Notes:
- If you want to host any of this material please use a link to this website. TNX.
- This website was laid out using FireFox as the browser with the monitor set for 1280 x 1024. Column positions etc may vary when using other browsers or different monitor settings.
 Motor running inside of
house on solar cell
Select from the lists below.
Other articles
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Introduction:
While
many
of us have played with magnets as kids (young and old) we most likely
never could
find much to really do with them.
We immediately noticed that if you have two magnets things got more interesting. Attraction and repulsion of the north and south poles of the magnets being most noticeable. But we usually still didn't figure out a use for that feature. Moving one magnet with the other one under the kitchen table was fun though. I decided to experiment with this type of electric motor as a learning experience with really low input power motors. My record right now is 0.6 volt supply voltage with 0.177 milliwatts input power with the motor on the left. No trickery, just careful design design of the drive circuitry. There are many enthusiasts building small magnetically levitated motors. You can find videos of these motors on YouTube. The following link is to a "Mendocino" motor which uses rotating solar cells to power a magnetically levitated rotor shaft. The basic layout uses a stationary magnetic field with rotating coils on the armature. Solar cells rotate with the coils and do the commutating of the drive voltage. While these motors are unique they do operate on well founded principles. http://www.youtube.com/watch?v=Ncx2eVpWUzw&feature=related Another class of home built motors are "pulsed" motors which rotate the armature with a stationary drive coil. Various methods are used to time when the coil is energized to keep the rotor shaft running. Many use the rotating magnets themselves to trigger the solenoid drive circuitry as a blocking oscillator. Again, all these motors are based on electrical design knowledge that has been developed since 1832. The picture on the left shows a motor that I built using many common parts from my pre-owned collection of parts. The metal 1/4" x 20 threaded bolt is being levitated by neodymium magnets at each end of the bolt. In other words, the affect of magnetic repulsion is supporting the rotating parts in mid air. The motor is running in the picture while being powered by a garden night light solar cell. The motor and solar cell were inside my house on an overcast day at the time! The solar cell was located just to the right when the picture was taken |
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Purpose of
this site:
The purpose of this
site is to present the theory of how a levitated pulse motor works and
describe how you can build one for
yourself. I've learned quite a bit about building a stable
levitating system and will I explain what I've learned in the "Magnet
theory & rotor construction" article.
I also will [hopefully] debunk the over-unity claims that some people make for these motors when used to charge batteries. You will NOT discover how to make a perpetual motion machine here or anywhere else I suspect. But these motors are a great learning experience and will give you a good hands on understanding of practical electronics and magnets. I will NOT attempt to teach you electronics as there are many sites that can be Googled that go into electrical theory and design. Radio Amateur sites are a good source of common electrical designs. Most have schematics and some have construction articles. This website has hundreds of circuits with explainations etc that you might find interesting, Talking Electronics There is a lot of good information there. Resistor color codes, how the circuits work etc. If I present some formulas or terms you aren't familiar with please use that as a reason to use Google to find out what they mean. The math I use will be very basic to electrical design to keep the site geared toward non-professional experimenters. If you aren't familiar with building one of these motors I'd read all the articles presented here several times until you really understand what it's all about. Return to top of page |
| Quick review of what I've done so far: At
first I
built a crude levitating system using some low power ring magnets I had
in my extensive electronics parts pile using a ball point pen and an
aluminum TV antenna tube for the levitated part. After that
big
accomplishment I ordered a stack of twenty N42, 1/2" x 1/4" - 1/8"
thick neodymium
ring
magnets
from eBay which evolved into the motor at the top of the page.
At first I didn't want to wind a many turn coil so I searched around in my pile again and found a normal car relay which has a solenoid coil that was designed to operate on the 12 volt DC car battery system. The coil has a resistance of 150 ohms and worked better than several other coils I tried. At first I just pulsed the coil with a square wave function generator set to 24 Hz. I usually set the generator to 2 volts or less output. The generator has a 50 ohm output impedance so driving the 150 ohm coil was no problem. I then built a simple transistor drive circuit that is common on YouTube and got the motor running with the relay solenoid. The motor would not run below ~1.5 Vdc input which is commonly used. The circuit took more milliamperes to run at that voltage than I would have liked. But using a relay solenoid is a quick way to get a motor to run though. I finally found the specifications for a home made solenoid drive coil while watching this YouTube video posted by Lidmotor. He has some good videos on YouTube. No b.s. Just straight talk of what he's done. Thanks Lidmotor. I have an article here explaining the details of the coil I made. I did not end up exactly using the common circuits on YouTube since I wanted my motor to run on very low voltage and current. Basically I just biased the transistor differently to reduce the running current. Two other things I want to investigate is a simple circuit to make the motor self starting and a way [hopefully] to eliminate the vertical wall that the rotor bearing touches. That is not an easy thing to do without a lot more circuitry and not drawing more power at the same time. |
