AC-AC Transformers Flashcards
(40 cards)
What do AC-AC transformers do?
AC-AC transformers transfer electrical energy between circuits, changing voltage and current levels while isolating circuits.
How do transformers work?
They operate on the principle of electromagnetic induction, transferring energy between primary and secondary windings through a magnetic core.
What are the main types of transformers?
Step-up, step-down, isolation, autotransformers, and current transformers.
What is a step-up transformer?
A transformer that increases voltage from the primary to the secondary winding.
What is a step-down transformer?
A transformer that decreases voltage from the primary to the secondary winding.
What is an isolation transformer?
A transformer with a 1:1 turns ratio used to electrically isolate two circuits.
What is an autotransformer?
A transformer with a single winding that acts as both primary and secondary, sharing part of the winding.
What is a current transformer (CT)?
A transformer used to measure current in high-power circuits by producing a proportional lower current.
What is the turns ratio in a transformer?
The ratio of the number of turns in the primary winding to the number of turns in the secondary winding.
How do you calculate the voltage ratio of a transformer?
Vsecondary/Vprimary = Nsecondary/Nprimary
Where N is the number of turns.
What is the efficiency of a transformer?
The ratio of output power to input power, typically expressed as a percentage.
What is the purpose of the core in a transformer?
To provide a path for the magnetic flux, improving efficiency and reducing losses.
What materials are used for transformer cores?
Laminated iron, ferrite, or powered iron, depending on the frequency and power requirements.
What is the role of insulation in a transformer?
To prevent electrical short circuits between windings and the core.
What is a laminated core transformer?
A transformer with a core made of thin, insulated layers of iron to reduce eddy current losses.
What are eddy currents in transformers?
Circulating currents induced in the core, causing power loss and heat generation.
What is a toroidal transformer?
A transformer with a doughnut-shaped core, offering higher efficiency and lower electromagnetic interference.
What is the impedance of a transformer?
The opposition to alternating current, determined by the winding resistance and leakage reactance.
What is a center-tapped transformer?
A transformer with a secondary winding that has a connection in the middle, providing two equal voltages.
What is a multitap transformer?
A transformer with multiple taps on the winding to provide different voltage outputs.
What is the purpose of a multitap transformer?
To provide multiple voltage levels for different circuit requirements.
What is a three-phase transformer?
A transformer designed to work with three-phase power systems, often used in industrial applications.
How are transformers cooled?
Through air, oil, or forced cooling systems to dissipate heat generated during operation.
What is a transformer regulation?
The change in output voltage from no load to full load, expressed as a percentage.