Single Phase Induction Motor
In this article on Single Phase Induction Motor, there is detailed information about Single Phase Motor. In which information about the types of single-phase induction motor, its working principle, its use and advantages, and disadvantages has been discussed.
Single Phase Induction Motor
The single-phase induction motor has one phase and neutral wire due to its working on one phase, it is called single phase. For example, in a three-phase motor, a 433 volt supply is given in three phases. Similarly, the motor rotates on 230 volts in a single phase.
The working principle of Single Phase Induction Motor is the same as that of Three Phase Induction Motor according to Faraday's Law. But rotating magnetic flux is generated in a three-phase motor. whereas, alternating magnetic flux is generated in a single-phase induction motor.
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Why single phase motor does not self-starting?
A three-phase motor is self-starting but a single-phase motor is not self-starting. It is made to be self-starting.
A rotating magnetic field is required for any AC motor to rotate. Which is possible only with two or more phase supplies. It is not possible in a single phase so it is not self-starting.
How does a Single Phase Induction Motor Self Start?
Single-phase supply has a 90-degree electrical angle, it has to be converted to 120 degrees. And that happens by converting from one phase to two phases. Special methods have to be used to divide a phase into two parts. Then the motor self starts.
How does a single-phase induction motor become self-starting?
As explained above, the single-phase induction motor is not self-starting. To make the motor self-starting, it can be temporarily converted into a two-phase motor while starting and this can be achieved by introducing an additional 'starting winding' also called auxiliary winding.
How does a single-phase motor start?
Single-phase motors work on the same principle as 3-phase motors except they are only run off one phase. From single-phase, it sets up an oscillating magnetic field that goes back and forth rather than a rotating magnetic field. This type of phase is often called the start phase or the auxiliary phase.
Why capacitor is used in a single-phase motor?
Some single-phase AC electric motors require a "run capacitor" to energize the second-phase winding (auxiliary coil) to create a rotating magnetic field while the motor is running. The Start capacitors briefly increase motor starting torque and allow a motor to be on and off rapidly.
Which starter is used in the induction motor?
star-delta starter
The star-delta starter is used in starting an induction motor by using 2 relays as the connector and the timer as the controller. 1 connector is used to provide the mains supply while the other connector controls the connection of the motor in star or delta connection.
Which type of capacitor is used in a single-phase motor?
Permanent-split Capacitor
The single-phase induction motor has only one capacitor which is connected in series with the starting winding.
Can a motor run without a capacitor?
Without the capacitor, the motor will not start automatically but without a capacitor, a flick on the shaft will make the single-phase motor run in either direction, provided that the main winding is operating as it should do.
What is the Purpose of the Capacitor used for Motors?
The purpose of the capacitor to create a poly-phase power supply from a single-phase power supply.
How does a capacitor start a single-phase motor?
The Capacitor Start Motors is a single-phase Induction Motor that employs a capacitor in the auxiliary winding circuit to produce a greater phase difference between the current in the main and the auxiliary windings. The name capacitor starts itself shows that the motor uses a capacitor to start.
What happens if you use the wrong capacitor?
If the wrong run capacitor is installed the motor will not have an even magnetic field and this will cause the rotor to hesitate at those spots that are uneven. The hesitation created will cause the motor to become noisy, increase energy consumption, cause performance to drop, and cause the motor to overheat.
Types Of Single Phase Motor
Single-phase AC motors are classified according to their self-starting process.
All single-phase motors have been given different names. This name is based on the method or process used to self starting the motor.
1) Induction Motor
2) Commutator Motor
3) Synchronous Motor
Some types of these motors are like this:
- Capacitor start motor
- Shaded pole motor
- Repulsion motor
- Resistance start motor
- Capacitor start capacitor run motor
- Permanent capacitor motor
- Universal Motor
- Commutator motor
Where is single phase motor used?
Single Phase Induction Motor is used in small machinery. Especially used for household appliances electrical equipment such as ceiling fans, table fans, washing machines, mixer machines, flour mills, refrigerators, drill machines, and motors used in water pumps.
Advantages of using single phase motor
1) The power supply is 230 volts, in which one phase and neutral are used. The power supply in our house is 230 volt, so there is no problem with supply.
2) Single Phase Motor Manufacturing gets cheaper due to low price.
3) Maintenance cost is also less than three phases AC motor.
4) Lightweight is small in size and due to less weight, its movement can be done easily.
5) Losses are also reduced due to reduced load current.
Disadvantages of Single Phase Motor
1) Single-phase motor is not self-starting.
2) Starting torque is also less in Single Phase Motor.
3) Its protection is almost nil. Protection is not effective in overload.
4) Speed changes with load in Single Phase Induction Motor.
Single-phase induction motor
Servo Motor
The main feature of Servo Motor is that it works on both AC and DC supply. Its construction is similar to that of a DC motor. It uses armature, field winding commutator, and carbon brush. Therefore, the starting torque is high.
Servo motor is used where high speed is required. This motor is rotating at a speed of more than about 3500 to 4000 rpm. All these are designed according to our needs. The speed of the servo motor is low at load and high at no load.
This type of motor is used in various household appliances. Such as Vacuum Cleaner, Mixer Machine, Sewing Machine, etc.
Shaded Pole Induction Motor
Shaded Pole Motor is a self-starting single-phase induction motor. The stator of this type of motor has salient poles. The field winding is done on the sloping pole. The pole is shorted with a copper ring. And it is excited by a single-phase ac supply.
It consists of main winding and shaded pole winding. The main winding acts as the primary and the shaded winding of the transformer as the secondary.
The capacitor is not used for starting in a shaded pole motor. A shaded coil is placed on top of a shaded pole.
The shaded pole motor rotates in one direction. It does not change the direction. Comes in small ratings. Power loss is high. The power factor is also low.
It is used in small machines like small fans, toys, hair dryers.
Universal Motor
Universal motors have both field winding and armature winding. The series-wound is a DC motor only that can run on both AC and DC supply.
This type of motor is used for low capacity and high starting torque. Mixer machine, grinder machine, fan, sewing machine are used.
We can use Universal Motor in both AC and DC supply. Speed up to 3000 thousand rpm can be found. It can operate even with load.
Repulsion Induction Motor
Repulsion means driving away. As negative and negative are run away from each other it is called repulsion. But when negative and plus come closer to each other, it is called attraction.
The repulsion motor is driven by an alternating current AC supply. Stator winding, armature winding, commutator, and brushes are used in this type of motor.
In this, both the brushes are shorted against each other with resistance.
A repulsion motor is used for higher starting torque and higher speed. In this, speed and torque can be controlled by adjusting the position of the brush. There is variation in speed with the load.
Starting and maintenance cost is high.
In this article on Single Phase Induction Motor, there is information about Single Phase Motor. Hope this will be helpful for you. If you have any queries related to this then you can write me on my social media accounts.
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