What is shaded pole induction motor

shaded pole induction motor is the type of single phase induction motor . Since it is self started motor, so it is also known as self starting single phase induction motor.

in this type, single phase induction motor or shaded pole motor one pole is shaded by the copper ring. The copper ring is also known as shading ring. Where copper ring act as secondary coil or secondary winding.

The shaded pole induction motor rotates only in one direction . Reverse action in shaded pole induction motor is not possible. Read more for detail explanation.

Construction of shaded pole induction motor

the shaded pole induction motor can be designed of two or four poles. The speed of the motor is inversely proportional to the number of poles that are used in the motor. It means that if the number of poles are more then a speed of motor will be less and if the number of poles are less in the motor, then the speed of motor will be high .

Stator

salient, pole stator is used in shaded pole induction motor meaning of salient is magnets are projected towards the armature of the motor and each pole of the motor is excited by the exciting coil .
The copper ring makes a loop or we can say it look like loop that is known as shading coil.

stator of shaded pole induction motor has laminated pole. Meaning of lamination is various thin strip attached together to make stator.

lamination increases the strength of the stator as well as it reduces the eddy current loss and Stator slots are constructed at some distance, apart from the edge of the poles.

Rotor

a squirrel cage rotor is used in the shaded pole induction motor. In a squirrel cage rotor bars are skewed at an angle of 60°. We constructed a skewed bar for the greater torque.

The construction of the motor is very simple, or we can say it is easy to construct because it has not any type of commutator , carbon brush, collector, ring, etc.

the shaded pole induction motor, don’t uses any centrifugal switches that’s why the chances of failure of the motor are less .

centrifugal, which is the type of electrical device that starts operating by the help of centrifugal force and centrifugal force generated by the rotating shaft, and it is also used for the controlling the speed of the shaft.

working of shaded pole induction motor

first of all we give single phase AC supply to the stator winding where main winding is placed so due to AC current in main widening alternating magnetic flux produces. We consider as a main flux and when main flux cut the copper ring at shaded portion of the stator pole then EMF induced in the copper ring according to the faradays law of the electromagnetic induction.

According to this principal, whenever. Changing magnetic flux cuts the stationary conductor ,Then EMF induce in the conductor. That’s why here EMF is inducing in the copper ring. And current circulated because copper ring remain short circuit. Here it is rounded, so it is completing the circuit . So due to current in the copper ring another magnetic flux produces around the copper ring that we consider as shaded flux .

Now we have two fluxes main flux, and shaded flux. Suppose main magnetic flux is the (Øm) and shaded flux is the (Øs) , shaded flux (Øs) will oppose the main flux (Øm) from Lenz law .

When both magnetic flux opposes to each other then both magnetic field displaced by some angle that will less than 90° but due to phase displacement rotating magnetic field produces in the gap of stator and rotor .

So due to that rotating magnetic field torque acts on the rotor in tangential direction and rotor starts to rotate in the direction of shaded portion .
here, pole of motor play very important role because pole of the motor is inversely proportional to the speed of the motor . If number of pole is less then speed of motor will high and it’s vice versa .

Important points : there are different applications of shaded for induction motor like it is used in toy motor, tape recorder, fan, hair dryer and film projector .. etc

since tape recorder and hair dryer this type of equipments are very small in size that runs on single phase AC supply and we have requirement of a small size single phase induction motor that’s why we designed shaded pole induction motor that is small in size which can easily install in this type of a small equipments. As we know there are different type of single phase induction motors like capacitor start capacitor run motor, Capacitor start induction motor, split phase motor etc but due to large in size this type of Motors are not used in small equipments like hair dryer and tap recorder.

so shaded pole induction motor is the best option that can be easily installed in a small size equipment to run with single phase AC supply.