Why we use capacitor in a fan?

Question

In light we just directly connect it to the supply.but in fan we use capacitor.why?is it possible to connect a fan like light?

Answer 1

There are two types of electric motor in common appliance use. They are Split Phase and Capacitor Start.

A Split Phase motor has start and run windings, both of which are energized when the motor is started. When the motor reaches about 75% of its rated full load speed, the starting winding is disconnected by an automatic switch.

A Capacitor Start (which sounds like the one you may have) has a capacitor in series with a starting winding and provides more than double the starting torque with one third less starting current than the split phase motor. Because of this improved starting ability, the capacitor start motor is used for loads which are hard to start. It has good efficiency and requires starting currents of approximately five times full load current.

Answer 2

we use capacitors in fans usually to smooth out the current

otherwise the fan would be highly variable as far as wind speed

also in an average household the voltage is AC which means it alternates flow direction every 1/60th of a second

(AKA 60 hertz)

Answer 3

More on what VIN said, yes you can have a fan without a capacitor, but it would be a really old fan.  I had one when I was a kid that if you turned it on it would just buzz until you gave it a push.  Those kinds don't have capacitors.

A capacitor is a high pass filter, but I doubt that is the reason for its use.

Answer 4

The capacitor is there for POWER FACTOR CORRECTION. Look it up!

Answer 5

single phase motor used for fans. it wont produce rotating magnetic filed which is required for rotating torque. if we provide a capacitor then phase angle will change which will produce rotating magnetic field.if u turn the fan blade by hand then the fan will rotate.

Answer 6

If the AC is contaminated with higher frequencies than 60HZ the cap is used to ground the higher frequencies to make the motor run cooler.

Answer 7

interpol if you must copy at least try to read it first

ALL single phase induction motors are split phase

1: there is capacitor start;  uses the capacitor to phase shift one winding in the stator (field) to provide starting torque when it gets up to speed a rotating switch cuts the starting winding and the capacitor out of the circuit and wont reset until the motor stops.

2: capacitor  run; uses the capacitors phase shift to start and run leaving the capacitor in the circuit all the time

note it is the phase shift that creates the rotating magnetic field to pull the rotor around

not all fan motors are split phase some small motors are like a DC motor

a capacitor is used in flurescent lights for power factor correction to offset the induction of the ballast