Car alternator wind mill generator?

[BobG]

Do it mechanically. Build a centrifugal governor into the nose cap
(or whatever it's called), and have its output feather the blades as
needed.

=========================================
A mechanical solution would have been an excellent suggestion in the
50s or 60s before electronics. I think my idea of having the pitch be
a function of wind speed wins two ways... dont need to slow the blade
down in high wind, and it will allow power to be generated in much
lighter breezes than with a fixed pitch. Will your mechanical design
be able to adjust pitch to handle both these situations of high and
low speed wind?

 

[MooseFET]

[....]
The problem it that car alternators do not have magnets.
Any alternator that has been installed and used on a car will "build
up" if you wire it up and give it a spin. There is enough
magnetization left to overcome the rectifier's forward drop.

Not without the field coils energized. I saw a circuit once for self
energizing the coils. It's still a parasitic load.

Perhaps give the field a split second jolt from a battery, when an rpm sensor
indicates adequate speed. Use a diode, resistor, capacitor to have the output
latch it into operation. The generator would engage and drop out
automatically. Crude functioning circuitry would be cake, with lots of room to
expand sophistication.

You don't have to do that. When the rotor is going at 1000RPM you
will see a small voltage on the stator even with the rotor not hooked
up. This is enought to get the buildup started.

 

[Craig Ruff]

Anyway, the point is that three of our offices are on the sides of
mountains or very tall hills where 3/4th of the day it is *really*
windy. Since we have very little funding i was trying to think of a
cheap means of power and thought about putting together a "cheap" wind/
generator from a truck/car alternator and fan and a few car batteries.

[/QUOTE]

Check out http://www.otherpower.com/ which has all kinds of good
information about this subject. They build alternators from scratch
along with the turbine blades, etc. Various projects of this type
are documented with descriptions and lots of pictures. They describe
the issues with different methods in some detail. For wind power,
start at http://www.otherpower.com/otherpower_wind.html

 

[Craig Ruff]

Car alternators are all but useless. You need a permanent magnet
motor.

Check out http://www.otherpower.com/otherpower_wind.html for good
information about scratch built wind power systems.

 

[clare at snyder.on.ca]

=========================================
A mechanical solution would have been an excellent suggestion in the
50s or 60s before electronics. I think my idea of having the pitch be
a function of wind speed wins two ways... dont need to slow the blade
down in high wind, and it will allow power to be generated in much
lighter breezes than with a fixed pitch. Will your mechanical design
be able to adjust pitch to handle both these situations of high and
low speed wind?

Properly done, yes.

 

[Paul Burke]

Should be easy to let the rotor move back against a spring as the wind
pressure increases, and use that to feather the blades via a simple cam
mechanism.

 

[gearhead]

Cars used to have permanenet magnet generators

Which cars? Are you sure?

From what I know of antique vehicles with dc generators -- series-

wound, with segmented commutators -- they did not use magnets. I
speak from my experience with antique Harleys and GM trucks.
The only vehicles I know use magnets are motorcycles, and they use
them in alternators, not dc generators. I've seen old British bikes
and late model Harleys like that.
The old dc generators had pole shoes made of soft iron with enough
magnetic remanence to get them started back up again, without the use
of magnets. Same thing MooseFet has been saying about alternators --
they will start up without feeding the field. With alternators, you
may have to spin them up to make it happen.
Fact: lots of people use their alternators in something called a "one-
wire" setup. This means there is no "tickler" current from the
battery to feed the field. Depending on the vehicle, this may mean
that starting the car into an idle will not get the alternator started
charging. You have to gun the engine, if sitting, or just drive it,
which will get the rpm's up to where the field gets over that hump to
where it can feed itself.
For the original poster:
the two drawbacks of car alternators re windpower that I've hear of
(not speaking from experience) are the spindly little bearing, and the
extra I squared R losses in the field (rotor).
If you ever took apart a car alternator, you would see what I mean
about the bearing, really dinky. In particular, it is not a thrust
bearing.
People use wheel bearings instead, when they build their own.
Magnitudes more robust.

 

[Arnold Walker]

=========================================
A mechanical solution would have been an excellent suggestion in the
50s or 60s before electronics. I think my idea of having the pitch be
a function of wind speed wins two ways... dont need to slow the blade
down in high wind, and it will allow power to be generated in much
lighter breezes than with a fixed pitch. Will your mechanical design
be able to adjust pitch to handle both these situations of high and
low speed wind?

