WindGen-Zen
Connect a Wind Switch.
When there's no wind, you don't want the
blade spinning. These are permanent magnet DC motors and will drain your
battery. You need to DISCONNECT the generator from the battery.
This involves switches and the various diagrams below gain in complexity:
all the way up to an AUTOMATIC WIND SWITCH with a MANUAL
OVERRIDE, an ON/OFF-LOCK switch and a REVERSE/BRAKE switch.
Overview
Here's a good resource for simple switches and
although they aren't marine grade (will corrode or may cause a spark/ignition
in a bilge etc.), you may find they work well outside in a sealed area or
seal the entire switch with rubber; do it yourself and save!
Here's another one!
A switch is required or the battery will drain.
There are three basic ways to disconnect the
unit from the battery.
- You can buy an expensive DIODE that can handle 20 - 50 amps.
You can find them for $10.00 at some surplus warehouses (good luck) or
pay full pop; $50-$100 or more which really bites if you burn one up.
They also use a little power while running, so I prefer a wind switch.
A diode is the easiest solution.
The following quote came from a wind generator forum regarding diodes:
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'I got a surprise, the other day, when I dismantled an old rectifier
and typed the numbers into Google to get a spec sheet. What a
surprise to discover that these diodes had a forward voltage drop of
about 1.6 volts.
In a rectifier the current usually has to pass through two diodes in
series - one on the postive and one on the negative leg of the
circuit. Thus the combined forward volt drop is about 1.4 or more
volts for silicon diodes. Internal resistance is also a factor if
the diodes are on high load.' |
- WIND SWITCH 101:
This is what I use because there is no voltage drop.
A Wind Switch is easy to make
dependable and durable.
- Take an old marine float switch and remove it
from it's little stand (if you can) and screw it to the end of as 15 inch
long, 1/2 inch PVC pipe: this is the top of the switch. When the pipe is vertical
the switch should be off. As soon as the pipe leans about 10-20 degrees,
the float switch should turn on and allow current to pass through it.
The wires may seem a little small and in fact if they are corroded they
will cook (personal experience) and could burn your mizzen sail (and boat)
to a crisp. Keep them short, but long enough and unhindered
so the switch will swing freely. I have passed 60 knot storms through these,
BUT you will probably want to install a manual switch (below) using a
heavier guage wire for those conditions.
- On the other end get some insulating foam to act as a big wind flap. I
cut mine about 4 inches wide by 10 inches tall and adjusted the counterbalance
with screws stuck into the foam.
- Find the balance point and drill a hole just above that, towards the end
with float switch. This will hang on a piece of metal rod. I weld, so I used welding
rod for years until I got a bit of stainless. You want the foam end slightly
heavy in the balance so the pipe just about stands vertically. As long as the
switch is off when upright on the rod, you're ok.
- If you need to add a few nails or screws to make either end heavier and fine tune the balance, just stick them in the foam.
Will it weather a 72 knot storm? So far mine has weathered THREE YEARS worth
of them and costs less than $10.00 to replace.
This system will simply disconnect the battery
from the wind gen depending on the wind speed. The mercury switch (float switch)
will handle amps that a PUMP will draw and will handle what your generator
puts out in normal conditions. During the first year I used only this switch
and in 60 knots storms the wires got hot (in freezing rain) so I added
the manual switch for days when I KNOW the wind won't be under 20 knots
all day long. BUT there are times in the morning when I have walked (rowed)
away from my boat with the manual switch engaged and came back real late at night
to find NO WIND so my batteries were spinning the blade for hours and ate up
a lot of the charge for that day: too bad! The moral of this story is either
use the DIODE (I hate extra electronics) or build a dependable wind switch
and use it. Mine has never failed me.
Sometimes you want to LOCK the blades
so they won't spin no matter what: such as a storm with hurricane winds!
Use the DOUBLE THROW/DOUBLE POLE switch circuit to do that.
With this method, you can shut it off/stop the blades from spinning if the
wind gets too high. You accomplish this BRAKE by shorting the positive
and negative poles together (OFF POSITION IN DIAGRAM) which drains the
battery a bit for about 5 seconds while the blades stop.
After that you will see them idle slowly in the wind: it doesn't drain the battery or
heat the wires. It just stops the blades from picking up speed.
Sometimes you want to STOP the Blades.
With 70 knot winds screaming outside,
the blades only turn about 30 RPM in those conditions with the OFF switch
engaged (about once every two seconds...very slowly). Use the first circuit
above and then add to it below as needed:
BIG STORMS DEMAND BIG SWITCHES AND TOUGH MEASURES!
I used to use just the DOUBLE THROW/DOUBLE POLE switch and tried to turn it OFF at
the height of a 70 knot of Pacific Storm and it KEPT SPINNING?!?! Bad news!
I had to pull the wind generator off the battery (without a load on her, she really screams)
and I REVERSED the wires to get her to slow down and start spinning backwards. Then I
quickly put the wires back and threw the OFF switch: that worked. WHEW!!!
