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Old 20-12-2012, 15:53   #61
Nearly an old salt
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Originally Posted by Blue Stocking

Somewhere in the Atlantic, there is a BIG Blue Marlin with at least 1 Walker rotor in his belly. Lost it in '71.
I heard of that happening, but we crossed in that boat we had it out virtually the whole time , two or three whales had a sniff but that was it. Mind you I'm an awful fisherman , so most things ignore whatever I trail


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Old 26-12-2012, 23:34   #62
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Join Date: Mar 2012
Location: South West Pacific
Boat: Sloop, Alu, Via52, 15m
Posts: 8
Re: Permanent Magnet Generator on Propshaft

Hello to everybody

I will contribute some real experience;

Since 2003 I am running a so called Fisher & Paykel washing machine motor on my boat, absolutly successful. My boat has twin engine systems one F&P motor on each shaft, see att.#1.

I spent more than 3 month full time testing/ wiring and developing the system. I thought I could make some cash with it, had it on ebay and different websites. I sold one.

Here is the info sheet I put together 10 years ago:

Power under sail

Finally a prop shaft alternator which really works, 20amps+ under sail !!
This is 42 pole 56 magnet 3-phase alternator / generator.., a slow speed alternator which can be configured to start charging from 60rpm.
In the most common version and 12 volt it starts charging at 150rpm, at 200rpm charge is 6.5amps, at 250rpm- 9amps, at 350-13amps, at 450rpm- 16amps, over 500rpm 18amps.

There are different stator configurations available, 12/ 24/48 volt .
There are outputs available up to 30amps +, with higher cut in speed, as well lower outputs with really low cut in speed.

Transmission ratio is only 1:1. So, no need for extra space at the coupling from the gearbox to shaft.
Generator is driven via a V-belt, a pulley put between the gearbox flange and the flexible coupling. The shaft will have to move max. 10mm back. This should not be a problem.

It is fitted with an electro magnetic clutch so it can be disconnected when the main engine is running to prevent overcharging the batteries.

At the moment I can supply mounting brackets for the following gearbox:

Hurth HBW250

As well a universal mounting bracket if the generator is not driving from the gearbox flange.
I can machine and supply the driving pulley which goes between gearbox flange and flexible coupling, or a taper lock pulley which slips over the propeller shaft, no need for machining anything on the shaft, if you want to mount the generator somewhere along the shaft .

Did you know that even if you have fitted your yacht with a feathering propeller that it is possible to drive an alternator from the shaft. A feathering propeller stays spinning in either the forward or reverse position, depending on the position of the axis of the blade.
In the case of an Autostream feathering propeller the shaft keeps spinning in the forward position. To stop your Autostream feathering propeller you have to put your gearbox into reverse.

Sailing output results from a 19 inch 3-bladed Autostream propeller:

at 5.5 knots charging 11amps @ 330rpm
at 6 knots charging 13amps @ 390rpm
at 6.5 knots charging 15amps @ 440rpm
at 7 knots charging 19amps @ 500rpm

With fixed blade propellers much higher output, over 30amps@12volt can be achieved at lower boat speed
Rotor diameter: 280mm
Pulley clutch diameter: 160mm
Total length: 210mm + 45mm rotor knob

I have tons of info for the F&P motor:
as well I have a couple of them I would sell.
with & without 12V clutch, V-pully for Hurth HB250 gearbox and bracket.

I have more then 10 milk crates full of parts if somebody wants to persue further manufacturing, plus all the technical info.

more info about F&P power see: The Back Shed

search for "carl1" I have put some of my info on this website.

I can post more pictures and info.

I used one for a wind generator project, still working on it.

cheers & Happy New Year

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