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 used in low-power applications where a simple and cost-effective motor is used. Its name is due to shading coil designs that take a rotating magnetic field in the motor to operate there we will cover different parameters of shaded pole motors and related parameters. 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: it is a static part that has main winding and shading winding. The shading coil is a small copper wrapped over the surface pole.
- Rotor: Rotoeris cylinder shape of iron or aluminum that is configured on the motor shaft.
- 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.
Shaded pole induction motor
A shaded pole induction motor is a single-phase induction motor with a magnetic field generated by the main winding and shading coil. The shading coil is single-run wiring or bar configured over each stator pole. When current flows through the main winding, it casues a field that rotates over the stator. Shading coil also has current bit some quantity delays current.
The delay is due to the field produced by the shading coil rotating slower than the field produced by the main winding. Difference speed of two fields generated by rotating torque that starts motors.
Shaded poles are a simpler and less costly type of expensive single-phase induction motors. it is used for fans, small appliances, and toys.
features of a shaded pole induction motor:
- single-phase motor.
- main winding and a shading coil it has
- The shading coil is a single-turn copper ring or bar that is positioned around a portion of each pole of the stator.
- The shading coil produces a rotating magnetic field slightly slower than the magnetic field generated by the main winding.
- This difference in the speed of the two magnetic fields produces a rotating torque that starts the motor.
- Shaded pole motors are the simple and less expensive ingle-phase induction motors.
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 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 result starting torque produced due to rotating magnetic field.
Shaded pole motor diagram
Here is a diagram of a shaded pole induction motor:
The motor’s stator has two poles, each with a main winding and a shading coil. The main winding is attached to the power supply, and the shading coil is configured with the main winding through a capacitor. The motor is the squirrel cage rotor. Squirrel cage rotor is made with a series of copper bars that are short-circuiting at every end. When the motor starts, the field from the stator induces a current in the rotor bars. These current-generated fields make a connection with the stator field, resulting in rotor rotation.
Why Is It Called a Shaded Pole Induction Motor?
A shaded pole induction motor is known as a shaded pole motor due to the shading coil placed around a portion of each stator pole. The shading coil is a single-turn copper ring or bar attached to the main winding through a capacitor.
The name shaded pole comes from the shading coil shades off the pole, which results in the magnetic field in that part being weaker. This weaker magnetic field rotates slower than the stronger one in the unshaded part 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
Feature | Synchronous Motor | Shaded Pole Motor |
---|---|---|
Speed | Synchronized with the rotating magnetic field of the stator winding | Not synchronized with the rotating magnetic field of the stator winding |
Power factor | High | Low |
Starting torque | High | Low |
Efficiency | High | Low |
Cost | High | Low |
Applications | Clocks, electric generators, timing devices, traction motors | Fans, machine tools, blowers, pumps, |
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?
Faqs
- What is a shaded pole motor?
A shaded pole motor is a single-phase induction motor has copper ring or bard surrounding each pole. it gernated rotating field that resulted motor to start and run
- What are the advantages of shaded pole motors?
Its design is simple, self start motor, not need starting capacitor. Rugged and reliable
It used in fans, pumps, and small appliances.
- What is a capacitor and shaded pole?
A capacitor is a device that stores electrical energy. A shaded pole motor uses a capacitor to start the motor. The capacitor is connected in parallel combination with the shaded pole winding. When the motor is turned on, the capacitor charged and then discharges, making strong magnetic field that helps to start the motor.
- Which of the following are the features of a shaded pole motor?
Single phase stator wiring
Low efficiency
Self start motor
Rotor is squirral cage
Shaded winding in evey pole
- What is the principle of a shaded pole?
- Power is given to stator flux produced in the pole. This flux induces a voltage in the shading coil. It works as the secondary winding. By Lenz law current direction must be in reverse of fluxing in the coil
- What is the efficiency of a shaded pole motor?
it has low efficney about 5 to 35%. Its low due to power losse in shading coil
- What is the disadvantage of a shaded pole motor?
Direction not changed
Noisey
Less efficiecny
Les power
- Does a shaded pole motor have only one winding?
shaded-pole motors have one main wiring and no starting einding or switch. In other indcution motor rotating pat is squirlla cage rotor
- What is the direction of a shaded pole motor?
The direcion of rotation form unshaded side to shaed side of poles. As phae angle between shaded and unshaded part is small, shaded poles motor gernated samll starting torque relative to torque at full speed
- How many windings does a shaded pole motor have?
A shaded pole motor has 2 windings: the main winding and the shaded pole winding. The main winding is used for creating the magnetic field, and the shaded pole winding for creating a rotating magnetic field that helps to start the motor.
- Why is the efficiency of a shaded pole motor low?
The efficiency of a shaded pole motor is less larger amount of power is lost in the copper losses of the shading coil
- Will a shaded pole motor rotate?
This motor rotaes in one direcrion and reverse is not possible. Rotation direction is from unshaded pole to shaded pole
- Are shaded pole motors synchronous?
No, shaded pole motors are not synchronous motors. Synchronous motors rotate at a constant speed that is synchronized with the frequency of the power supply. Shaded pole motors do not rotate at a constant speed. The speed of a shaded pole motor based on the load that is connected to it.
- What is the function of a shaded pole induction motor?
The function of a shaded pole induction motor is to tansform electrical energy into mechanical energy. The motor does this by rotating a shaft that is attaching to a load. The rotating shaft turns the load,like fan blade or a pump impeller.
- Why do motors have to reverse pole direction?
Reversing the polarity of DC motor’s magnetic field can be used stop, to slow down,, or vary the direction of the motor’s spinning force