Saturday, November 7, 2015

Circuit diagram of ceiling fan; Fault finding in ceiling fan

Ceiling fan is integral part of every house and Industry. In this article we discuss about wiring of ceiling fans and circuit diagram of ceiling fans.

Ceiling fan are having “Capacitor Start capacitor Run motor”. These motors have capacitor in series with starting winding. Capacitor used for this is electrolytic type. Due to this capacitor single phase get divided into two phases, due to this magnetic field is produced and due to which motor starts to rotate.

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Circuit diagram for ceiling fan is as shown below where capacitor is connected in series with starting winding.
Ceiling fan Circuit diagram

How to reverse the direction of ceiling fan?
Direction of Ceiling fan motor can be reversed connecting capacitor with running winding instead of starting winding. 
Wiring of ceiling fan:-
Ceiling fan connected to power supply through a switch and regulator.  Usually phase is rotated through switch and regulator and neutral is directly connected at ceiling fan. Fan regulator is used to control the speed of fan.
Ceiling Fan wiring

Faults in Ceiling Fan:-
There are two types of faults:-
(A)               Mechanical faults
(B)               Electrical Faults
A)     Mechanical faults:-
There are following Mechanical faults occur in fans:-
(i)                  Bent in shaft
(ii)                Bearing problem
Due to all above faults fan may not run properly or run very slowly.
B) Electrical Faults:-
(i) Main running winding get Open circuit/Short circuit.
(ii) Main starting winding get Open circuit/Short circuit.
(iii)               Capacitor get Open circuit/Short circuit.
(iv)              Earth Fault.
(v)                Fan motor rotate in reverse direction.
For (i) & (ii) faults types detection will be done through this method:-
Open/ Short circuit in winding can be detected by using Test bulb arrangement. Arrangement for the same is as shown below:-

Ceiling Fan Fault finding

If  bulb doesn’t glows then there  will  disconnection in the winding.
If bulb glows full then there will be short circuit in the winding.
If bulb glows very dim then there is no fault in the Winding.

For (iii) fault capacitor can be checked by using multimeter for it’s value if value is found low then capacitor will be changed. Usually capacitors used in Ceiling fans have 2.5 microfarad rating.
For (iv) fault earth fault can be checked by using multi-meter.
For (v) fault i.e. for reverse direction same can be changed by changing capacitor bank connection to other winding.

In Single Phase motors why There are more turns on running winding in comparison to start winding?:-
In Running winding no. of turns are kept higher than starting winding the reason behind this is to create phase difference in current in both windings to obtain required torque for rotation of motor.
In Start winding when we keep lower no. of turns than there will be less inductance and more resistance so current will be in phase with voltage. Now by keeping higher no. of turns in running winding we will obtain more inductance and lower resistance which will leads to current lagging behind voltage so we will obtain required phase difference.

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