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Do electric fans consume the same amount of electricity when operated at different speeds?


Date: 13 Sep 2016    Group: Science and Technology    Category: Technology   

The electric fans come with a regulator to increase or decrease its speed. Many people say that the electric fans consume the same amount of electricity whether operated at a slow speed or at the full speed as the resistance element provided inside the regulator consumes the electricity when operated at a slower speed. Do electric fans consume the same amount of electricity when operated at different speeds?
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Author: Alok Kumar    15 Sep 2016      Member Level: Silver     Points : 6  (Rs 6)    Voting Score: 0

The regulator, which comes to regulate the speed of fan is of different types. One type, which uses potentiometer kind of thing and regulate the speed by dropping the voltage across resistances kept in series of fan.
For different speeds, different sets of registers are used in series with fan. Thus for more resistors in series, more voltage will drop in resistors and lesser voltage will drop across fan. This lesser voltage across fan (say 150 V in place of standard 230V) will reduce the fan speed.
In such type of regulator electricity consumption will be equal at all speeds, as same power loss will be there in all cases. Voltage drop across resistors will generate heat inside regulator. These types of regulators were rarely used now.
Now a days different type of regulator is used which uses triac as regulator. It controls the flow of current by changing the firing angle. Here current is reduced, therefore power consumption is less. Changing of firing angle is basically limiting or chopping off the waveform by limiter or zero detector and thus reducing the average voltage to the fan and reducing its speed. Power is the product of current and voltage. Thus by reducing current and voltage we reduce the consumption of electricity.
Therefore, we can conclude that the consumption of electricity does not change at different speed of fan if we use old resistor type of regulator. But by using triac type of regulator electricity consumed at different speed is different and for lesser speed we have to spend less electricity.



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Author: Partha Kansabanik    15 Sep 2016      Member Level: Diamond     Points : 3  (Rs 3)    Voting Score: 0

Earlier days, the regulators used in electric fans were resistors. The regulators used to resist flow of electric current causing less speed, when the regulators functioned at higher level. There was no change in flow of electricity. So, in case of electric fans where old type of regulators are used, the consumption of electricity is always same irrespective of the speed of the fan.

However, nowadays a new type of regulators is being used in electric fans. It controls the flow of current. In case of electric fans where these new regulators are being used, consumption of electricity is different at different speed.



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Author: Sheo Shankar Jha    16 Sep 2016      Member Level: Gold     Points : 4  (Rs 4)    Voting Score: 0

Earlier, the function of the resistor was to restrict the flow the electric - current. More is the resistance employed, lesser will be voltage and hence less will be the current flow. But in that way, the power - consumption could not be reduced since because of higher resistors, there was wastage of energy in the form of heat. In case of employment of less resistance, the entire current offered the maximum power to operate the fan in full speed.
So, we could conclude that speed - variation by applying different resistors provided the variable speed but the power consumption was constant in all the cases.
With the advent of new type of regulator in the market, the consumption of current is directly proportional to the speed of the fan and hence, lesser is the speed, lesser is the power - consumption.



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Author: NK SHARMA    20 Sep 2016      Member Level: Gold     Points : 4  (Rs 4)    Voting Score: 0

The five stage voltage regulator regulate the speed of fan by dropping the voltage across registers kept in series inside the regulator. For different speeds, different sets of registers are used in series with fan. If more value of a resistor in series, the more voltage will drop across the resistor. If less value of register, less voltage drop across register. This less voltage across the registers will reduce the fan speed.The electricity consumption will be equal at all the speeds because voltage drop across resistors will generate heat inside regulator.


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