VITA TECHNICAL BULLETIN
1-kW RIVER GENERATOR
by MATHEW G. BOISSEVAIN
The plan presented here is a detailed description of a
1-kilowatt (1-kW) generator unit, which was prepared in
The plan is scheduled to be revised and updated in the near
future in order to incorporate additional data.
At the time,
this plan was prepared, the generator had not been built on
scale shown here.
Therefore, until such time as testing results
can be integrated into the plan, VITA offers this material
an idea paper.
By way of background, the designer of the 1-kW river
made the following assumption in his calculations:
for each of the three "V"-belt speed-up
stages so that
enough power is available to operate the
unit at 4.7
ft/sec water velocity. It will
at 6.0 ft/sec.
Mathew G. Boissevain is a design engineer at a major U.S.
his many years as a VITA Volunteer, he has
developed several types of water wheels for powering water
pumps and has worked for almost 20 years designing machines
used in automated processes--for example, artificial kidney
equipment, circular weaving loom, various mail-sorting
Please send testing results, comments, suggestions, and
requests for further information to:
1600 Wilson Boulevard, Suite 500
Arlington, Virginia 22209 USA
Tel: 703/276-1800 * Fax:
VITA Technical Bulletins offer
technology information on a
variety of subjects.
Bulletins are idea generators
intended not so much to provide a definitive
answer as to guide the user's
thinking and planning. Premises
and testing results are provided,
Evaluations and comments based on each
experience are requested. Results
incorporated into subsequent editions,
providing additional guidelines
adaptation and use in a
variety of conditions.
1-kW RIVER GENERATOR
WHAT IT IS
The river generator uses the flow of river water to produce
1-kW of electrical power.
It has four 5-ft diameter propellers
attached to a log float.
The float is anchored to the river
From actual trials with 40" propellers, it is
water flowing at 4.7 to 6.0 ft/sec will turn the 5-ft
with enough power to generate 1000 watts of electricity.
The propellers are connected to the generator by a series of
"V"-belt pulley drives that speed up the slow 66-revolutions
per minute (rpm) of the propellers to the fast 3600-rpm of
A variable speed pulley at the generator and a built-in volt
meter will enable the user to adjust the generator rpm and
voltage for varying river flow and generator load
Most of the pulleys, shafts, and "V"-belts are
simplifies building and reduces spare parts needed.
Due to slow speeds (except at the last stage) the unit
last a long time, if built as instructed.
It does not need
elaborate dams, river falls, or pipes, as do Most
plants. You can
build as many of these generators as
needed, spaced about 100 feet apart downstream.
a paddle wheel, under identical conditions, would need
at least as large as the entire back frame of the river
(see drawing, rear view) to provide the same amount of
power. Also, it
would only turn at about 5-7 rpm and would need
more speed-up stages of "V"-belts.
The 1-kW river generator will produce about 720-kW hours per
month, which should be enough energy to run a simple
Some effort must be made to conserve energy, and to spread
energy use as evenly through the day as possible.
WHAT YOU NEED TO BUILD ONE
This design requires access to a river that runs with a
of from 4.7 to 6.0-ft/sec year round with a depth of at
6-ft over a 21-ft width.
This principle will also work on a
smaller scale with a corresponding reduction in power
If you have access to a waterfall or higher water speeds,
could make a 1-kW or bigger unit with smaller (but stronger)
propellers, turning at higher speeds, and with fewer pulleys
and belts. These
higher speeds can also be obtained by building
Purchased parts (see parts list) total US$612.81, based on
list prices in the United States.
To this, you must add tax and
shipping and the cost of all lumber and logs used.
cost, you may be able to find your own parts (airplane
large fans, washing machine pulleys, etc.).
prices may have changed drastically since 1971, be sure it
economically feasible before you begin construction.
* Wood saw
* Hammer and/or
* 1" wood drill
* 1/2" wood
* 3/16" metal
drill (for nail holes in item 21)
* Allen wrenches
(for 1/4" set screws in pulleys)
* Metal file
* Pliers to cut and
twist 1/8" wire
* Wrench for
1/4" bolts in propellers
diameter drill for increasing hole in cast iron pulley
(item 13) from
.625" diameter to .669/.673" diameter.
* 14 straight logs,
5"-8" diameter X 21' (Bamboo may also be
used instead of
logs. Use wire around joints to make
* Planks, 2" X
4"; as shown on page 9.