That was almost as hairy as the first winter I ran these and had NO switches
on it, no way to brake it or turn it off and during a 62 knot winter storm I had
to swing a halyard style generator into a shroud to destroy the blade (I have
since learned to use rope) and I heard a piece of a blade scream past me
going 'Phtttt' at 500 mph, maybe faster!
After such joyous evenings I now make sure I can shut it
all down no matter what is going on.
So I added another switch to REVERSE
the poles for a few seconds during intense storms (that always stops them)
and then I switch it to OFF/LOCK (ground to positive).
Sometimes you want to REVERSE the Blades.
NOTE: When setting the generator to REVERSE, set the ON/OFF-LOCK
switch to ON or it won't reverse the blades.
What are you going to do if a seagull (or piece of
storm driven plywood) crashes into the wires on your generator and these
'electrical brakes' don't work anymore? You need to know that no matter what
you can stop the blade.|
I have seen shaft lock brakes fail: destroyed as they tried to engage.
I have seen electrical locks fail...
and I have held onto the lower halyard of
an Out of control, 65 knot blowin, 4 foot blade,
'Margarita Mixer (with slice of sailor)'.
The only thing that works gently and with control
is rope;
...preferably your worst halyard.
If not, it will be once you use it for this. |
Brushes burn out every few years (or faster
if you have lot's of wind!!! YAHOOO!!!!
Check them before winter. Check them before storms, check your rig
often: it can destroy property or kill someone if you don't and
know how to take a generator apart and put new brushes in it.
Some firms sell generators (alternators with diodes etc.) with
neodimium magnets and even those withno brushes to replace! Great!
These are more efficient (more watts) and usually
more expensive. Learn to check and replace your brushes,
tighten your clamps, check your halyards and mast mounts frequently
and keep your rig and propeller safe:
YOUR ARTWORK!
It's part of the 'joy and responsibility' of being a pilot,
a sailor, a wood carver or a perfectionist with a meter.
Wire guage? Welding cable is best;
something with a single strand for positive, that's as round as your
thumb or forefinger. You can safely run that 50-100 feet but
remember longer wires lose wattage and become very inefficient.
Thinner wires can get hot and burst into flames and burn down
homes, boats, cabins and neighbors: be careful. Using extension
cords is a waste of time because so much is lost over runs of
10 feet or more. Dock Cord (50amp/220v) is adequate and won't burn
up but has some resistence over long runs. The fatter the better.
Where is the VOLTAGE regulator?
Ooooops! Sorry! I forgot...to tell ya' there isn't one!
If you are living off wind power it is a rare and blessed day that
your batteries are fully charged. If they are use this circuit
to power a refrigerator, water maker or heater, lights or radios (lot's of
things suck power). Anything with a bigger motor than the wind gen will
do as long as the motor is made for continuous duty.
Sometimes you want to BURN OFF Power.
Usually once or twice each winter and once in
the spring, all batteries are fully charged; the rest of the time
I let nature fill them by charging one or two batteries (one bank
of four 6 volt golf carts) and then switch to the other bank
when the first one is 'equalized'.
Using Golf Cart Batteries.
That's the theory behind most
'desulfating' devices; I'll include a diagram for the capacitor that
vibrates the charge when I get that installed too!
To desulfate plates, I simply use a Wind Generator attached
to each individual 6 volt battery on a windy day and watch the water
level and temperature.
Unattended, this can also burn the place so it's not for everyone,
but it does keep the batteries in good shape.
Motors: KEEP IT SIMPLE STUPID - KISS!
There are two models to get from Ametek: the green one is more
common and is a refurbed TAPE DRIVE MOTOR, available from many
surplus supply houses. Make sure you get the 72 volt model
although I am doing some experimenting with a 36 volt model but
I did this before and wasn't too happy with it.
The reason you want such a high voltage is that it is rated for
that at 1850 rpm and blades don't spin up that high: usually
300-600 rpm and only in high winds will they approach 1000 rpms.
That means at 300 the voltage is about 1/6th of 72 or 12 volts:
lower than that (200 rpm) would only be 8 volts and that means
the batteries are DRIVING the motor so in light winds the low
voltage motors don't cut it. By the way; the battery knocks the
voltage down to 12 as it comes in.
Make sure the ametek motor you get has the following
characteristics: 4 inches in diameter, at LEAST 7 inches long.
Some are only 5 or 6 inches long and those are weak unless you
are using a 4 foot blade. Finally MAKE ABSOLUTELY SURE they
have a 5/8 shaft. The 1/2 inch shaft is for a WEAKER MOTOR, less
WATTS/AMPS etc.
Now onward: I found the BLACK MOTOR (9 inches by 4 inches)
recently and hopefully it will work out. It should have a bit
more output than the green cans and if so I am going to TRY to
carve/balance an 8 footer: a record for me.
Basically you want to try to find the BIGGEST, HIGHEST VOLTAGE,
LOWEST RPM motor you can and the ameteks are the most common.
