This activity is called homopolar motor because the electric current flows in the same direction on both segments of the wire. The worlds simplest electric motor the homopolar motor. The permanent magnet in the animation at left produces a magnetic field b that is vertically upwards through the conducting disk. How to make a homopolar motor from battery youtube. The modelling and numerical simulation of a simple homopolar motor, similar to that what has been presented by michael faraday in 1821 firstly, was used as an example. The electric motor is built from a screwdriver, battery, magnets and copper wire. This demonstration clearly shows the wire moving, so it makes matters more obvious and jives well with the technical explanation. Michael faraday demonstrated this motor concept in 1821 at the royal institution in london. The battery and magnet will create a magnetic field and the magnetic force will cause the wire to rotate. Even simpler than a basic dc motor, is a homopolar motor. Homopolar motors are the worlds simplest electric motor.
They were first invented in the 1800s and have no significant practical application today, but can be useful for the demonstration or understanding of how electrical currents and motors work. Participants learn the everyday science of electric motors in this fun and engaging workshop activity. Typical aa batteries are designed to give between and 1500 mah, or milliamp hours, meaning they can provide a steady 1 amp current for 1 to 1. Based on a modification first suggested by strickler 9, replacement of the conducting disc used in a homopolar motor with a conducting disc that produces a magnetic field of its own allows for a surprising simplification with which a homopolar motor can be built. When describing how a homopolar motor works, most explanations describe it in terms of a force acting on the wire. In this paper some simple homopolar motors employing neodymium magnets. Homopolar generators in the simple schematics below, weve made a homopolar generator by replacing the cell that drove the homopolar motor with a voltmeter. Use superstrong magnets to make a simple motor science.
A piece of reflective tape with a laser tachometer is used to measure the motors rotations. The superconducting dc homopolar motor offers many benefits, including a very small diameter and light weight. Study of homopolar dc generator a thesis submitted to the university of manchester for the degree of doctor of philosophy in the faculty of engineering and physical sciences 2012 mehdi baymani nezhad. First created in 1821, it really is the simplest example of a motor possible, and really easy to experiment with. Supply list for homopolar motor i bought the wrong magnets so i would suggest you buy this smaller one instead. Please provide good info and please no negative comments. Current is a flow of charge, namely electrons, and is measured in amperes or amps.
Performance of twinrotor dc homopolar motor semantic scholar. Michael faraday in 1821, these motors are amazing easy to build and use. In our previous blog article we took a look at how a dc and an ac motor works and described how you can build your own basic dc motor. I recommend starting with a basic homopolar mtor to get the hang of how the motor actually works, then trying your hand at making a tiny dancer. The main parts are a permanent magnet with an adjacent metal disc and shaft. Homopolar motor explained science fair projects, magnets. In this video i will show you how to make a homopolar motor from battery in one minute. A homopolar motor is a simple electric motor with two magnetic poles. Before we get started i want you to know that despite this looking very easy there is a fair amount of tweak time you will need to invest to make this project work. Electromagnetism runs the motor by being in bother electric fields and magnetic fields. Homopolar motors can be made out of a single aa or c battery, a single neodymium disc magnet and a piece of copper wire. The ease with which a demonstration homopolar motor can now be. Basic homopolar motor side view bottom view tiny dancer side view continue here start here continue here instructions.
Tom has done a good job in providing a text that is a recording of historical events and his own experiences homopolar research and development with a very detailed appendix. This device is easy to create and the figure below illustrates the basic concepts behind its operation. While their low torque and low efficiency make homopolar motors poor choices for common use, their simplicity, adaptability and easy of construction make them. A homopolar motor is a device that converts a magnetic field and a direct electrical current dc into motion. How to make a homopolar motor explained, the best science fair project ever for children, kids and easy.
Pdf during the application of simulation tools of computational. A homopolar motor is an electric motor in which the current flows in one direction, contrary to most motors whose current reverses, or is commutated, at least once every revolution. Whereas the homopolar motor converts electrical energy supplied by the cell into mechanical energy, the homopolar generator does the reverse. Homopolar indicates that the electrical polarity of the conductor and the magnetic field poles do not change, ie, the electricity is flowing in the same direction all the time. Homopolar motors we can use this to create something useful and fun. Tiny dancers a homopolar motor million women mentors. Build a simple electric motor homopolar motor frugal. However, they illustrate the principles nicely, and a homopolar motor is both easy to make and easy to understand.
