Hi guys, welcome to the new post. Here we will discuss What is a Shaded Pole Motor : Construction, Working & Its Applications A Shaded Pole Motor is a single-phase induction motor and a rating of less then 0.05 HP is common since it has a simple structure. This motor is self-starting motor with one pole shaded with a copper ring. it is simple, low cost, and less maintenance motor. So let get started with What is a Shaded Pole Motor
Shaded Pole Motor Definition
- The shaded pole motor is a type of AC single-phase motor. The shaded pole motor is a small motor having two of four poles, that come with auxiliary winding composed of a copper ring or bar covering a part of every pole for the generation weak magnetic field.
- If a single-phase AC supply is connected with stator winding, and due to shading to poles rotating magnetic field is produced.
- Auxiliary single-turn winding is known as a shading coil.
- Current produced in this winding through the magnetic field generated 2nd electrical phase with a delaying phase of magnetic flux varying for the pole which has features to offer 2 2-phase rotating magnetic field.
- The direction of rotation is due to the unshaded side to the shaded side of the pole. As the phase angle between the shaded and unshaded part is small, the shaded pole motor generated a small starting torque as compared to the torque for full speed.
- Shaded pole motors of asymmetrical type are reversible by disassembly and flipping over stator through some same motors come with small, switch shortly auxiliary windings of thin wire then thick copper bars and can be reverse electrically.
Shaded Pole Motor Construction
A Shaded Pole Motor comes with these main components:
Stator:
- The stator comes with primary poles normally have 2 to four poles, that come with their own exciting windings. Each pole part of the core is configured with a copper coil, making a closed look that is called a shading coil. The laminated poles come with slots that are cut across the lamination of the pole. Slots are configured 1/3 of the way from the edge of the pole. Short circuit copper is configured in slots, making part as shaded poles remaining part of the pole is unshaded.
Rotor:
- This motor comes with a squirrel cage rotor. Rotor bars are configured at an angle of 60 degrees in slanted form. A slanted structure is made for optimizing torque and reduces dip at the acceleration phase.
End Rings:
- These are short-circuited rings configured at both rotor ends.
Main winding:
- The main winding is the primary winding of the motor. Here power source connected
Shading coil:
- it is a single-turn copper ring or bar placed around each pole of the stator. It is attached to the main winding through a capacitor.
Capacitor:
- The capacitor is used to delay the current in the shading coil, which results in the magnetic field produced by the shading coil rotating slower than the magnetic field of the main winding.
Working Principle of Shaded Pole Motor
- When the supply is connected with the main winding field is produced in the stator.
- The shading coil is connected with an asymmetrical structure over the pole face. It casues part of the pole high magnetically conductive than the rest state
- When AC volts change shading coil induces an eddy current in the shaded part of the pole, which causes a small time lag in field creation.
- This time lag field is not properly configured with a pole, generating a rotating field.
- The rotating field interacts with the rotor and starts moving in the direction of the rotating field.
Working of Shaded Pole Induction Motor
The working principle of a shaded pole induction motor is simple. If single-phase AC is given to stator winding, it generates a stator magnetic field. This magnetic field connects the shading rings. As a result, EMF is induced in shading rings.
.Shading rings are created with high conductive materials copper and make closed loops.
The current started moving in a shared ring due to induced EMF. This circulation current also generates a magnetic field that hinders the magnetic field. As a result, there is space displacement created in the shaded part and the unshaded part of the motor.
The space displacement between the main field and the shaded field are at 90 degress.
Motor generated rotating magnetic field since time and displacement between main field and shaded part field. The rotating magnetic field rotates from the unshaded part to the shaded part of the motor.
In a result starting torque is produced due to the rotating magnetic field.
Shaded pole motor diagram
Here is a diagram of a shaded pole induction motor:
It has two poles on the stator, and each stator has main winding and shading winding.
The main winding is connected with the power source and the shading winding with the main winding through the capacitor.
The rotor in the motor is squirrel-age type. This rotor is made with the use of copper bars in a series combination that is short circuit at the ends.
If motor stars field from stator induces a current in rotor bars. Curreng-generated fields connect with the start field and rotate the rotor
Why Is It Called a Shaded Pole Induction Motor?
It is called a shaded pole since single-phase induction motor comes with salient or projected poles.
These poles are shaded with a copper band or ring that is inductive. Poles are divided into two unequal halves. The smaller part has a copper band and is known as the shaded portion of the pole.
Shaded Pole Induction Motor of Characteristics
- its construction is simple and easy to design
- it has a low starting torque and power factor
- its featues is that no reverse of direction is possible
- it is a less costly motor
- it is a self-start motor
- it is a small size, about 40 watts or less
Applications of Shaded Pole Induction Motor
- It is used in devices that need low starting torque.
- It is used in exhaust fans, table fans, etc
- This motor is used for starting an electronic clock
- It is used in refrigerators and Air conditioners for driving cooling mechanisms.
Why is the Shaded Pole Induction Motor suitable for low power rating?