They must be Permanent Magnet DC motors to work as generators.
Don't even think about alternators; been there, worthless. The
fields take too much power to light up and they don't even break
even until winds get to about 30-40 knots and they start to hit
1000 rpm (about what a car idles at)...and even then don't put
out jack. Gearing or belts burns up too much in friction, so you
need a PM DC motor. There are sites about building custom
generators, epoxy and brake drums (very powerful) and the NASA
guy explained all the ones HE built and told me over and over (I
kept asking 'HOW DO YOU DO IT?!?')...
He said 'FORGET IT!' They ARE bigger, they DO put out more power,
but they are way too heavy for sailboat rigging (my application)
and they FAIL more often unless you are an expert at making motors,
and they are a pain to maintain, expensive to put together and dollar for dollar, the way I am
doing it (according to my Teacher) is the best way....that
includes the simple blade design.
YES, 3 blades are more efficient, a bit quieter, and all that...
but hey, I want to get power and get back on the web, NOT spend
all day (?week?) making the darn things.
YES, a computer designed carbon fiber 6 foot blade would
outperform a Doug Fir blade. YES there are curves you can add to
get a little more efficiency. YES you can even add a cowling
(behind it) to increase efficiency and output... and all of this
adds complexity to a very simple principle. If you need more
power, just build more wind gens. That is the basic theory of
the NASA guy and he's been doing this for 20 years. I listen and
gave up on the 'epoxy my own magnets and build a bigger generator
etc.' stuff. If you are inclined to do the work, great!
I have better (well, more fun anyway) things to do than
re-inventing PM motors and I hate working with epoxy.
Here are various photos and circuits for desulfating batteries, building voltage
regulators, generators to produce 110 volts and using used motors
to produce AC from a wind generator.
(click on the image to go to the advanced electrical page)
Here are wiring suggestions for using AC motors for use with wind generators:
WARNING: the circuits shown below and at
ALL other locations and pages are drawn by KCK and many
have been tested and many have not. You build these at your own
risk and understand that many UL safety issues are not included
in home-made circuits. Builder beware; a flaming circuit
can kill people and destroy property. Be safe and keep a
fire extinguisher nearby whenever you are experimenting or
running newly built circuits, and check them again when winds
are higher.
Using an AC MOTOR to charge batteries
Here is the basic discussion on this rig from an electrical
engineer:
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Using the TOP circuits above, any "motor" capacitor identified as
'run' capacitors will work. The exact capacitance value depends
on the motor and current and is probably best found by
experimentation. As a rule of thumb with a normal 120vac motor
and load, you need three 20-50 microfarad 240vac capacitors per
horsepower.
The capacitors are carrying current, and so run
warm. The little plastic case capacitors as shown would work, but will probably
also run quite hot. Most of the capacitors used for this
sort of application have a metal can and are oil-filled; they dissipate
heat much better.
To get it started, you need to to 'backfeed' the DC + 12 to the coils for a
moment; that is what you need to do. Just one pulse
of DC thru any coil in
the motor will momentarily magnetize it. This
"gets it running", like
starting a gasoline engine. Once running, it
keeps running.
The easiest arrangement is a 2-pole pushbutton
that shorts across TWO of
the diodes. The TOP schematic above only shorts one. Add a
second set of contacts (see green lines/switch added)
to the pushbutton that shorts the bottom-left
diode at the same time.
When the button is pushed, DC current flows from
battery+ thru the top right pushbutton, thru two of the motor windings
in series, thru the
left pushbutton, and back to the negative
of the battery.
Another correction to the TOP diagram above: you need 3 capacitors,
not 2. The third capacitor connects between the left and right
motor wires. The current rating of the (1.1 amps) still applies,
so the most battery charging you can get is about 1.1 amps
continuous. Probably up to 2 amps peak. The voltage is
proportional to rpm. If this motor is 1750 rpm at 460vac, it
will produce 46vac at 175 rpm, or 12v at 45 rpm. That's pretty
slow! For a 12v battery, a 12-24vac motor would have been
better.
There's an alternative (see BOTTOM CIRCUIT); you can connect the 3 capacitors in
SERIES with each of the motor's 3 phase leads. Use the other
ends of these capacitors to go to your diode bridge. This
converts it from a Voltage generator to a Current generator.
With that circuit you can spin the motor as fast as you want,
and it just generates a battery charging current proportional to
rpm (instead of a voltage proportional to rpm). In this case,
the capacitor value sets the charging CURRENT. (see redrawn
BOTTOM circuit).
Since the motor windings are only rated for 1.1 amps, you don't
need those huge bridge rectifier, just little 1N4004 1 amp
diodes will work. Each diode only conducts for less than half
the time, so a 1 amp diode works fine.
Lee A. Hart
If you would not be forgotten
When your body's dead and rotten
Then write of great deeds worth the reading
Or do the great deeds worth repeating
-- Ben Franklin, Poor Richard's Almanac
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Using all that I learned from Lee, I think I got
the following diagram a bit closer:
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