1 / 15

Transformers

Transformers. Transformers. Chesapeak e College ETT-110. Transformer. A device which changes alternating current to different voltage and current levels. STEP UP Transformers increase STEP DOWN Transformers decrease

necia
Télécharger la présentation

Transformers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Transformers Transformers Chesapeake College ETT-110

  2. Transformer A device which changes alternating current to different voltage and current levels. • STEP UP Transformers increase • STEP DOWN Transformers decrease • ISOLATION transformers will keep the voltage equal and its main function is to separate one part of a circuit from another as a means of protection.

  3. Magnetic Field Around a Coiled Wire There exists a strong connection between Magnetic fields andElectrical current flow. As current flows through the a coiled conductor, a strong Magnetic field is expanding around the conductor. The greater the number of windings and current flow, the stronger the Magnetic Field. Michael Faraday

  4. Remember the Inductor? • As current flows through the coils of an inductor, a strong magnetic field begins to expand around the conductor. • Energy is stored inside this magnetic field.

  5. Transformer Transfers electrical energy from one circuit to another by Mutual Inductance Transformers are made of two sets of fixed coils wrapped around a common iron core. The INPUT coil is called the Primary and the OUTPUT coil is called the Secondary.

  6. Magnetic Field Around the Primary There exists a strong connection between Magnetic fields and Electrical current flow. As current flows through the Primary Coil of the transformer, a strong magnetic field is expanding around the conductor. The greater the windings and current flow, the stronger the Magnetic Field. Michael Faraday

  7. Mutual Induction in the Secondary Electrons are negatively charged particles. When the magnetic field generated by conduction in transformer’s primary coil, cuts through the secondary coil, it causes the electrons to be propelled in one direction or the other. Current flow is caused by the magnetic field displacing the electrons within the conductor, hence current is said to be induced. Current in the secondary coil flows in the opposite direction of current flow in the primary coil. Michael Faraday

  8. Transformer Action • As an AC Voltage is applied to the Primary (input) Coil, the resulting current flow generates a magnetic field that is constantly expanding and collapsing.

  9. Transformer Action • There is no physical contact between the the primary and secondary windings. In fact they are both insulated from each other. • There is no known insulation from the influence of magnetic fields.

  10. Transformer Action • Energy is transferred from the primary winding to the secondary winding by the MOVEMENT of the magnetic fields.

  11. Strength of Transferred Energy • The value of the voltage induced into the secondary winding depends upon • The strength of the input voltage on the primary • The RATIO of number of secondary turns to the number of turns in the primary coil. The Frequency does not change across the transformer. Therefore the output frequency will equal the input frequency.

  12. TURNS RATIO • The Ratio of the number of turns in the primary coil to the number of turns in the secondary coil. • The Voltage Ratio is equal the to Turns Ratio

  13. Example of Turns Ratio A transformer is wound with 8 turns on the primary coil and 4 turns on the secondary coil. If 8 volts AC is applied to the primary, how much is induced into the secondary? Theoretically, the voltage induced into each individual turn of the primary equals the total voltage applied. Therefore we take 8 VAC and divide it by 8 turns of the primary and we get a value of 1 VAC in each turn. If that 1VAC is induced into each turn of the secondary, we take 1 VAC and multiply it by 4 turns. Therefore the resulting voltage out of the transformer is 4 VAC.

  14. STEP UP TRANSFORMERS • A transformer where the secondary coil output voltage is greater than the primary coil output voltage. • There are more turns in the secondary coil than in the primary Coil.

  15. STEP DOWN TRANSFORMERS • A transformer where the secondary coil output voltage is lessthan the primary coil output voltage. • There are less turnsin the secondary coil than in the primary coil.

More Related