NICE!!! Link.
--- In electricboats@yahoogroups.com, GeoMar Logistics <geomarlogistics@...> wrote:
>
> *An ICE outboard run for prolonged periods at 5000 RPM will not last long
> and the fuel consumption at that throttle setting would be horrific. Having
> said that, electric motors have a pretty flat torque curve which should
> allow for a prop that takes a bigger bite either through pitch or increased
> diameter. Most outboard lower units have a horizontal tab above the shaft
> which limits the diameter of the prop. The following link may be helpful in
> determining your best prop size.
> http://www.rundquist.com/how_change_pitch.htm
> Good luck,
> George
> *
> On Sat, May 21, 2011 at 7:10 PM, rob linda <rob_linda_2000@...> wrote:
>
> >
> >
> > Kevin,
> > Thanks for responding.
> > We also concluded, that the weight of these AC induction motors is to high
> > for use in an outboard, hanging from the stern.
> > We'll probably will go with a brushless Etek/Mars motor, that seems to have
> > more rpm, than the brushed ones.(4000 rpm)
> > The ICE outboard runs at about 5000 rpm on the plane
> > We're hoping to compensate for the "lacking" 1000 rpm or so, by fooling
> > with higher pitched /diameter props and different outboard legs.
> > Does anybody have an opinion on the feasibility of this?
> >
> > Rob on Linda
> >
> > --- On *Thu, 5/19/11, Kevin Pemberton <pembertonkevin@...>* wrote:
> >
> >
> > From: Kevin Pemberton <pembertonkevin@...>
> > Subject: Re: [Electric Boats] Electric planing dinghy
> > To: electricboats@yahoogroups.com
> > Date: Thursday, May 19, 2011, 6:26 PM
> >
> >
> >
> > I guess you are asking about AC induction motors sold by EV companies.
> > Induction motors cover a much broader spectrum.
> >
> > The industrial controllers used on 3ph motors can run the RPMs up to
> > double or more the rated RPM of the motor. According to literature on
> > the net 1800RPM motors when used with VFDs are the most efficient. The
> > controller I use with my 1800RPM motor will give 2.5 times the design
> > speed of the motor. The torque flat lines at 1800RPM, but this should
> > not be a problem as the motor still gives 100% of the torque it was
> > designed to give. DC motors give RPM based on voltage, induction motors
> > give the RPM based on frequency of the drive. You will not be able to
> > get more HP from the motor because of the controller design, limits
> > current, based on the motor connected to it, so size the motor
> > correctly. AC induction motors are larger and heavier than the DC motors
> > of the same HP. Inside a boat no problem, off the transom? Maybe.
> >
> > You could use industrial equipment for your job, but high voltage (over
> > 48) requires much more attention to legal issues. I invision supply
> > inverter(24 to 220), VFD, and motor under the hood of the outboard. 24v
> > supply cables into the hood completely water proof. Cooled using water
> > and coils around the motor and water heat sinks on the VFD and inverter
> > housing.
> >
> > Seems like a lot of work!
> >
> > Kevin Pemberton
> >
> > On 05/16/2011 03:49 PM, rob linda wrote:
> > > We're still trying to make up our mind about the rpm issue, one
> > > encounters, if replacing the ICE power head on the outb
> > > oard with an electric motor for planing speed.
> > > Miles suggested belt gearing, which means extra bearing at high end of
> > > drive shaft.
> > > There also may be props pitched high enough, if we can find them.
> > > There is the Agni motor, which is pricey and probably overpowered.
> > > We're focussing at the moment on using an AC induction motor like
> > > this:
> > http://www.electricmotorsport.com/store/ems_ev_parts_motors_ac9.php
> > > At 6000 rpm this seems like a candidate.
> > > Looking at the power/rev curve :
> > > http://www.electricmotorsport.com/store/pdf-downloads/AC_Drives/AC9.pdf
> > > , it has this "bump" at 2000 rpm and looks like the power curve for a
> > > planing dinghy, where the "bump" happens while "getting on the plane",
> > > or am I guilty of naive and wishful thinking.
> > > Any opinions on this ?
> > > Anybody has experience with AC induction motors?
> > > Thank you
> > >
> > > Rob on Linda
> >
> > --
> > AspireOne Netbook running Ubuntu 11.04
> > Safe, Secure, Easy to use, Free Open Source Linux OS.
> > Leaving Virus worries to the Windows Users!
> >
> >
> >
>
>
>
> --
> *No trees were harmed in the creation of this message, though a significant
> number of electrons may have been inconvenienced.
> **
> George Johnson
> GeoMar Logistics
> Jomtien, Chonburi
> Thailand*
>
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