Chapter 24: Induction and Transformers Flashcards
What is the structure of a transformer?
A current carrying wire is wrapped around one side of a transformer, and another wire is wrapped around the other. The transformer is made of iron, and each wire has a different number of coils.
How does the transformer change the size of an alternating voltage?
By having different numbers of turns on the input and output sides. More could cause higher voltage, so if on the output there are more, it is a step up transformer, and if there are more on the input, it is a step down.
When is a voltage induced in a conductor?
A voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it. The movement is relative - only requirement is to cut flux lines.
What factors affect the size of the induced voltage in the secondary coil?
Strength of magnetic field, number of coils and speed of rotation
What is the relationship between number of turns and voltage in a transformer?
Np/Ns = Vp/Vs
What happens to power in the transformer?
Input power = output power
What is the relationship between voltage and current in the transformer?
Vp x Ip = Vs x Is
How does the generation of electricity work with movement, electricity and a magnetic field?
Rotate a magnet in a coil of wire, and current will be induced. The motion is relative, so it can happen in the opposite way.
What factors affect the size of induced voltage?
Magnetic field strength, speed of movement, number of coils of wire
How are step-up and step-down transformers used in large-scale generation and transmission of electrical energy?
Transformers are used in the national grid. When electricity leaves a power plant, a step-up transformer is used to increase the voltage and decrease the current, reducing energy loss and making transmission safer. When electricity reaches a home or business, a step-down transformer is used to make it useful in the appliances we use and as the wires are short, less danger is presented.
