Generatorsand

Motors

By: Group VI

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GeneratorMotor

Their DifferenceTrivias and other Facts

Group VI members

What is it? History ApplicationsParts

What is it? History ApplicationsParts

A generator is a device that uses the principle of

electromagnetic induction to produce electricity.

It is a device that converts mechanical

energy to electrical energy.

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The electric generator was first made in 1790 by a man named Luigi Aloisio Galvani.

Over the years, scientists improved the practical and theoretical parts of the equipment. In 1831,

another man (named Michael Faraday), discovered the operating principal of

electromagnetic generators. The principle is now called Faraday's Law.

The first workable units though for generating power were created by Nikola Tesla. He is

created with the creation of alternating current, which requires a method of creation. He is also credited with the creation of the motor which is

very similar in construction to the generator.

History

Applications in General :•The DC generator system is designed and optimized to deliver the high currents at low voltages required for battery charging and operating DC loads. No battery chargers or power supplies are required.•DC generators do not require a transfer switch. Transfer switches lower system reliability.•In prime power applications the DC generator lowers the overall cost of the system.•Certain AC generators and switch mode power supplies are incompatible. These AC generators have voltage regulators that cannot regulate voltage due to the current pulsing load of the switch mode power supplies. Polar's DC generators when connected to a battery do not suffer this incompatibility.•DC generators are more fuel-efficient. Site operators want the longest run time with the least amount of fuel on site.•Polar's DC generators are simpler in design, have considerably less maintenance and are more reliable than AC generators. Propane carburetion and electronic speed governors require frequent calibration and testing. If the propane carburetion, ignition system, or governor speed control should develop a problem, alternator voltage regulation and frequency control will fail. Some equipment powered by the generator will be damaged, other equipment may survive. How many of your AC loads can tolerate a wide swing in frequency?•Maintainability. DC generators use smaller engines that can be lifted by hand and transported to a shop for repair. The high-level generator mechanics are not required, or their expensive travel time to the site.•DC generator lowers the costs to install and operate. It is smaller in size and requires less site support. Transport to the site and installation is facilitated because: smaller shelter and concrete pads can be used, elevator transport to roof rather than crane, smaller helicopters or vehicles for transport. Fuel consumption is lower, so cost to transport fuel to the site is lower (transportation of the fuel to the site can be very expensive).

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Applications

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A generator has two basic parts.

MagnetsWire loop

Magnets

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Magnets are pieces of metal that have the ability to attract other metals. Every magnet has two poles: a north and a south. Much

like electrical charges, two similar magnetic poles repel each other; while opposite magnetic poles attract each other.

Magnets have a continuous force around them that is known as a magnetic field. This field enables them to attract other metals. Figure 1 illustrates this force using bar and horseshoe magnets.

Accordingly, Faraday's law states that induced voltage can be determined by the number of turns in a coil, and how fast the coil cuts through a magnetic

field. Therefore, the more turns in a coil or the stronger the magnetic field, the more voltage induced.

In addition, current changes direction depending on which way it cuts across a magnetic field. As depicted

in Figure 5, a coil cutting through a basic magnetic field in a clockwise direction will at first result in a

current with positive polarity, but as it cuts across the same field in the opposite direction during the second

half of its turn, the polarity becomes negative.

Generator Parts

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Generator Parts

Wire Loop

When a wire is moved in a magnetic field, then the current is induced in the coil. A rectangular coil is made to rotate rapidly in the magnetic field between the poles of a horse shoe type magnet. When the coil rotates, it cuts the lines of magnetic force, due to which a current is produced in the generator coil. This current can be used to run the various electrical appliances.

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The electric motor is at the heart of many devices,

electrical and electronic. It turns electrical energy into

mechanical energy. An electric motor is all about

magnets and magnetism: A motor uses magnets to

create motion.

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History

In 1827, Hungarian physicist Ányos Jedlik started experimenting with devices

he called "electromagnetic self-rotors". Although they were used only for

instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three main components of practical

direct current motors: the stator, rotor and commutator. The

device employed no permanent magnets, as the magnetic fields of both the

stationary and revolving components were produced solely by the currents

flowing through their windings.

