Answer / ravi693

Regulator is nothing but a series circuit of resistances.
Let regulator has three points.
At point 1, All the three resistances are in ciruit. The
eq. resistance increase, current decreased & speed
decreased.
At point 2, only two resistances are in circuit. The eq.
reistance is decreased, current increased speed of fan is
increased.
At point 3, only one resistance in ckt. The eq. resistance
is again decreased, current increased. speed of fan is
again increased.

Answer / prabakaran

Fan speed is controlled only by input voltage applied to
fan winding not current.

Voltage controlled by the regulator by adding resistance to
circuits

Answer / ashwin

Yes we can control the speed of fan by varying the voltage. Voltage varies in series connection of resistance. In olden days they use to connect resistors in series and when we turn the regulator knob, we can add more resistance or remove resistance in series thereby reducing or increasing the voltage input to the fan. Nowadays instead of using external resistors they are using metal's or material's internal resistance. (I don't know about the disc material. It will be somewhat like a metal alloy.) A roller or ball will move over a metal disc. The position of the ball on the disc will determine the total resistance included in series(this is because of the internal resistance of the metal). They are using this technique in smooth regulators.

Correct me if I am wrong.
My email id is: tarus_cool@yahoo.co.in

Answer / nilkanth.

when we decrese the fan speed then we decrese regulator by
one step then resistance in the circuit will also increse
then fan speed is decrese

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