Anglicky v odborných předmětech "Support of teaching technical subjects in English “

1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Physics Topic: Alternator Prepared by: RNDr. Ondřej Jeřábek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. Alternator

3. Alternator General information: • Alternator is rotary electric machine • Changes rotary energy ( kinetics energy ) or mechanical energy to electric energy • Output capacity is led to electrical system

4. Alternatorfunction • Alternator works on electrical induction principle • Voltage is induced in conductor, if conductor and magnetic field move to each other • Extent of induced voltage depends on magnetic field rate and conductor movement speed ( engine revolutions )

5. Construction • Alternators are synchronous machines • According to their rotor’s type they further divide to: • With plain rotor- turbo-alternators – driving machine is mostly steam turbine (in steam power plant) speed turns 3000 min-1, as network freqeuency 50 Hz • Low-acting alternators are driven by low-acting machine (mostly by water turbine). Speed turn is whole number ratio of 3000 min-1, as network frequency 50 Hz • It makes mechanically connected set with driving machine. Driving machine and alternator are on the same shaft.

6. Alternatoradvantages • Alternator with rectifier is designed so that accumulator is charged when combustion engine runs idle • It is important advantage for city traffic • Accumulator durability charged by alternator with rectifier is longer than accumulator durability charged by dynamo • Alternator is excited directly of accumulator immediately after ignition start

7. Alternatorfunction • Alternators produce electricity in the same way as direct-current generators • Rotating magnet rotates – rotor inside stationary fit windings on iron cores - stator • Electrical current is produced by rotor movement caused by mechanic energy • There are mostly sets of stator windings in stator that are moved round slight amount of 180° • Rotor magnetic field can be caused by induction or permanent magnet

8. Alternatorusage in cars • Car alternator has the same construction as industrial alternators • Car alternator produces 3- phase • electrical current • Alternating current must be rectified before entry to car network • Diodes are used to rectifying of alternating current • Diodes are fixed to diode bridge • To limitation of voltage values , alternator output direct current is controlled by Zener diode • Alternator advantage comparing with dynamo is mainly its low weight

9. Activity I • Find out alternator on the Internet: • Alternator´s rotor and stator • Find out on the Internet alternator wiring diagram wired to electrical circuit

10. Activity II • Describe main alternator components that you found out on the Internet • Describe and explain alternator wiring to electrical circuit

11. Literature • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 1. Brno : Avid, 2004. 211 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 2. Brno : Avid, 2004. 120 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 3. Brno : Avid, 2004. 220 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 4. Brno : Avid, 2004. 350 s. Translation: • www.seznam.cz • www.slovnik.cz • JANATA, Petr. Handy slovník technický anglicko-český a česko-anglický. Plzeň: Nakladatelství Fraus, 2000. ISBN 80-7238-075-3 • Lingea LEXIKON 5, Technický slovník anglicko-český a česko-anglický. 2010.