WHERE TO BUILD
Find a place in your river, close to home, that has a water
speed of 4.7 to 6.0-ft/sec.
This must be measured exactly.
3-ft/sec water speed, you will get only about one-fourth of
power, or 250 watts.) To measure the speed, measure off 50-feet
along the river bank and mark with sticks.
Then, count the
exact time required for the water to carry a log or branch
between the sticks.
The time must be 8.3 to 10.6 seconds.
place to build your river generator is upstream from the
chosen, so it can be launched like a large boat and
floated into place.
After the frame has been built, attach the
rope (item 20) to the pointed end and anchor the float in
place, using a boat anchor, a large rock, or a 2-inch steel
pipe driven into the river bottom.
HOW TO BUILD
spending money on parts, it may be wise to build
the log frame and test it out to make sure it holds together
under all river-flood conditions.
The author has successfully
built smaller frames than the one shown.
may arise with a larger one.
Build the frame as shown in the following drawings.
Be sure to
reinforce all the joints with metal plates (item 21).
could possibly be used here.
Remove ends, flatten, then dip in
paint to prevent rusting.) The wire (item 22) is used to
branches, etc., out of the propellers.
Also, use wire braces at
the back section (see rear view), and on all joints when
the frame with bamboo instead of logs.
Drive System. Next,
make all the wooden parts shown on the
"side view" drawing.
Items 18 and 19 should be made of hardwood.
Soak it in water after drilling the hole.
Then open up
the hole as needed until the 1-inch shaft turns
the same for item 3 (pivoting frames--to provide V-belt
tension), but soak it in oil around the hole where the shaft
goes by filling oil holes after shaft is assembled.
necessary to provide smooth running shaft.
Attach item 9 to the vertical members on the float, with the
shaft in place. Make
sure the shaft is square with the frame as
shown in the drawing.
It is important to end up with the
dimensions as shown in the "rear view" drawing,
"V"-belts are not adjustable in length.
Shafts. Attach the
pulleys to all the shafts, as shown.
or drill 1/8-inch into the shaft under all the set
prevents the pulleys from turning on the shaft.
attach with a split bushing and will grip the shaft tightly
when the bushing is bolted tightly against the propeller
Belts. Install all
propeller belts and weight down each item 3
on both sides of center with rocks, as shown.
This will provide
a constant, even tension on the belts and reduce belt wear.
Allow the belts to set in the exact position of item 12
bracing it as shown on the "rear view" drawing.
Repeat above with the tall item 12 at the center of the
After the unit is back in the water and operating under
add rocks as needed to prevent belt slippage.
Don't make the
belts too tight as this increases wear.
Adjust the variable speed pulley on the generator to get the
120-volts needed. Be
careful to ground the generator housing
and ground wire in the water, and to keep people away who
know the dangers of 120-volts of electricity and wet feet in
Insulate all exposed wire.
Follow wiring instructions that come
with the generator, and run the cable down the anchor rope,
then along the river bottom (weight with rocks) to the
Propeller Blade Tip Angle Adjustment.
At 4.7-ft/sec water
velocity, the propeller must turn at 60 to 70-rpm.
propeller tip until the blade is angled as shown below.
blades must have a 9 [degrees] angle.
W. W. Grainer, Inc., 519 Potrero, San
Francisco, California U.S.A. [Phone:
Browning Mfg. Division, Emerson Electric
Co., Maysville, Kentucky
Ryerson Steel, Box 8427, Emeryville,
California 94608 U.S.A. (also, U.S.
Durkee Atwood Co., Minneapolis, Minnesota
55413 U.S.A. [Phone: (612)
Sears, Roebuck & Co.
Los Angeles, California 90054 U.S.A.
(NOTE: Drill item 13 from
to .669" diameter.)
Where to Buy
60" exhaust fan, 1" bore
3 CO 32
14" pulley, 1" bore
3 X 944
4" pulley, 1"
"A" section "V"-belt
90.02 Durkee Atwood
F32 KF 32054 N
1" X 18" long shaft
Type 303 SS
3" door hinge
12 gauge, 5/8" bore
1 W 676 26.75
Variable pitch pulley
3 X 276
"A" section "V"-belt
10.00 Durkee Atwood
4" X 8" X .125" thick
1" flat washer
1" diameter rope
4" long nails, plated
1/8" soft galvanized steel
Total cost of all purchased parts except wood
Add tax and