Constant velicity props are old hat not only will they feather ,but like on
the C130 they actually will reverve.
Pilot do that for short runways.

 

[Arnold Walker]

Should be easy to let the rotor move back against a spring as the wind
pressure increases, and use that to feather the blades via a simple cam
mechanism.

Dependents on rotor or prop size ....Hamilton Standard used hydralics to do
that.Would change pitch fast enorgh to govern turbine engines on a C130 and
more than a few light piston aircraft .

 

[Arnold Walker]

I am presently working for an NGO in Afghanistan and some of our feild
offices are waaaaaay out in the boonies (no electricity, no running
water, nada). At the moment they have a cr*ppy chinese generator and
funding is apparently so tight that we can't afford another generator
(since the chinese generators have proven to have a life of about a
year and the higher ups don't seem to have a concept of spending more
money for a better generator [like a Honda generator]).

Anyway, the point is that three of our offices are on the sides of
mountains or very tall hills where 3/4th of the day it is *really*
windy. Since we have very little funding i was trying to think of a
cheap means of power and thought about putting together a "cheap" wind/
generator from a truck/car alternator and fan and a few car batteries.
The problem is, my background is agricultural development so i have
little concept of if the afore mentioned setup would even work or how
much it would power or how much it would cost. The most power our
offices use is to power a TV or Computer plus flourecnet lights and
thats it. I have looked around on the internet for plans for cheap
solar or wind power setups but haven't found many (I am told they are
there, but the ones i have found seem to be insanely complicated or
way too expensive).

So if anyone out there knows of such plans or NGOs that deal with such
things (I tried geek corps but it appears that was a bit low tech for
them) please let me know!

Here's one place you can go for homebrewed systems of all types:
http://www.homepower.com/

Note: Even at a do-it-yourself level, these systems aren't going to be
cheap. If you can't afford a decent Honda generator, this won't be easy.

The propellor design is somewhat critical if you want any sort of
efficiency. Just any old fan won't do

Actually ,I was talking about the DC motor on the fan since there seem to
interest in a punky
sized generator .

 

[Paul Hovnanian P.E.]

======================================
The model plane guys have variable pitch props now. Instead of
fretting about the thing blowing apart from centrifigual force in a
big wind, just feather the prop. A $5 microcontroller and a gearhead
motor could modulate the blade pitch to control the torque and speed
under varying wind profiles. Work smarter not harder. Technology.

Two issues here: Horsepower (the windmill involves much higher forces
than any model airplane) and cost. The OP stated that a decent (i.e.
Honda) generator might be beyond their means. This pretty much rules out
anything but the simplest rig.

One other thing I just thought of was something like the windmill
battery chargers people use on sail boats. Although these units aren't
cheap (nothing on a boat is :-|), one can use their design as a start.

 

[clare at snyder.on.ca]

Which cars? Are you sure?
wound, with segmented commutators -- they did not use magnets. I
speak from my experience with antique Harleys and GM trucks.
The only vehicles I know use magnets are motorcycles, and they use
them in alternators, not dc generators. I've seen old British bikes
and late model Harleys like that.
The old dc generators had pole shoes made of soft iron with enough
magnetic remanence to get them started back up again, without the use
of magnets. Same thing MooseFet has been saying about alternators --
they will start up without feeding the field. With alternators, you
may have to spin them up to make it happen.
Fact: lots of people use their alternators in something called a "one-
wire" setup. This means there is no "tickler" current from the
battery to feed the field. Depending on the vehicle, this may mean
that starting the car into an idle will not get the alternator started
charging. You have to gun the engine, if sitting, or just drive it,
which will get the rpm's up to where the field gets over that hump to
where it can feed itself.
For the original poster:
the two drawbacks of car alternators re windpower that I've hear of
(not speaking from experience) are the spindly little bearing, and the
extra I squared R losses in the field (rotor).
If you ever took apart a car alternator, you would see what I mean
about the bearing, really dinky. In particular, it is not a thrust
bearing.
People use wheel bearings instead, when they build their own.
Magnitudes more robust.

The major inefficiencies stem not just from the copper losses in the
rotor, but the large air gaps and the "iron losses" involved in the AC
stator cores.

