In US residences electrical power is generally utilized at a

In U.S. residences. electrical power is generally utilized at a nominal voltage of 120 Wins. What key problem can you identify if the residential power distribution system and household appliances had been designed for a lower voltage like 12 Vrms? What key problem can you identify if the residential power distribution system and household appliances had been designed for a higher voltage like 12 kVrms?

Solution

Household appliances can basically be categorised into two categories:

1. appliances without motors (resistive loads)

2. appliances with motors (inductive loads)

a) For appliances without motors, when the supply voltage is higher than the device rated voltage, more current will flow through the devices and will result in burning of the devices. If they do not burn, they will consume more electricity.

For appliances with motors, they will draw more current only at the time of starting, but once they reach the steady state, they will draw normal current. But still, the high starting current may damage the devices as this starting current will be much much higher than they are designed to handle the starting current at rated voltage.

b) For appliances without motors, less current will flow through them and their output will be small- bulbs will be dim, heaters will heat less, etc.

For appliances with motors, either they will not start at all or they will run at much lower capacity with a humming sound.