T-Pain Is On A Boat: Re: [Electric Boats] Re: 55' wooden hull in SFBay

Wednesday, August 3, 2011

Re: [Electric Boats] Re: 55' wooden hull in SFBay

Out of curiosity, wouldn't an induction motor work be very well-suited to this applicationation? I am thinking about losses when spinning the motor. In a bldc motor, when it is spun, it generates watts since there is no way to turn off the magnetic field. This is going to be a drain on power delivered from the diesel to the prop. In an induction motor, if the rotor has no field, then wouldn't energy losses in freewheeling be reduced to just the bearing friction?

Of course, induction motors come with their own issues.

Cheers,

/Jason

On Aug 3, 2011, at 11:29, "Mark n Angela" <mstafford@natca.net> wrote:

Dave,

I'll most likely use Eagle NRG Helical Offset Tooth (White - 32mm wide, 8 degree H.O.T. pitch) belt drive, with about a 4:1 motor:prop ratio, no additional clutching. Diesel's transmission in neutral will allow pure electric. In other words, if prop is turning, e-motor will be turning.

It's a modern ZF transmission with thin ATF lube, but there will still be up to maybe 10% parasitic drag loss. And when straight diesel motoring, electric motor will no-load spin, robbing maybe 4% engine:trans:prop efficiency.

In Western terms: everything's a compromise. Or to put it more Zen-like: life is a balancing act.

Mark Stafford

--- In electricboats@yahoogroups.com, Dave Kellogg <inganear1@...> wrote:
>
> Marc,
> Just curious, what clutching mechanics were you planning on using with the hybrid thoughts when using one or the other or both together... Dave K
>
>
> ________________________________
> From: Mark n Angela <mstafford@...>
> To: electricboats@yahoogroups.com
> Sent: Tuesday, August 2, 2011 12:50 PM
> Subject: [Electric Boats] Re: 55' wooden hull in SFBay
>
> Eric,
>
> To take Myles off the hook, it is Mark Stafford who ripped out a 2500 pound GM271 diesel from a 1983 Herreshoff Marco Polo 55' sailboat named Constance in San Francisco Bay, and put in a 96volt DC GE 23hp motor and 1300 pounds of used and abused lead acid batteries.
>
> Batteries were the hardest part for installation and maintenance.
>
> I'm going hybrid: installing a 30hp ListerPetter diesel in parallel (either electric and/or diesel can drive the prop). I had planned to go serial hybrid (generator to batteries to e-motor), but my budget would not allow.
>
> Mark Stafford
>