Freqently
Asked Questions
Where
can I get the rare earth magnets?
Here is the information for ordering
magnets from Lee Valley Tools. You can order the magnets
and have them shipped to you.
phone: 1-800-267-8767
fax: 1-800-668-1807
Web site: www.leevalley.com
To view magnet information go to: http://www.leevalley.com/wood/page.aspx?c=1&p=32065&cat=1,42363,42348
The product number and information is as follows:
99K32.11 outside diameter 3/4”, thickness 1/8” - One container
has 5 magnets. Purchase three + packages the price is reduced to $6.60/ container.
We have also used the 1” magnets often but there are very powerful and
are harder for the students to pull apart. They are also more expensive than
the 3/4”. Part number is 99K32.13 1” outside diameter and 1/8” thickness.
Purchase three + packages the price is reduced to $9.95/ container.
My
wind turbine or water wheel does not make electricity.
What should I check?
Check the following!
- Do you have a bad wire connection?
(more info below)
- Did
you sand the wire connections that wrap around the LED
light?
They
should
be "silver" at the end.
- Are your magnets close to the coils?
Are they too far away? (more info below)
- Are your magnets pointing in the
same direction? (more info below)
A
bad wire connection
In this case, resistance is indeed futile! If you have a
bad connection somewhere between the coils. Depending on
the
gage of wire you've used (assuming you've got 24 gage),
your total resistance across all 4 coils should not be more
than
about 10 ohms. Disconnect the coils and reconnect, testing
each connection before going on to the next.
With this set-up, you should easily obtain 1.5 volts, more
than enough to light up an LED.
Magnet orientation
Turn two of the magnets over so that all four are either
north or south, and flip two of the coils over so that
they are all
one orientation (either clockwise or counterclockwise. It's
easy to get the magnets right, but much trickier to get the
coils right. You have to imagine the coils as if they were
sections of a single extremely long garden hose that was
laid out in 4 connected coils on the lawn. Water entering
one end
must be able to follow a clockwise path through the first
coil, flow freely into the second coil and again take
a clockwise
path, and likewise through the last two coils. If you don't
get this right, the coils cancel each other out, and the
voltage reading will be zero, or close to it. I suspect
this to be
your main problem.
Do
I have to use a LED light?
You
have to use an
LED light Instead of an incandescent flashlight bulb. It
will illuminate
with less than one volt and very low amperage. They are inexpensive,
available at any Radio Shack store. Be sure to sand the wire
(until white) off before wrapping it around the legs of the
LED. The nice thing about LEDs is that they light up only
when the current is going one way. Therefore, they flash,
and the rate at which they flash demonstrates the speed of
the rotor, and the fact that it is producing alternating
current.
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Turbine turns too slowly,
or turns with difficulty
Probably
causes is the screw eye is too tight. Use pliers to enlarge
the screw eye, or replact it with a larger one. OR if the
pointed end of the dowel is binding in the screw. Re-sharpen
the
dowel,
or smooth
it
with sandpaper.
There
is no voltage reading on voltmeter, or readings
are erratic.
Probable causes are the magnets are too weak. Substitute
stronger magnets. Use the ultra strong rare earth magnets.
See information for Lee Valley Tools above.
The
Volt metre is set to DC or you are using a volt meter that
has
no AC
setting. Set volt meter for alternating current (AC), or
switch to a digital volt meter with AC setting.
Coils
are not oriented correctly. Recheck coil orientation. Following
the wire through the circuit, it should spiral through the
first coil in either a clockwise or counter-clockwise direction,
and should go the same direction in each of the other coils.
Poor
connection with the volt meter. Re-sand the ends of the wire
where they join the LED. Connect to the voltmeter with alligator
clips.
Gap
between magnets and coils is too large. Use the screw to
lower the height of the rotor disk to 1 mm of the coils.
Rotor
is turning too slowly. check the screw eye, fram, coils and
make sure nothing is binding or causing excessive friction.
Adjust or re-size as necessary to get the turbine to spin
freely.
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The
readings are greater then 1 VAC on the meter but the
LED does not light up.
The
LED may have too high a voltage range. Substitute an LED
that activates at 900 millivolts or less. There could also
be a bad connection on one or both of the wires. Untwist
the wire from the leads, re-sand, and twist on tightly, or
use solder.
The
magnets and / or metal washer falls off rotor
- 1)
There is a poor bond between the washer and the rotor disk.
Use rubbing alcohol or soap and water to remove grease from
the washer. Scrub the surface of the washer with sandpaper
and reglue it with a generous blob of hot glue.
- 2)
Poor adhesion between magnet and washer, caused
by a weak magnet. Substitute a stronger magnet, or add some
hot glue or instant cyanoacrylate glue to attach the magnet
permanently.
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