Synchronous speed is the speed of rotation of the magnetic field in a rotary machine, and it depends upon the frequency and number poles of the machine. Show related SlideShares at end. The working principle and construction of Capacitor start inductor motors and capacitor start capacitor run induction motors are almost the same.
These are used in low power applications and widely used in domestic applications as well as industrial. This motor is used in applications, such as compressor, refrigerator, etc. Single phase induction motors are extensively used in low power applications such as domestic appliances as mentioned above. However, if the rotor of a single phase motor is rotated in one direction by some mechanical means, it will continue to run in the direction of rotation.
This results the motor to run for many years with no cost and maintenance. Since this shaded portion is short circuited, the current is produced in it in such a direction to oppose the main flux. So the field moves from one side of the pole to another side of the pole. These poles are shaded by copper band or ring which is inductive in nature.
Speed control of induction motors are difficult. Leave a Reply Cancel reply Your email address will not be published. Currents The field structure has non-salient pole construction. Also, the power factor of these motors is poor.
In this, the auxiliary winding and capacitor remains in circuit permanently and produce an approximate two phase operation at rated load point. The motor uses a squirrel cage rotor, which has a laminated iron core with slots. The smaller portion carries the copper band and is called as shaded portion of the pole.
This can result in reducing the effort needed for maintenance. These are of two types, kammertheater karlsruhe singleparty squirrel cage and slip ring motors. The auxiliary or starting winding is made highly resistive whereas the main or running winding is made highly inductive. You do not have the permission to view this presentation.
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The torque-speed characteristic is same as that of a three-phase one, having both starting and also running torque. These are used in compressors, refrigerators, air conditioners, conveyors, ceiling fans, air circulators, etc. What is an Induction Motor? The construction of induction motor is very simple and hence maintenance is also easy, resulting in low maintenance cost.
Mechanical losses are more and having low efficiency. These two windings are connected in parallel across the supply. It is wound for a distinct number of poles. It has only one capacitor in series with starting winding.
The single phase motors are simple in construction, cheap in cost, reliable and easy to repair and maintain. The stator of the shaded pole single phase induction motor has salient or projected poles. In the second case, the motor is a balanced two phase one, the two windings having same number of turn. Those are split phase, shaded pole and capacitor motors.
Hi Muskan Glad to hear that, partnervermittlung kanada and thank you so much for your feedback. Machine tools Suggestions or difficulties are most welcome at vijayraskar yahoo. The purpose behind this name is the anchor shape of the rotors used within quite early electrical devices.
You can change your ad preferences anytime. An Overview of Armature Reaction. Hence there exists a phase difference between these currents and thereby phase difference between the fluxes produced by these currents. In order to view it, please contact the author of the presentation.
Applications of Induction Motor
Types of Single Phase Induction Motors
- We already know that single phase induction motor is not self starting because the magnetic field produced is not rotating type.
- The shaded-pole principle is used in starting electric clocks and other single-phase synchronous timing motors.
- Induction motor might be worked as either motors or generator.
- There are basically two types of induction motor.
- This part where shading coil is placed is generally termed as shaded part of the pole and remaining portion is called as un-shaded part as shown in figure.
- The rotating magnetic field is produced when there are minimum two alternating fluxes, having a phase difference between them.
This motor consists of two capacitors of different value of capacitance for starting and running. Since we can assume the pulsating magnetic field as two oppositely rotating magnetic fields, there will be no resultant torque produced at the starting, and hence the motor does not run. If the phase difference is more, starting torque will be more.
Applications of Polyphase Wound Rotor Induction Motors
The induction motor always runs at speed less than its synchronous speed. It has a cage rotor and stator. This motor uses entirely different technique to start the motor as compared with other motors so far we have discussed now. Presentation Description starting methods. Capacitor start capacitor run induction motor two value capacitor method.
So in all the above methods or say types of induction motors, the additional flux other than main flux should have a certain phase difference with respect to main or stator flux. An induction motor is the most modest electrical machine from constructional point of view, in the majority of the cases. As mentioned above that, due to the rotating magnetic field of the stator, the induction motor becomes self starting. So, in capacitor start inductor motor and capacitor start capacitor run induction motor we are using two winding, single the main winding and the starting winding. This is the key strength of these motors.
1phase induction motors
Each slot carries a copper, aluminum, or alloy bar. The schematic arrangement of this motor is shown in figure below. Due to the capacitor, the inrush currents are reduced in this motor. This non uniform distribution of flux causes magnetic axis to shift in the middle of the non shaded part. The stator is a stationary part and it has laminated construction, which is made up of stampings.
This is one of the most widely used types of single phase induction motors. Aluminium bars are moulded on the slots and short-circuited at both ends with a ring. Rotor voltage is induced in the rotor windings rather than being physically connected by wires.
- It has salient poles on the stator excited by single phase supply and squirrel cage rotor.
- So the rotating magnetic field has the same phase difference which will make the rotor to move.
- Because of that, the rotor will feel a torque which will make the rotor to rotate in the direction of the rotating magnetic field.
- This part is of the pole is known as shaded part.
It is logical that the least expensive, most reduced upkeep sort engine ought to be utilized most regularly. Hence, using two capacitors, the performance of the motor improves both at the time of starting and then running. The rotor flux will be lagging in respect of the stator flux. The phase difference between these two fluxes produces resultant rotating flux. Does a question arise as to how it works?
Single Phase Induction Motor Speed Control
Due to the inductive nature, current through main winding lags the supply voltage by a large angle while the current through starting winding is almost in phase with voltage due to resistive nature. Because of its simple construction. The second one is to be rated for continuous duty, as it is used for running. On the other hand, they are fundamentally used as induction motors.