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Generators

Generators. Inducing current in a wire. Fleming’s right-hand rule. It is possible to predict the direction of the induced current produced by a generator if the direction of the force (or motion) or the magnetic field are known. Fleming’s right-hand rule is used to do this. thu M b = M otion.

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Generators

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  1. Generators

  2. Inducing current in a wire

  3. Fleming’s right-hand rule It is possible to predict the direction of the induced current produced by a generator if the direction of the force(or motion) or the magnetic field are known.Fleming’s right-hand rule is used to do this. thuMb = Motion First finger = magnetic Field seCond finger = Current

  4. What is electromagnetic induction? When current flows through a wire held in a magnetic field, a force is created that moves the wire. This is the motor effect. The opposite is also possible: if a wire is moved across a magnetic field, a current is produced. This is electromagnetic induction. Induction also occurs if a magnet is moved in a coil of wire, or if a coil of wire rotates in a magnetic field. In all these methods of inducing a current, the wire and magnetic field move perpendicular to each other. If they move parallel to each other, no current is induced.

  5. Inducing current in a coil

  6. Magnet and coil: relative movement Electromagnetic induction depends on relative movement between the magnet and the coil. It doesn’t matter whether it is the coil (top) or the magnet (bottom) that is moving. If there is no movement, then there will be no electromagnetic induction and no voltage produced across the ends of the coil. Primary energy sourcesare used to produce this movement in wind turbines or coal-fired power stations.

  7. Varying the size of the induced current

  8. Factors affecting induced current

  9. What are generators? A generator is a device that converts kinetic energy into electrical energy. It is the opposite of an electric motor. Power stations use generators to produce electricity on a large scale. Kinetic energy is provided by rotating turbines that can be powered by: • high-pressure steam – in coal, oil, gas and nuclear power stations • wind – in wind turbines • falling water – in hydroelectric power stations.

  10. How do AC generators work?

  11. AC generator simulation

  12. Increasing the size of the induced current How can the size of an induced current be increased? • increase the speed at which the coil rotates • increase the strength of the magnetic field • increase the number of turns in the coil • increase the total area of the coil. An electromagnet is often used in a power station generator. This can provide a stronger magnetic field than a permanent magnet.

  13. Why produce AC? Some generators can produce direct current (DC) and many small household appliances use DC. What advantage does AC have over DC? The main reason is because it is easy to change AC voltages. Voltages are increased (to around 300000V) to reduce energy loss during transmission. Voltage is decreased to 230V before it reaches homes, and reduced again in many appliances (such as phone chargers).

  14. Glossary

  15. Generators: true or false?

  16. Multiple-choice quiz

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