Answer to Question #190781 in Electric Circuits for jessica martini

Question

Rob has moved from North America to Australia, bringing most of his household effects including a portable room heater built for use in North America. The heater’s label says it is rated for 1500 W. He has planned to purchase a voltage conversion transformer so that he can operate these devices in his Australian home.

A. Explain how a transformer operates in general and how a transformer can be designed to convert input voltage to a different output voltage. (5 marks)

B. A friend proposes an inexpensive alternative to using a transformer. He says to go to purchase a standard Australian 2 prong plug from a hardware store, cut off the original plug from the heater’s cord and then connect the Australian plug to the wires of the cord. Explain why this approach is likely both a fire hazard and a shock hazard. (5 marks)

Answer 1

The power need to the electrical household = 1500W

a) But we know that the supplied voltage to the household is not that much capable to operate this device. Hence he need to use the transformer.

We know that $P=VI$

Voltage signal can be amplify to increase the number of turns in the coil of transformer.

$\frac{N_P}{N_S}=\frac{V_P}{V_S}$

Hence, the power can be reach to the required transformer signal.

b) He proposed because he know that electric heat has a long coiled wire and the number of turns is very large so the power can be amplify but we should care about the resistance of the heater wire, it has very high resistance and when the electric current will get supplied in the coiled wire then it will get burned and due to large heating emission, the connected wire will get melt.