Transformers Basic Concepts of Transformers Transformer: An electrical device that transfers electrical energy between two circuits using electromagnetic induction. Transformers are primarily used to step up or step down voltage levels. — Key Vocabulary Primary Winding (Np ): The coil connected to the input voltage source. Secondary Winding (Ns ): The coil connected to the output load. Turns Ratio (n): The ratio of the number of turns in the secondary winding to the number of turns in the primary winding: n= Ns Np Voltage Ratio: The ratio of the secondary voltage (Vs ) to the primary voltage (Vp ): Vs =n Vp Current Ratio: The ratio of the primary current (Ip ) to the secondary current (Is ): Ip =n Is Step-Up Transformer: A transformer where n > 1, meaning the secondary voltage is higher than the primary voltage. Step-Down Transformer: A transformer where n < 1, meaning the secondary voltage is lower than the primary voltage. 1 Magnetic Flux (Φ): The measure of the total magnetic field passing through a given area, crucial for inducing voltage in transformer windings. — Transformer Equations 1. Voltage Transformation: Ns Vs = Vp Np 2. Current Transformation: Ip Ns = Is Np 3. Power Relationship: In an ideal transformer (no energy loss): P p = Ps or Vp · Ip = Vs · Is 4. Impedance Transformation: The impedance seen by the primary is proportional to the square of the turns ratio: Zs = n2 Zp — Types of Transformers Step-Up Transformer: - Increases voltage. - Decreases current. - Commonly used in power transmission. Step-Down Transformer: - Decreases voltage. - Increases current. - Used in power distribution to homes. Isolation Transformer: - Has a 1:1 turns ratio (n = 1). - Used to isolate electrical circuits for safety. Three-Phase Transformer: - Used in power systems for transmitting large amounts of energy efficiently. - Configurations include Delta (∆) and Wye (Y ) connections. — 2 Transformer Losses Copper Losses: Heat losses due to the resistance of the windings (I 2 R). Core Losses: Losses in the magnetic core, including: • Hysteresis Loss: Energy loss due to the repeated magnetization and demagnetization of the core. • Eddy Current Loss: Circulating currents within the core material that cause heat. Leakage Flux: Magnetic flux that does not fully link the primary and secondary windings. Efficiency: The ratio of output power to input power: η= Ps × 100% Pp — Applications of Transformers • Power Transmission: Step-up transformers are used to reduce current and minimize losses during long-distance transmission. • Power Distribution: Step-down transformers reduce voltage for safe residential and industrial use. • Impedance Matching: Ensures maximum power transfer in audio systems and communication circuits. • Electrical Isolation: Isolates sensitive circuits to prevent electrical noise and ensure safety. — Conclusion Transformers are vital components in electrical systems, enabling efficient power transmission, distribution, and various specialized applications. Understanding their key concepts and vocabulary is essential for analyzing and designing transformer-based systems. — 3