Electric Motors

An electric motor converts electrical energy into mechanical energy. Most electric motors operate through the interaction between an electric motor's magnetic fields to generate force in the motor. Electric motors can be utilized in numerous applications such as machine tools, industrial fans, pumps, watches, generators, household appliances, power tools as well as many others.
There are many different types of electric motors, this is a graph that shows the different kinds:

Major Categories

by

Type of Motor Commutation

Self-Commutated			Externally Commutated
Mechanical- Commutator Motors		Electronic- Commutator (EC) Motors	Asynchronous Machines	Synchronous Machines
AC	DC	AC	AC
* Universal motor (AC commutator series motoror AC/DC motor) * Repulsion motor	Electrically excited DC motor: * Separately excited * Series * Shunt * Compound PM DC motor	With PM rotor: * BLDC motor With ferromagnetic rotor: * SRM	Three-phase motors: * SCIM * WRIM AC motors: * Capacitor * Resistance * Split * Shaded-pole	Three-phase motors: * WRSM * PMSM or BLAC motor - IPMSM - SPMSM * Hybrid AC motors: * Permanent-split capacitor * Hysteresis * Stepper * SyRM * SyRM-PM hybrid
Simple electronics	Rectifier, linear transistor(s) or DC chopper	More elaborate electronics	Most elaborate electronics (VFD), when provided

 There are also many different components that are required in order to construct and electric motor:

Rotor: In an electric motor the moving part is the rotor which turns the shaft to deliver the mechanical power. The rotor usually has conductors laid into it which carry currents that interact with the magnetic field of the stator to generate the forces that turn the shaft. This is an example of a rotor and.

Stator:The stationary part is the stator, usually has either windings or permanent magnets. The stator is the stationary part of the motor’s electromagnetic circuit. The stator core is made up of many thin metal sheets, called laminations. Laminations are used to reduce energy loses that would result if a solid core were used.
Windings: Windings are wires that are laid in coils, usually wrapped around a laminated soft iron magnetic core so as to form magnetic poles when energized with current.
Commutator: A commutator is a mechanism used to switch the input of certain AC and DC machines consisting of slip ring segments insulated from each other and from the electric motor's shaft. The motor's armature current is supplied through the stationary brushes in contact with the revolving commutator, which causes required current reversal and applies power to the machine in an optimal manner as the rotor rotates from pole to pole. This diagram shows how a commutator operates:

Source: http://www.seaperch.org/electric_motors

My Motor 2

For the most part, I followed the plan that I laid out for myself in the beginning of the project. One problem I experienced while making the motor was that I could not get my electromagnet to work properly. This was most likely because I overlapped the magnet wire when I wrapped it around the metal. In order to fix this problem I was forced to recreate the electromagnet again. Another problem I was faced with when making the motor was that I could not properly create a proper connection between the commutator and the armature. I am unsure as to why this connection was not formed correctly the first attempt but after re-taping the magnet wire from the armature to the copper plates several times I was able to form a proper connection. The brushes also gave me difficulty because the way I had them situated caused the turning commutator to stop turning. After shaping my L brackets a little differently so that the brushes could come in contact with the commutator while being perfectly vertical, I was able form a successful connection. Although the actual construction of this project did not take an extraordinary amount of time, the tweaking and adjusting of many components took a great deal of time because I was often unsure as to what was wrong with certain connections. However after all of that time, it was a truly amazing feeling to see that I had the capability to make something that worked properly.

My Motor 1

In the beginning stages of the motor project, I planned out how I would construct my motor. My original design would be constructed with 24 gauge magnet wire for the armature and electromagnet base instead of using lamp wire for the electro magnet. I did this because I felt that it would be easier and simpler to construct the electromagnet base with magnet wire than single strand lamp wire. In addition, I planned to create the brushes by attaching lamp wire to the outside of a L shaped steel bracket on each side of the armature. One of these L brackets would be connected to the electromagnet base and the other one would be connected by pliers to the battery. The brushes I made would then connect to two copper rectangles that would be shaped around a cork placed on the rod carrying the armature to form the commutator. Also, the two copper rectangles would be connected to the armature in order to transfer the electrical current to it. Lastly, the second plier connected to the battery would be connected to the electromagnet to complete the circuit. My motor was planned to be built to somewhat resemble this model:

Static Equilibrium

Static Equilibrium is the physical state in which all components of a system are at rest and the net force is equal to zero throughout the system. When a system is in static equilibrium, it means that all the components of the system are not accelerating as a result of the net force equaling zero. An example of a system in static equilibrium is a game of tug of war.

This system of forces is considered to be in static equilibrium because the force that is being applied by the first man is equal to the opposite force being applied by the second man. Therefore, the sum of the forces, or the net force of the system, equals zero. Since the forces are balanced, it also means that there will not be any acceleration of the rope in either direction.

In addition, another characteristic of a system of forces that is in static equilibrium is that the system also has zero torque. Torque is a measure of the turning force on an object. Torque can be thought of as a twist to an object. An example of a system of forces that seems like it should be in static equilibrium is this diagram because te forces are balanced. However, there is torque in the system, which will cause the system to rotate.

My Bridge

When constructing my bridge I plan to produce a relatively basic truss bridge. By studying other successful balsa wood bridges on balsabridge.com I have found that the best bridges utilize either a truss or a piece of circular bent wood acting as a different type of truss. I decided to go with a truss because I believe that it is a slightly more basic structure type to understand and that it will be easier to construct. I took how easy the bridge was to construct into consideration because I wanted to try to decrease the percentage of error of my bridge failing as much as I possibly could. The design of my bridge looks much like this design:

I feel like this design was one of the best designs for constructing a balsa wood bridge because this is a strong truss design which will distribute the force that is applied by the weight nicely. In addition, this truss design is one that does not have an upright beam that is located at the midpoint of the bridge. This makes this design one that can be used for this particular project because if it were to have that upright beam at the midpoint then the metal rod that suspends the weight would not be able to be placed there.

Bridges

A bridge is a structure built to span physical obstacles for the purpose of providing passage over the obstacle. Bridges may be classified by how the forces of tension, compression, bending, torsion and shear are distributed through their structure. Here are a few of the many structure types.


Beam Bridge: Beam bridges are the most basic of bridge structures. They are made up of horizontal beams that are supported at each end. The earliest of beam bridges were most likely logs laid out across rivers or other gaps.

Arch Bridge: An arch bridge is a bridge with abutments, or structures built to support lateral pressure on each end shaped as arches. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. The earliest known arch bridges were built by the Ancient Greeks.

Truss Bridge: A truss bridge is a bridge that utilizes a truss in its a structure. This truss is a structure of connected elements forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or sometimes both in response to dynamic loads. The truss bridge is one of the oldest structure types that are still commonly used today.

Suspension Bridge: Suspension bridges are suspended from cables. These cables are hung from towers that go very deep down into the ground. The earliest suspension bridges were made of ropes or vines covered with pieces of bamboo.