[Nottingham] Off-topic: Electric propulsion

[Martin]

> On 6 October 2011 16:55, Paul Sladen <notlug at paul.sladen.org> wrote:
>> Enough with the motorcycles, but I do currently have one of the same
>> Lynch motors in sitting in a crate and lined up for a little project;
>>
>> I acquired the Lynch motor for fitting to the narrowboat—once I
>> figure out how to parallel it with the diesel engine in a sane
>> way.  If anyone knows anything about magnetic or centrifugal clutches,

A few thoughts:

1: Abandon the complicated lossy mechanics and go solar-diesel-electric?

That is, use the Lynch motor as your sole direct drive propulsion. The
electric power comes from your batteries. They are charged up by your
solar panels, or by running the diesel coupled to a generator
(multiple alternators?). Even if your diesel generator cannot provide
enough maximum amps for your motor, that doesn't matter in that you
have the batteries to supply the excess. The diesel generator merely
needs to supply at least the average running current.

Lash up a few alternators from a few scrappers to get 12v at a few hundred amps?


2: Use a differential drive

Both the diesel engine and electric motor stay permanently engaged via
a differential. The shaft output to the propeller is the sum of the
two. Just don't run the electric motor in reverse whilst running the
diesel! There will be enough cylinder compression resistance for the
diesel not to be turned when running the Lynch. You might need a brake
on the Lynch to stop the diesel driving it when not energised.

An aside to that is that if the Lynch can be run as a generator, and
you put a brake on the final output shaft, you could run the diesel to
drive the differential to run the Lynch as a generator.

As for the gearing/mechanics... You could even scavenge an old-style
car rear axle and mount the Lynch above your existing diesel. The diff
axle is then mounted vertically with a bevel gear to the diesel. The
centre drive shaft output then connects back down to your existing
prop drive shaft via a chain or belt drive.


3: You could 'cheat' and use hydraulic motors for a combined
diesel-hydraulic/electric-hydraulic drive. The mechanics would be easy
and the valves and pipes are easy. However, I'd be a little leery of
the energy losses (wasted as heat) through the hydraulics.


Whichever way you go, that all sounds like some rather adventurous mechanics!


Let us know how it all goes?

Do we get invited to an inaugural cruise?

Cheers,
Martin