In 1855 Jedlik built a device using similar principles to those used in

his electromagnetic self-rotors that was capable of useful work. He built

a model electric motor-propelled vehicle that same year.

The first commutator-type direct current electric motor capable of

turning machinery was invented by the British scientist William

Sturgeon in 1832.

The modern DC motor was invented by accident in 1873, when Zénobe

Gramme connected the dynamo he had invented to a second similar

unit, driving it as a motor. The Gramme machine was the first electric motor that was successful

in the industry.

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Parts

Field Magnet and Power supply

Armature

Axle

Commutator And

Brush

Field Magnet and Power Supply

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MotorParts

To understand how an electric motor works, the key is to understand how the electromagnet works.

An electromagnet is the basis of an electric motor. The conductor would become a magnet and have a north

and south pole while it is connected to the power supply. The north end of the electromagnet would be repelled from the north end of the horseshoe magnet

and attracted to the south end of the horseshoe magnet. The south end of the electromagnet would

be repelled in a similar way. The flip causes the electromagnet to complete another half-turn of

motion. You flip the magnetic field just by changing the direction of the electrons flowing in the wire. If

the field of the electromagnet were flipped at precisely the right moment at the end of each half-

turn of motion, the electric motor would spin freely.

Armature

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MotorParts

Consider the image on the previous page. The armature takes the place of the nail in an

electric motor. The armature is an electromagnet made by coiling thin wire around two or more

poles of a metal core.The armature has an axle, and the commutator is attached to the AXLE. In the diagram to the right,

you can see three different views of the same armature: front, side and end-on. In the end-on

view, the winding is eliminated to make the commutator more obvious. You can see that the commutator is simply a pair of plates attached to

the axle. These plates provide the two connections for the coil of the electromagnet.

Commutator and Brushes

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MotorParts

The "flipping the electric field" part of an electric motor is accomplished by two parts:

the commutator and the brushes.The diagram at the right shows how the

commutator and brushes work together to let current flow to the electromagnet, and also to flip the direction that the electrons are flowing at just the right moment. The

contacts of the commutator are attached to the axle of the electromagnet, so they spin with the magnet. The brushes are just two

pieces of springy metal or carbon that make contact with the contacts of the commutator.

Axle

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MotorParts

It allows the conductor to move while it is flipping

because of repulsion and attraction of magnetic fields.

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Electric motors are used in many, if not most, modern machines. Obvious uses would be in rotating machines such as fans, turbines, drills, the wheels on electric cars, locomotives and conveyor belts. Also, in many vibrating or oscillating machines, an electric motor spins an irregular figure with more area on one side of the axle than the other, causing it to appear to be moving up and down.Electric motors are also popular in robotics. They are used to turn the wheels of vehicular robots, and servo motors are used to turn arms and legs in humanoid robots. In flying robots, along with helicopters, a motor causes a propeller or wide, flat blades to spin and create lift force, allowing vertical motion.Electric motors are replacing hydraulic cylinders in airplanes and military equipment.In industrial and manufacturing businesses, electric motors are used to turn saws and blades in cutting and slicing processes, and to spin gears and mixers (the latter very common in food manufacturing). Linear motors are often used to push products into containers horizontally.Many kitchen appliances also use electric motors to accomplish various jobs. Food processors and grinders spin blades to chop and break up foods. Blenders use electric motors to mix liquids, and microwave ovens use motors to turn the tray food sits on. Toaster ovens also use electric motors to turn a conveyor to move food over heating elements.

Applications

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The Difference Between

Generator and Motor Generator Motor

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Uses the principle of electromagnetic induction to produce electricity.Doesn’t have batteries

or any power supply.

A loop without current is manually rotated in the presence of a magnetic field to produce current in the loop.

Transforms mechanical energy to electric energy.

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Needs power supply to function.

Current flown through coil in presence of magnetic field, resulting in motion.

It doesn’t need aturbine or any other prime mover.

Transforms electrical energy to mechanical energy.

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DID YOU KNOW THAT?

A generator is basically a motor that is operated in

reverse.

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The Group VINathaniel EgunaJoseph Dacullo

Vince Angelo DeymosJonel Daigdigan

Mark Lester Flores

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