Coaxial generator development

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On Aug 2, 11:17 pm, Ernest Christley wrote:


I need to verify, but I'm fairly certain that the reg/rec I'm using is a
switching type. It turns off the line when the power isn't needed.
Saving the generator from producing heat in both the rotor/stator and
generator.

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Dear Ernest,

I'm afraid that only addresses the power OUTPUT, not generation. So
long as the magnetic field is present and is being cut by the winding
of the coil, a voltage WILL appear across the coil, as will some
residual heating effects. The regulator can isolate this from the
battery but that only addresses the output-side of the equation.

That's a guess of course -- we're using different components. But in
a permanent-magnet type dynamo the Field is always 'on' so to speak --
there is no 'control' as is found in the typical generator-type dynamo
since there is no Field winding. In either case, I think your method
of installation calls for a bit more head-work.

-R.S.Hoover

Fun, goofy thread.

Actually, there is something called an electrically augmented turbocharger.
It's a turbocharger with an electric motor on the shaft connecting the
turbine and compressor ends. The idea is for the electric motor to help the
engine exhaust spin up the turbocharger reducing turbo lag. It's also used
on 2-stroke piston ported diesels to provide enough manifold pressure to
start them and idle.

However, once the engine is running and the exhaust pressure takes over from
the electric motor, there's no reason why the motor can't swich to being a
dynamo/generator. There's plenty of excess energy in the exhaust of an
engine producing 60 - 75% power to generate ample electric power. I once
pitched this idea to the DeltaHawk folks as a way to dump the heavy roots
blower and alternator and get a quick response turbocharger.

Of course, if your engine doesn't need a turbocharger in the first place,
just replace the compressor end with a high RPM alternator.

Fun thinking about this stuff.

Bill D

RST Engineering wrote:

This may seem like a stupid idea, but good ideas sometimes come in stupid
clothes. In a normal air-cooled tractor engine, cold air comes in the
front, passes over and through the cylinders, and is exhausted through the
plenum chamber called the bottom of the cowl. Rapidly moving air, that
after it does it cooling job, is no longer of any use.

Remember back in dem halcyon days of the 50s and 60s we sometimes mounted
inefficient little generators on small pylons on the bottom of the airframe
and called them wind driven generators (the electrical equivalent of the
side-mounted venturi tube)?

I'm just wondering if anybody has used either this scrap dump air to run a
wind driven generator, or whether any one of a number of ways of generating
electricity from heat has been attempted to convert waste exhaust gas into
excited little electrons? SOrt of a turbogenerator, if you will.

Jim


The reason the air comes out the bottome of the cowling is because there
is a low pressure area there to pull it out.

Putting something in the way to hinder that flow might be counter
productive.


--

Richard

(remove the X to email)

wrote:
On Aug 2, 11:17 pm, Ernest Christley wrote:

I need to verify, but I'm fairly certain that the reg/rec I'm using is a
switching type. It turns off the line when the power isn't needed.
Saving the generator from producing heat in both the rotor/stator and
generator.

-----------------------------------------------------------------------------------------

Dear Ernest,

I'm afraid that only addresses the power OUTPUT, not generation. So
long as the magnetic field is present and is being cut by the winding
of the coil, a voltage WILL appear across the coil, as will some
residual heating effects. The regulator can isolate this from the
battery but that only addresses the output-side of the equation.


Yes, it does keep producing a voltage, and possibly an extremely high
one at that; but heat comes from work, and a voltage is only half of
that equation. You need to move some AMPS with that voltage to heat
things up. The magnets will push the electrons as hard as they can be
pushed, but the switching regulator has opened the circuit. The
electrons bang into a wall, all jumbled together at the end of the wire.
Once the magnet passes, the little guys will relax and spread out a
bit until the next magnet comes along to push them all up against the
wall again. Thus, there is some current flow, but it is AC and in the
milliamp range.

It's easy enough to test. Run one with no load for a while. That
includes taking the regulator out of the circuit. Those older style
regulators worked by acting like a fat resistor to dump excess power,
making sure that the generator ran at full load all the time. Dollars
to donuts (yeah, I know, not a great deal anymore) that the generator
will be cooler than most of the other engine parts.

Now, put a headlamp on as a load, and run it again. You'll need the
regulator this time. You could even run it with just your regulator
(but, that's hard on the regulator). I bet another dollar that the
generator heats right up. Probably warm enough to cook that donut.

That's a guess of course -- we're using different components. But in
a permanent-magnet type dynamo the Field is always 'on' so to speak --
there is no 'control' as is found in the typical generator-type dynamo
since there is no Field winding. In either case, I think your method
of installation calls for a bit more head-work.

-R.S.Hoover

A critical piece that doesn't really come across in the pictures is that
there is a very strong air stream passing over and around the generator.
In fact, the final goal is for it to be on the inside of a centrifugal
blower. The one thing I do have left to do is to add a splash guard that
will keep debris from filling up the rotor over time, but that will be
simple enough to do.

I went out to take this picture. Used the Gimp to highlight the air
intake areas that will provide cooling air. The pattern continues all
the way around the gearbox.

http://ernest.isa-geek.org/Delta/Pic...AndCooling.jpg