Bend copper wire using template as a guide, continuing in 3d as indicated 3. The current flows downward in both wires, and the magnetic field is pointing approximately outward when it reaches the wires on the side. Research rail guns, with the potential to fire projectiles at twice the current speed of chemical based ballistics. Longitudinal section of dc homopolar motor applied to drive the ship.
Optical illusion game file format pdf size available in. Pdf a superconducting homopolar motor and generator. A homopolar motor uses direct current to power rotational movement, such as that generated by a battery. The main body of the device consists of a battery with two magnets on either end. A changing magnetic field generates an electric field, and this goes back to what is called electromagnetic induction. Homopolar motors hypothesis if we make the motor correctly, the copper wire will spin on top of the battery. This motor works because of electromagnetic force, called the lorentz force. Set copper wire up on battery, the wire just barely touching the magnet. This kit will help you in building one of the simplest electric motors, a homopolar motor also referred to as a monopolar motor. Consequently, by the right hand rule, the force points into the page on the left side and out of the page on the right side, causing the wire to rotate around the battery. The homopolar motor is also ran by electromagnetism.
The motor spins due to magnetic forces highlighted in the diagram to the right. A homopolar motor is a simple motor that uses a large current to generate mechanical movement. Some history to begin, this simple electric motor works on relationships between magnetism and electricity, first formulated by a frenchman in 1820, with the concept developed further in by a. A basic definition of the lorentz force is the force exerted by a magnetic field on a moving electrical charge. A homopolar one pole motor does not involve a polarity change as is utilized in more complex motors. The magnetic circuit consists of two halves made from armco iron. The resulting force being continuous in one direction, the homopolar motor needs no commutator but still requires slip rings. Direct current is applied to the disc and it rotates due to the effects of the current passing through the magnetic field. Build an elaborate homopolar motor, such as the tiny dancer see appendix what other uses are there for homopolar motors and the lorentz force. The cell provides current that flows through one brush to the central shaft, then outwards to the right towards the brush on the rim.
This simple concept can be used to create very simple motors using just a battery, a rare earth magnet or two and a wire. Pdf modelling and simulation of a simple homopolar motor. Some simple demonstration experiments involving homopolar motors. Pdf modelling and simulation of a simple homopolar motor of. Homopolar motor exploring the properties of electricity and magnetism materials a.
Build a standard homopolar motor using the rectangle piece of wire. A simple version of the homopolar motor almost guaranteed to work, comes from. Place wire on battery as indicated in template battery battery. Introduction to scripting in maxwell version 12, users manual. Clean energy science project for 5th grade this video that we saw on the kid should see this prompted me to buy the supplies to try this at home with my son. A simple homopolar motor, consisting of a battery, a neodymium strong magnet, some wire, and an iron screw.
The homopolar motor was the first electrical motor to be built. The homemade electric motor is made from household materials. Now lets try to build a homopolar motor that has the wire moving. Every day we use motors and batteries to power machines all around us, but what makes them go. How to make a homopolar motor best science fair project. A superconducting homopolar motor and generator new approaches article pdf available in superconductor science and technology 293.
Homopolar motor as presented by ligo science education center synopsis motors rely on moving electrical charges interacting with a magnetic field. This material is based upon work supported by the csub revitalizing science university program revsup funded by. Learn how to make both a basic homopolar motor and a tiny dancing motor. The homopolar motor is the first electrical motor to be built. Homopolar motor, homopolar generator university of new. Homopolarmotor aspresentedbyligoscienceeducationcenter. Ku 1 and ahmad kamal 1 synopsis a new homopolar motor has been designed and constructed based on the principle of the faraday disk. A homopolar motor is a direct current electric motor with two magnetic poles, the conductors of which always cut unidirectional lines of magnetic flux by rotating a conductor around a fixed axis so that the conductor is at right angles to a static magnetic field. Homopolar motor experiment by sahil devani on prezi. We shall use this example to study exact analytic solutions of the various homopolar generators that are discussed in the literature and online, which should provide the best insight. The rotor disk is made from a low carbon steel plate. Some simple demonstration experiments involving homopolar.
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