Shaded poles are used for power applications due to low starting torque and efficiency ratings. Due to less starting torque shaded poles are made in small sizes from 1/20 to 1/6 hp.
How does the Rotating Magnetic Field Produce in a Shaded Pole Induction Motor?
Due to excitation curent produced in shading winding. The field from the shading winding current is in quadrature to the excitation. it rotates filed in from the middle of the pole to the shaded edge of the pole, causing the rotating field to pull the rotor round.
Advantages of Shaded Pole Induction Motor
- Self-starting:
- Simple design:
- Low cost:
- Rugged and reliable:
- Low maintenance:
Disadvantages of Shaded Pole Induction Motor
- It has a low starting torque
- There is no reverse rotation exists in this motor
- It has a poor starting power factor
- its efficiency is low
What is Synchroscope, Working, Features & Applications
Introduction to Synchronous Motor, Working, Types, Construction, Advantages & Applications
Difference between Induction Motor and Induction Generator
Synchronous motors vs Shaded Pole Motor
The shaded pole motor is a single-phase motor. Shaded winding is a technique for starting a single-phase motor.
The synchronous motor is a complex polyphase motor with a round rotor getting power with DC through slip rings that are from exciter moving on the shaft.
The exciter is used as a DC motor to wind the synchronous motor up to speed, and then the starter makes a connection with the supply and the excitation circuit closes.
What is a shaded-pole motor used for?
What is the difference between shaded poles and PSC motors?
What is the speed of a shaded-pole motor?
Does a shaded-pole motor use a capacitor?
How does a shaded pole motor start?
Are shaded pole motors synchronous?
- What is Circle Diagram of Induction Motor – Definition, Construction & Its Parts
- Different Types of Induction Motor and Features
- Difference between Induction Motor and Induction Generator
- Difference Between Slip Ring and Squirrel Cage Induction Motor
- Solid State Induction Motor Drives
- Difference between Synchronous Motor & Synchronous Generator
Faqs
- What is a shaded pole motor?
The shaded pole induction motor is single phase AC eletric motor used for simple and reliable design. These motors used in fans, refrigerators, and some small pumps
- What are the advantages of shaded pole motors?
It is self starting, motor without use of extra starting process. It is best for small devices.
Less maintenance needed and high relaible. It is less weight and compact size
- What is a capacitor and shaded pole?
A capacitor is a device that stores electrical energy.
Shaded pole motor is type of AC single phase induction motor also called single phase induction motor, just connection with single voltage line and external capacitor needed to run motor
- Which of the following are the features of a shaded pole motor?
- It gemerated starting torque that is half of torque on full load.
- It is less efficiency due to power losses in shading coil.
- it used in small devices such as fans.
- Based on shaded coil position direction rotation varie
- What is the principle of a shaded pole?
- If power is connected to the stator, flux in the main part of the pole induces a voltage in the shading coil, which works as transformer secondary winding. As the current in the secondary winding of the transformer is out of phase with the current in the primary windings
- What is the efficiency of a shaded pole motor?
The efficiency of shaded pole inductioni motor is low in range of five to 35 percent. its efficiency is low due to power losses in shading coil.
- What is the disadvantage of a shaded pole motor?
It has low efficicny with constant power losses in shading coil.
it has limited torque that makes it not good for heavy loads.
it is not able to reverse direction of rotation without modification of design.
its less power factor limted uses.
- Does a shaded pole motor have only one winding?
This motor comes with single winding with no capacitor or starting winding switch, make it reliable and less cost. Larger and latest types can comes with multiple windings but electrically has one and capacitor can be used
- What is the direction of a shaded pole motor?
The direction of rotation from unshaded side to shaded side of pole. As the phase angle between shaded and unshaded part is smal, shaded pole motors genrates small starting torque relative to torque at full speed
- How many windings does a shaded pole motor have?
Shaded pole motor comes with main winding connected with single phase supply. With that has permanently short circuit winding ahead of main winding in direction of rotation. That 2nd winding called shading coil
- Why is the efficiency of a shaded pole motor low?
It has less efficiency due to power lossses in shading winding
- Will a shaded pole motor rotate?
Shaded pole motor rotates in one direction and reverse motion of motor is not exists. Diretion of rotation of magnetic field is from (unshaded) pole to the shaded pole
- Are shaded pole motors synchronous?
Shaded pole motor is single phase motor, shaded pole winding is starting single phase motor. The synchronous motor is complex plyphase motor with wound rotor feeded with DC slip sings from exciter that operated on shaft
- What is the function of a shaded pole induction motor?
In shaded pole induction motor, shaded winding generates weak rotating magentic field and not constant magnitude. So these are small rating of 20 watts. This motor can used for toys, hair dryer, fans etc
- Why do motors have to reverse pole direction?
As the magnetic field winding is pushing or pulling magent on spindle, motor reverse direction when curent reverses. According to Faraday’s left hand rule if magnetic field direction chagnes, then direction force changes