ELECTRICAL TRANSFORMERS

Ampere Turn The product of amperes times the number of turns in a coil. Autotransformer Any transformer in which primary and secondary connections are made to a single winding. The application of an auto transformer is a good choice where a 480Y /277V or 208Y/120 V, 3 phase, 4-wire distribution system is used Capacitance The storage of electricity in a capacitor or the opposition to voltage change. Capacitance is measured in farads or microfarads Flux The rate of energy flow across or through a surface. Also a substance used to promote or facilitate soldiering or welding by removing surface oxides. Induction The production of magnetization or electrification in a body by the mere proximity of magnetize or electrified bodies,or the production of an electric current in a conductor by the variation of the magnetic field in its vicinity. Magnetic induction The number of magnetic lines or the magnetic flux per unit of cross-sectional area perpendicular to the direction of the flux. Power transformer A transformer that is designed to transfere electrical power from the primary circuit to the secondary circuit to step up the secondary voltage at less current or step down the secondary voltage at more current, with the voltage-current product being constant for either the primary or secondary. Reactance The opposition to AC due to capacitance and / or the inductance Rectifiers Devices used to change alternating current to direct current. What is the primary function of a transformer in an electrical circuit? To transfer electrical energy between circuits, typically changing voltage and current levels. What is the role of the core in a transformer? To provide a path for magnetic flux, reducing energy losses and increasing efficiency. What happens to voltage in a step-up transformer? The voltage increases while the current decreases proportionally. How does a step-down transformer work? It reduces the voltage while increasing the current proportionally. What determines the turns ratio of a transformer? The ratio of the number of turns in the primary coil to the secondary coil. What is the purpose of insulation in a transformer? To prevent electrical short circuits and protect against leakage currents. What material is commonly used for transformer cores? Soft iron or silicon steel due to their magnetic properties and low energy loss. What causes transformer losses? Core losses (hysteresis and eddy currents) and copper losses (resistance in windings). Why is oil used in some transformers? For cooling and insulation purposes, helping to dissipate heat and maintain performance. What is meant by the efficiency of a transformer? The ratio of output power to input power, expressed as a percentage. How is magnetic flux linked between the primary and secondary windings? Through mutual induction facilitated by the transformer core. What is an autotransformer? A transformer with a single winding that acts as both the primary and secondary. Why is laminated core used in transformers? To reduce eddy current losses by increasing electrical resistance within the core. What does the term "load" mean in the context of a transformer? The electrical device or circuit connected to the secondary winding. What happens if a transformer is connected to DC instead of AC? It may overheat and get damaged because transformers rely on changing magnetic fields, which DC does not produce. What is the function of a tap changer in a transformer? To adjust the output voltage by changing the turns ratio. What is meant by leakage flux in a transformer? The magnetic flux that does not link both primary and secondary windings, reducing efficiency. What type of transformer is used for isolating circuits? An isolation transformer with a 1:1 turns ratio. What is the significance of the frequency in transformer operation? The core and winding design are frequency-dependent; operating outside the design frequency can cause inefficiency and overheating. The main purpose of a transformer is to change the output voltage the three parts of a basic transformer are the primary windings secondary windings and core when ac flows through a transformer coil, a ______ field is generated around the coils. magnetic when the field from one coil cuts through the turns of a second coil,______. voltage will be generated what causes voltage to be induced in a transformer? mutual induction in a transformer with a turns ratio of 5:1 ( the primary has five times the number of turns as the secondary ), what will be the voltage on the secondary if the primary voltage is 120v 24v the three basic types of iron core transformers are closed core open core and shell one effect caused by magnetic leakage in transformers is a lower secondary voltage if one of the transformers is damaged in a delta system, (n) ______ configurations may be used temporarily carry the load open delta the windings in an autotransformer are not isolated form one another true most controlled transformers are dry type step down a dry-type transformers must be housed in a vault if rated at more than 35kv the power factor of a circuit can be improved by increasing the capacitance a symptom of a transformer with an open circuit is no output on the secondary a(n) ______ should be used to measure insulation resistance megger A __________ is an electrical device that converts AC electricity from one voltage