Mike
Interesting. You draw 5 amps and locks the prop in regen position. Just the kind of information i am looking for!!! Have you tried to rotate the locked shaft and how much force did it take to rotate it?
While 5 amps seems high i would expect a start up battery draw. A motor/generator needs a magnetic field to operate so unless you have a permanent magnet motor the magnetic field needs to be created electrically thus the draw. I am just surprised by the amount but i have no clue if that is typical or a fault. Anyone care to comment?
It is probably the magnetic field that locks your prop in position and the pitch of the prop does not create sufficient rotational force to overcome the magnetic field to start and maintain regeneration. The standard prop configuration has the blade positioned such that when the prop is being dragged through the water, the main force resultant is to create drag and the lesser resultant is to create rotation. ( In my present thinking this needs to be switched to make regen possible.) I am trying to find numbers for various conditions to determine the starting torque for regeneration.
--- In
electricboats@ yahoogroups. com, Mike <biankablog@ ...> wrote:
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> Gramplarry:
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> I can't speak for others but, on my 8 ton 30 foot Nonsuch catboat I have not been able to get the regen to work. My throttle control has detents for the regeneration position but, when I engage it it locks the prop and draws 5 amps from the battery bank. I have the original 3 blade RH 16" diameter 13"pitch  prop installed. So I don't know how big of a prop I might have to go to make it work. I also have clearance issues in going to a bigger prop. (BTW I appreciate your websites prop sizing info, very informative. ) I'm very happy with my systems performance otherwise. It's not critical that I get regen to work but, it would be nice. Though it's not at the top of my list of things to spend too much time on at this point.
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> Capt. Mike
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http://biankablog. blogspot. com> Â
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> --- On Sat, 3/6/10, gramplarry <pfister.l@. ..> wrote:
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> From: gramplarry <pfister.l@. ..>
> Subject: Re: [Electric Boats] propellers
> To:
electricboats@ yahoogroups. com> Date: Saturday, March 6, 2010, 6:16 PM
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> this discussion sounds to me that regeneration has been discussed and even tried but seems to have been less successful than everyone would like. by this i mean pure regeneration not just matching the prop to sailing speed.
> what happened and what are the reasons for not being successful.
> how much drag for regeneration would be acceptable?
> how much power needs to be supplied by the propeller to the motor to have regeneration?
> what propeller rpm and torque would start and maintain regeneration.
> How much power should be regenerated with time.
> what usage? house batteries and power batteries of both etc.
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> --- In electricboats@ yahoogroups. com, "aweekdaysailor" <aweekdaysailor@ ...> wrote:
> >
> > I believe, but can't yet prove, that the one area where "regeneration" might actually be practical is in what Kevin P calls "electrosailing" - matching the prop rotation to the boat speed so that it's regenerating about 50% of the time (very low wattage mind you) The point of this is not really regen, but rather nullifying the prop drag and getting the extra 1/2 to 3/4 knot of speed. Over a sufficient distance, this extra speed is the practical equivalent of a feathering prop (without the drawbacks) and nearly net zero energy use.
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> > I currently have a 3-blade, so the above is more necessity than choice.
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> > -K
> >
> > --- In electricboats@ yahoogroups. com, "dennis wolfe" <dwolfe@> wrote:
> > > I bet a large diameter, high aspect ratio 2 blade prop would give excellent performance as a sail aux drive, especially if a method could be devised to lock the prop in the vertical position hiding in the wake of the skeg. A folding prop that would work in reverse would be even better.
> > >
> > > Denny Wolfe
> > > www.wolfEboats. com
> > >
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