that big Heart Inverter battery.....quick!

To answer your question, alternators are very efficient. The only
problem I'd see with a huge alternator is the weight of the unit
making the engine lean to one side and mis-aligning the shaft, which
would be BAD.....and the flywheel effect of a larger armature
starting and stopping and changing engine speeds. I'd be afraid of
the weight/alignment issue in a small sailboat engine bending the
mountings over to one side. I suppose you COULD mount the alternator
off the motor but then the pull on the belt a big alternator would
pull would pull the engine to that side all the time, probably
ruining the engine mounts. My friend Geoff had that trouble with his
Yanmar 3GM and a huge car air conditioner compressor that used R-12
to run the fridge's big cold plate. You could SEE the engine pull
towards the externally-mounted compressor.....That's got to hurt
shaft bearings.

I am avoiding side load all together. Welded up a frame in heavy 6x2
channel that bolts tothe stringers in front of the engine with a short
1.5" diameter shaft on double 1.5" pillow blocks. The Niehoff and Cat
watermaker pump mount on the bracket with all the V-belts and pulleys on
the shaft. It is connected to the damper plate with an Aquadrive.
(Basicaly a very short CV joint) The engine can wobble all it wants
without any side load.

I am still a little worried about the total horsepower coming off the
front though. I am figuring I will need about 9HP with the alternator
and the pump running flat out. The Yanmar installation manual does not
give limits for this kind of mount. It is more concerned with side load
on directly attatched drive pulleys.

--
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

What worries me on off-engine powered equipment is the belt tugging
away on the engine to that one side. On Geoff's old boat, you could
see the engine vibrating sideways as the freon pump went over TDC each
cylinder, then releasing as the piston went down slackening the load.
It's GOT to pull the engine mounts and wear them that way. This is
not an issue where the load is mounted directly on the engine and not
pulling against the engine mounts. Engine mounted, however, needs a
little weight and balancing, too. I see too many engines, especially
in outfitted sailboats with limited space, that have too many addons
bolted to ONE SIDE of the engine, unbalancing the weight distribution
on the engine mounts, which again must be bending with that load.

Either way, I'd think it would be hard on shaft alignment, worse after
time, wearing out those shaft bearings and cutlass bearing.



Larry W4CSC

"No, NO, Mr Spock! I said beam me down a WRENCH,
not a WENCH! KIRK OUT!"

Larry wrote:
What worries me on off-engine powered equipment is the belt tugging
away on the engine to that one side. On Geoff's old boat, you could
see the engine vibrating sideways as the freon pump went over TDC each
cylinder, then releasing as the piston went down slackening the load.
It's GOT to pull the engine mounts and wear them that way. This is
not an issue where the load is mounted directly on the engine and not
pulling against the engine mounts. Engine mounted, however, needs a
little weight and balancing, too. I see too many engines, especially
in outfitted sailboats with limited space, that have too many addons
bolted to ONE SIDE of the engine, unbalancing the weight distribution
on the engine mounts, which again must be bending with that load.

Either way, I'd think it would be hard on shaft alignment, worse after
time, wearing out those shaft bearings and cutlass bearing.

What I am doing is kind of hard to visualize. The only places I have
seen is it on an Arodyne 46 and a USCG MLB. The heavy auxillaries are
mounted off the engine. Nothing but torque reaches the engine. It can
put stress on the engine mounts but compared to the propulsion torque it
is minor.

It will be about 6 months before I can set the engine and the
auxillaries but then I will post some pictures and you can see what I mean.

--
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