Homopolar Motor

Homopolar motor - Wikipedia, the free encyclopedia
DIY simple homopolar motor made with drywall screw, alkaline ... How to build a simple 3-part homopolar motor. Electromagnetic Rotation (the key experiments) ...
en.wikipedia.org

How to make a homopolar motor :: Dangerously Fun
Illustrated guide showing how to make a homopolar motor with just a battery, a magnet, and a piece of wire. ... Homopolar Motor ...
dangerouslyfun.com

Evil Mad Scientist Laboratories - How to make the simplest electric motor
The classic homopolar motor with the copper disk and the horseshoe magnet is ... What I made is a homopolar motor without neodymium magnet ...
www.evilmadscientist.com

Homopolar Motor - Video
... a simple motor with 3 household parts.. Watch Video about Homopolar,Motors,Magnets ... How To Make A Homopolar Motor. Favorite On: monkeypm 57vett Ndugeusi ...
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simple homopolar motor made with drywall screw, alkaline cell, wire, and neodymium disk magnet. The screw and magnet contact the bottom of the battery cell and are held up by magnetic attraction.

A homopolar motor has a magnetic field along the axis of rotation and an electric current that at some point is not parallel to the magnetic field. The name homopolar refers to the absence of polarity change.

Description Moving electric charges (an electric current) in a magnetic field experience a force that is perpendicular to both their direction of movement and the magnetic field, called the Lorentz force. In the homopolar motor shown on the right, the electric current produced by the battery moves radially through the disk magnet, which has a magnetic field along its longitudinal axis. The resulting Lorentz force in the tangential direction produces a torque in the magnet, which is free to rotate with the attached screw.

It is not necessary for the magnet to be electrically conductive, or to move. One can attach the magnet to the battery and allow the wire to rotate freely while closing the electric circuit even at the axis of rotation. Again, where at some point along the electric loop the current in the wire is not parallel to the magnetic field, there occurs a Lorentz force that is perpendicular to both. This Lorentz force is tangential and produces a torque in the wire, so that the wire rotates.

In contrast to other electrical motors, both the orientation and magnitude of the magnetic field and the electric current do not change.

Like most electro-mechanical machines a homopolar motor is reversible so that when electrical energy of a suitable kind is put into its terminals, mechanical energy can be obtained from its motion and vice versa, (see homopolar generator for details on construction and theory of operation).

History The homopolar motor was the first ever device to produce rotation from electromagnetism. It was first built and demonstrated by Michael Faraday in 1821 at the Royal Institution in London.

Sources of Confusion People are sometimes confused by the fact that there are no changes in the magnetic field or electric current, and no recognizable North-South pole interaction between the magnet and the electric circuit. People often think that line of force cannot be used to understand homopolar machines, or that the field lines rotate -- see Faraday Paradox. Others refer to special relativity to explain the homopolar motor. The homopolar motor also may seem to require a conducting magnet.

The homopolar motor can be well explained by the Faraday model of lines of force, with a tangential force (hence, a torque) resulting where the electric current makes an angle with the magnetic lines of force. The homopolar motor provides a simple demonstration of the Lorentz force.

See also

External links

How to build a simple 3-part homopolar motor
Electromagnetic Rotation (the key experiments)

Homopolar motor - Wikipedia, the free encyclopedia
A homopolar motor has a magnetic field along the axis of rotation and an electric current that at some point is not parallel to the magnetic field.

YouTube - 3 Part Homopolar Motor
A simple electric motor made from only a battery, a magnet, and a wire. Details: http://dangerouslyfun.com/

YouTube - Homopolar motor demonstration
Read more athttp://www.evilmadscientist.com/article.php/HomopolarMotor ... Choose which country's videos, channels, and activity filters (for example, "Most Viewed"), you would ...

Grand Illusions - Articles - Homopolar Motor
Here is a small challenge - to construct an electric motor from the parts shown above; a battery, a piece of wire, a screw and a neodymium magnet.

Homopolar Motor - Video
How to make a simple motor with 3 household parts. ... 00:07. Homopolar Motor -... 14-Nov-06 Rated 4.14 | 9,423 Views | 3 Comments

Homopolar Motor - Video
N/A Watch Homopolar Motor Video at Metacafe ... 00:54. Battery Magnet Wi... 26-Mar-07 Rated 4.16 | 9,180 Views | 6 Comments | Producer Rewards: Candidate

How to make a homopolar motor :: Dangerously Fun
Illustrated guide showing how to make a homopolar motor with just a battery, a magnet, and a piece of wire.

Evil Mad Scientist Laboratories - How to make the simplest electric ...
... Volume 1, the Howtoons comic shows how to make an electric motor that works that way. None of these is really the simplest motor. The real champion is the homopolar motor.

A simple homopolar motor
A motor with only a battery, wire, and magnets. ... When I did this I just got the magnets from those stacking magnet toys. Soaked them in acetone for a while and they fell out.

Low Voltage Power
Homopolar motor 2006 This is one simple motor and fast to make. Really only took minutes to make it run. Running here at 5800 RPM. It ran for 2:35 minutes once the power is off ...