Step-up and Step-down transformers are used to increase and decrease voltage respectively. Mains electrics what we use in our homes runs at V, so a step down tranformer is needed to reduce the voltage to this safe level.
Why are transformers used in the National Grid? Answered by Mike R. In the UK, about 8. Most transformers in the system were installed during the s when demand for electricity increased rapidly. The efficiency of many of these 40 year-old transformers is poor compared to the best practice of today. The losses in the coils are known as load losses. They increase with the square of the current being taken from the transformer.
Load losses are minimised by using copper windings for low resistance. Imagine you want to supply electricity to a remote house, which has a peak requirement of The 3 km cable to the house has a resistance of 50W. It is suggested that the transmission cables use the same voltage as the house — V. Work through the parts to see if this is sensible use the peak power for all the parts. We will need a step-down transformer at the house to get the voltage back to V.
Go to the download section to access zip files of all resources for each subject and age group for use offline. Transformers Using transformers We use transformers to change the size of a voltage. Copper windings in a transformer. Courtesy of physbot. The table below shows the calculations. It is therefore desirable to manufacture and install more efficient transformers.
Losses occur: in the primary coil and secondary coil because of their electrical resistance in the core because energy is lost as the magnetic field changes, and because small currents are induced in the core, and these waste energy. The core losses are minimised by using high quality steel for the core. Questions 1. Which of the following are true statements about a step-up transformer? Imagine that we increase the supply voltage by a factor of Return to Copper and Electricity: Generation.
Discover the Answers. Before reaching the end user, a step-down transformer , reduces the voltage from the transmission voltage to the safer voltage of V for home use. As an electric current flows through the thick cables held up by the pylons, they will get hotter and dissipate energy to the surroundings.
The electrical power dissipated depends on current and resistance:. This is when:. To reduce these losses, the National Grid transmits electricity at a low current. This needs a high voltage. Power stations produce electricity at 25, V.
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