Unfortunately Tom was sick therefore we did not have a presentation from him. Get well soon Tom!

But I did saw his presentation in different class (technical communication). So today I am going to blog about one of devices that he presented – Mendocino Motor.

There are many types of engine that can benefit us in our daily lives. During Tom’s presentation he introduced us 3 different types of motor that can create energy.

1. Stirling engine

2. Mendocino Motor

3. Peltier device

Mendocino Motor interested me the most. The other two engines both require the changing temperature to generate energy. Mendocino motor is using the solar panel and also the levitation from magnets that generate movement on the motor.

What is a Mendocino Motor?

The Mendocino Motor is a magnetically levitated, solar powered electric motor.  It was first made by inventor Larry Spring of Mendocino County in California, for which it is named. The motor consists of a spinning shaft that is held up by repelling magnets, stabilized by resting a point against a wall.  It is powered by solar panels mounted on the spinning shaft, which generate currents through coils of insulated wire.

 

How it works

The motor base consists of five sets of magnets. Four magnets in the base are levitation magnets which provides levitation force against the shaft magnets. The fifth magnet, is a field magnet which provides the magnetic field for the rotor. The back plate has a piece of glass as a bearing plate.

The rotor consists of a shaft with a point on one end, magnets and rotor block. On the rotor block, there are four solar cells; one cell on each of the four sides and two sets of windings.

How it works. The rotor is levitated by the repelling force between the shaft magnets and the levitation magnets on the base. The levitation magnet also provides a forward thrust to keep the shaft point against the bearing plate.
When the light strikes one of the solar cells, it generates an electric current thus energizing one of the rotor windings. The Mendocino Motor floats in its own magnetic field and converts light into electricity and magnetism, which are then converted into the motion of the motor. It provides the satisfaction of creating an amazing bit of technology, and the opportunity to explore magnetism, electromagnetism, electric motors, solar power generation, and personal manufacturing. This produce an electromagnetic field which interacts with the field magnets in the base, causing the rotor to turn. As the rotor rotates, the next solar cell comes in position, This cell now energizes the second winding. The process repeats again.

 

 

 This picture shows when the Motor is floating in the air.

 

When the solar panel getting the light it will change the magnetic field and start turning as the picture shown at the left.

 

 

In the graphic below, we change the rotating magnet into an electromagnet, represented by the classic example of wire wound around a nail.  In one region, from 45 to 135 degrees of rotation, we run current through the electromagnet in one direction.  To keep trying to rotate the spinning electromagnet in the same clockwise direction, we run current in the opposite direction in the 225 to 315 degree region.Because we run the current in opposite directions, the torque is always turning the shaft in one direction.  During the “off” periods, inertia of the spinning motor has to be enough to get it to the next “on” cycle for it to keep spinning.

 

In brushed DC motors, conductive brushes are set up to make contact from an electrical source to the coil of wire.  With brushes setup to only make contact during those times in the rotation cycle that will help it rotate, the motor will spin powered by the electric current provided.

 

Math:

Solar panels like these have a performance curve that describes what they are capable of.  On this curve is an important point called the, “characteristic resistance.”  If you hook up the panel to a resistor with that value (or some load at that resistance), you’ll get the most power from it.  Therefore we choose a length of magnet wire that had a resistance equal to that spec.We take the electricity from the panel and run it through a coil of thin magnet wire, consisting of many turns around a loop.  When sitting in a magnetic field (near a magnet), a torque can be felt in that loop of wire.  How much torque?  The maximum torque, at the angle where maximum torque is found, can be expressed as , where

• N = the number of turns of wire
• I = the current through the wire
• B = the magnetic field within the loop of wire
• A = the area of the loop

The picture shows resistance occurs right at the bend of each panel spec.  While both panels represented can offer a similar amount of power, one will offer higher currents at a lower voltage, while the second offers a much lower current but at a higher voltage.

 

 

 

 

 

 

“Mendocino Motor.” MAKE. N.p., n.d. Web. 31 Oct. 2013.<http://makezine.com/projects/make-31/mendocino-motor-2/>

“Information on the Mendocino Solar Motor.” Information on the Mendocino Solar Motor. N.p., n.d. Web. 31 Oct. 2013.<http://www.chessplayingrobot.com/id4.html>

“Sign up for Our Monthly Newsletter!” K&J Magnetics Blog. N.p., n.d. Web. 31 Oct. 2013.<http://www.kjmagnetics.com/blog.asp?p=mendocino-motor-1>