Specifications

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angle between starting winding and running winding current. So Capacitor is used produce
required phase shift between these current and hence to produce high starting torque and will
be connected in series with starting winding. Normally in ceiling fan, an electrolytic capacitor of
2.5 mF±5% will be used. The capacitor and starting winding will be in circuit during running also
and hence improve the power factor. So this motor will also called as permanent capacitor
induction motor. Rotor employs 1-phase squirrel cage winding.
2. Blades: The blades are made of sheet steel or aluminum sheets. Aluminum blades are
lighter than steel sheet plates and also improve the efficiency of the fan. The ceiling fans normally
have 3 or 4 angular blades. The four blade fan gives more air circulation as compared to three
blade fans. The blades are 120
o
mechanically apart and may be curved at an angle of 10
o
.
3. Blade flanges: Alternatively called as blade irons, blade arms or blade holders. These are
metal arms which connect the blades to the motor.
4. Canopy/Switch Cup: There are two canopies top and bottom, made of metal cylinder,
placed along suspension rod. Top canopy is mounted such that it covers the hook, nut, and bolt.
Bottom canopy is mounted below and in the centre of the fan’s motor. This is used to conceal
and protect various components, which can include wires, capacitors and switches. On fans
that require oiling, the bottom canopy often conceals the oil reservoir which lubricates the bearings.
5. Ball bearing: Friction free and noise free movements of rotating parts are ensured by providing
ball bearing between rotating and stationary parts. The ceiling fan may have single or double ball
bearings. The bearings made of high quality steel are regularly greased with superior quality for
its long life and noise free operation.
6. Suspension rod/Down rod:
It is made of rigid galvanized steel pipe of appropriate length and diameter. This metal pipe
is used to suspend the fan from the ceiling. One end of the pipe is bolted or screwed at the place
specially made on the motor body to receive the suspension rod. The other end of the suspension
rod is attached to two plates, to from a “U” shaped joint, with the help of a nut and bolt (with
additional lock nut). The “V” shaped end of the rod is further attached with the ceiling hook with
the help of bolt and nut with additional lock nut and split pin to eliminate chances of disconnection
at any stage.
Fig.13.3 - Resistance type Fan regulator
7. Speed regulator: It is used to control the
speed of the fan. The speed of the fan can be
varied by changing the applied voltage. The
most common method to vary the applied
voltage is i) by tapped field resistors and ii) by
tapped series inductors. Nowadays thyristor
based electronic type regulators mostly used
compared to above mentioned electric types.
The electronic fan regulator is fault-free, has long life and more efficient as compared to electrical
fan regulators. The schematic diagram of a fan with resistance type regulator is shown in Fig.13.3