Yes, the bearings are dinky = but not a problem at all when belt
driven like in the car, or when coupled to a co-axially mounted and
independently supported blade.

 

[Arnold Walker]

Which cars? Are you sure?
wound, with segmented commutators -- they did not use magnets. I
speak from my experience with antique Harleys and GM trucks.
The only vehicles I know use magnets are motorcycles, and they use
them in alternators, not dc generators. I've seen old British bikes
and late model Harleys like that.
The old dc generators had pole shoes made of soft iron with enough
magnetic remanence to get them started back up again, without the use
of magnets. Same thing MooseFet has been saying about alternators --
they will start up without feeding the field. With alternators, you
may have to spin them up to make it happen.
Fact: lots of people use their alternators in something called a "one-
wire" setup. This means there is no "tickler" current from the
battery to feed the field. Depending on the vehicle, this may mean
that starting the car into an idle will not get the alternator started
charging. You have to gun the engine, if sitting, or just drive it,
which will get the rpm's up to where the field gets over that hump to
where it can feed itself.
For the original poster:
the two drawbacks of car alternators re windpower that I've hear of
(not speaking from experience) are the spindly little bearing, and the
extra I squared R losses in the field (rotor).
If you ever took apart a car alternator, you would see what I mean
about the bearing, really dinky. In particular, it is not a thrust
bearing.
People use wheel bearings instead, when they build their own.
Magnitudes more robust.

Or they have the mechical ability to know what a jack shaft is using pillar
bearings.
And maybe a flywheel ringgear in a wet sump for a drive off the shaft.to the
alternator(s).
Maybe a excitor control to load the the blades when it overspeeds.
So the blades can start with little load ,then at a given voltage adjusts
the exciter to maintain constant speed with varying torque.
Given that alternators replaced generators ...not even the Honda you
mentioned is a "true"generator.(It an alternator....)
One wonders at how bad those R losses are in the net result.

As to the cars with permenent magnets ,the first cars had a magneto,
including the first GM trucks and Harleys.
The perment magnets where phrased out as stated in the 50's roughly with
alternators.
Since generators could not charge at idle and the alternators could.

 

[krw]

Ford's were bolted to a flat machined on the back end of the
alternator housing.

My '70 AMC Gremlin's VR was a vibrator type bolted on the fire-wall,
so not everyone changed in the '60s. ;-)

 

[Jim Thompson]

My '70 AMC Gremlin's VR was a vibrator type bolted on the fire-wall,
so not everyone changed in the '60s. ;-)

Gremlin? Snicker ;-)

I'd guess a '70 Gremlin would be pre-Chrysler ??

...Jim Thompson

 

[Tater]

Which cars? Are you sure?>From what I know of antique vehicles with dc generators -- series-

wound, with segmented commutators -- they did not use magnets. I
speak from my experience with antique Harleys and GM trucks.
The only vehicles I know use magnets are motorcycles, and they use

your experience needs to be corrected. yes they had commutators,
because the magnets were in the case, not the armature.

had some nice suckers in there, most autoshops pulled em out to use
for welding magnets

 

[krw]

Gremlin? Snicker ;-)

It wasn't at *all* funny (other than its looks). What a stinking
pile of dung!

I'd guess a '70 Gremlin would be pre-Chrysler ??

Yep, AMC.

 

[philkryder]

Dependents on rotor or prop size ....Hamilton Standard used hydralics to do
that.Would change pitch fast enorgh to govern turbine engines on a C130 and
more than a few light piston aircraft .

sure.
And how does this help a guy in afganistan who just wants to watch tv?

 

[clare at snyder.on.ca]

your experience needs to be corrected. yes they had commutators,
because the magnets were in the case, not the armature.

had some nice suckers in there, most autoshops pulled em out to use
for welding magnets

In north america virtually NO automotive DC generators had permanent
magnets Up untill only a few years ago, not even automotive STARTERS
had permanent magnets. Today many do. I can still remember when wiper
motors and heater motors had wound fields instead of permags.

 

[Steve Spence]

in message

In north america virtually NO automotive DC generators had permanent
magnets Up untill only a few years ago, not even automotive STARTERS
had permanent magnets. Today many do. I can still remember when wiper
motors and heater motors had wound fields instead of permags.

even the vw generators were shunt wound motors, no magnets.