Transcript GENERATORS AND TRANSFORMERS
TRANSFORMERS Induced Current Review • The effect of inducing a current in a coil by moving a magnet inside it is used for the generation of electricity in power plants • There are two types of generator or dynamo. Both turn rotational energy into electrical energy. 1. One type involves rotating a coil inside a magnet. 2. The other type involves rotating a magnet inside a coil Both types produce ALTERNATING CURRENT. Why do we need transformers? • In most cases, machines and appliances using electricity are manufactured to operate using a specific voltage and frequency. However, not all countries- and sometimes not all regions within the same country- generate the same voltage and frequency in their electricity. TRANSFORMERS • This is where transformers com in. Transformers adjust the voltage coming into the appliance to the proper level, and move it through the appliance to keep it running properly. TRANSFORMER • A transformer can change electrical energy of a given voltage into electrical energy at a different voltage level. It consists of two coils arranged in such a way that the magnetic field surrounding one coil cuts through the other coil. • Transformers can step up the voltage or step it down. – We step up voltage to send it over long distances – We step down voltage in order to use in houses This transformer's job is to reduce the 4160 volts down to the 240 volts that makes up normal household electrical service. It is a step down transformer http://science.howstuffworks.com/power3.htm Step Up Transformer at Power Plant TRANSFORMER • The factor which determines whether a transformer is a step up( increasing the voltage) or step down (decreasing the voltage) type is the "turns" ratio. The turns ratio is the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. Step-up Transformer http://www.ibiblio.org/kuphaldt/electricCircuits/AC/AC_9.html • https://www.youtube.com/watch?v=Zjwzpo CiF8A • https://www.youtube.com/watch?v=Vucso EhB0NA EXIT TICKET • On a piece of paper answer the following questions: – What is the difference between AC and DC? – How do we generate electricity? – Why do we need transformers?