Why are gas dryers run on 120V and electric dryers run on 220V?

Answer 1

The main reason we supply 220 volts to a clothes dryer and 110 volts to a toaster is that the dryer needs a lot more powerthan the toaster. To transfer power, we have a voltage and then deliver enough amps to supply the power. Volts times amps is power (watts). Let's look at that a bit. When we supply power, we supply a combination of volts and amps. As an example, if we supply 10 amps at 10 volts, we supply 100 watts. But we could supply 100 watts by using 5 amps at 20 volts. Or 25 amps at 4 volts. As you can see, various combinations of voltages and currents will deliver the same power. In the case of the dryer, we elect to use a higher voltage so we don't have to supply so much current. Though high voltages can be dangerous, the demands associated with supplying large currents present problems, too. The 220 volts is available across the pair of 110-volt electrical buses of the mains, so the idea of using the 220 was chosen to avoid higher currents and the need to use much heavier (larger gauge) wiring in the electrical drop or utility line. Also, because we'd be shoving so much more current through the circuits at lower voltage, we'd encounter higher resistive losses. A higher voltage and a lower current (to deliver the same power) makes for less loss and more efficiency.

Answer 2

The reason is to give the dryer more heating power for a given size of wiring at a safe current taken from the main supply panel.

Electrical power is calculated by multiplying the voltage by the current drawn.

So if a dryer runs on 240V (V) and draws 30 Amps of current (C) , its power (W) is given by W = V x C = 240 x 30 = 7200 Watts (= 7.2 kiloWatts)

To get the same power from a 120V supply the dryer would have to draw 7200 Watts divided by 120 Volts = 60 Amps. But that amount of current is over half the maximum current capacity of the usual 100 Amp mains supply panel that is fitted in a normal-sized house! In USA, Canada and other countries using the same 60Hz power system, houses are actually supplied with 240 Volts to the main power supply panel. This is split into two 120 Volt circuits which, between them, feed all the house's 110 Volt socket outlets. The common neutral wire is connected at the center point of the split 240 Volts on the main panel.

So it makes good sense to use the full 240 Volts for a powerful appliance such as a clothes dryer because then the current can be reduced to only 30 Amps. That is only about a third of the maximum current capacity available from the usual 100 Amp house mains supply panel. There are also serious issues to be considered such as the size of of the wiring - to carry current safely, without overheating, wiring would have to be much thicker to carry 60 Amps instead of 30 Amps - and the sizes of power breakers required to protect the circuit in the event of a fault developing. Faults can occur due to accidental damage or to breakdowns in several places around any electrical circuit:

* in the appliance itself (due to overheating from excessive weight of clothing, or build-up of fluff, or heating elements simply burning-out after many hours of use) * in the appliance's own cable and/or plug * in its wall socket outlet and/or

* in the wiring from the breakers on the main supply panel to the outlet.

Answer 3

The heat in gas dryers is from the burning of natural gas. The electricity is only needed to power the blower. The heat in an electric dryer is supplied from a large element that uses a lot of electricity and needs 220 volts to supply enough heat. With a gas dryer you only need 120 volts to turn the drum because the gas heats the air. With the electric dryer the electric heating element takes 220 volts to heat. Similar to an electric stove heating element.

Answer 4

Because at 110v the amp's would be twice the amps. Using the higher voltage you cut the amps in half. Thus if ya double the volts you 1/2 the amps. and vice versa. If ya 1/2 the volts ya double the amps. You pay electric bills for amps. the toaster is small enough it only uses a small amout of amps at 110v.

Answer 5

A toaster has a 1000 watt element while a dryer has a motor and an element of 4500 watts. To run the dryer on 120 volts would be very expensive.

Except for North America most have 220V 2 wire for everything, fed from a 460 volt 4 wire system.