Single Phase Induction Motor, Working, Construction & Applications

Hello friends, I hope all of you are doing great. In today’s tutorial, we are gonna have a look at the Single Phase Induction Motor. Nowadays in our houses and in some small industries, single-phase power is used instead of the 3-phase. As the single-phase networks are less costly then the 3-phase system and most appliances used in our homes, shops, and offices are designed to operate on the single-phase supply.

To use single phases input supply single-phase induction motor is used, these motors are less costly, easy to repair, and their reliability is higher. In today’s post, we will have a look at its working, construction, types, parts, and applications. So, let’s get started with an introduction to the single-phase induction motor.

Single-Phase Induction Motor

• A Single-ø Induction Motor comprises a single-ø winding that wound on the stating portion of the motor and its rotor consists of a cage winding.
• A revolving magnetic field is created when we provide single phase input at the stating part of the induction motor.

• In our society mostly single-ø techniques are used instead of 3 phases.
• As, the single-ø system is less expensive than the 3-phase system, and our home appliances are also designed to work on the single-phase system which also enhances its importance.
• The single-ø induction motor is easy to design, less costly, dependable, and can be easily repaired.
• As it has many benefits, so it’s used in fans, washing machines, juicer machines, and some other types of machinery.

Parts of Single Phase Induction motor

• There are many parts of the induction motor, but its main parts are the two first one is rotor and the other is the stator.

Stator of Single Induction Motor

• It is the stating part of the induction motor in this portion stator winding is wound and input supply terminals are also made on this part.

Rotor of single-phase Induction Motor

• The rotor of the induction motor is its rotating part which rotates in the magnetic field. There are two types of rotor of single phase induction motor first one is wound and the other is squirrel cage rotor.
• Let’s discuss both types one by one.

Squirrel Cage Rotor of Single Phase Induction Motor

• This type of rotor comprises a sequence of conductor bars which are arranged in a cylindrical shape structure in the different slots.

• All these are connected with the slip ring on both sides. This assembly is said to be a squirrel cage because its shape is like a squirrel.

 

Working principle of Single Phase Induction Motor

• Single-phase induction motor works on the principle of Faraday law electromagnetic induction which says that the rate of change of flux is equaled to emf induced.

EMF= dΦ/dt

Types of Single-phase Induction Motors

• There are many types of single-phase induction motors, these types are classified according to the starting processes of a single-phase induction motor. These main types of induction motors are described below.

• • Split-phase Induction motor
  • Shaded-pole Induction motor
  • Capacitor-start capacitor-run Induction Motor
  • Permanent-split capacitor Induction Motor
  • Capacitor-start Induction Motor

Split-Phase Induction Motor

• This type of induction motor is also named as a resistor start motor.
• It comprises a cage rotor and its stating part consists of two windings. The first one is known as main winding and the other is starting winding which is also named as auxiliary winding.
• These windings are connected at an angle of ninety degrees. The main winding has low resistance values.
• As the phase difference between its main and auxiliary winding’s current is less so these motors provide less starting torque.
• So, these motors used for such load that needs less starting torque.

Capacitor-Start Induction Motor

• This type of induction motor produces a higher starting torque about three to four times than the full load torque.
• For higher starting torque the capacitor values should be higher, and the values of stating winding resistance should be less.
• In this motor due to the capacitor, the current at auxiliary windings leads the voltage.
• Due to this phase alteration, the main and auxiliary windings current will increase and it will also enhance the value of the initial torque.

• The starting torque of these motors is almost three hundred percent of the torque value when a load is connected. But its P.F. is very low in the case of the rated load and speed.

Two-Value Capacitor Motor

• This induction motor consists of a cage type of rotor and its starting portion has 2 windings which are known as main windings and auxiliary.
• These two windings of the stator are connected at ninety angles to each other.
• This motor also has 2 capacitors which are connected in the circuit, capacitor (C_s) and the other is C_R both are connected in parallel with each other.

Permanent-Split Capacitor (PSC) Motor

• This type of induction motor has a cage rotor and its rotor comprises 2 windings first one is main and the other is auxiliary.

• This motor has one capacitor (C), it is linked with the starting winding in series.
• This capacitor © is enduringly associated in sequence with the starting winding.

 Shaded Pole Induction Motor

• This type of induction motor is a self-starting motor. It comprises a stator and a cage rotor.
• Its stating part is created by a salient pole. every pole is positioned on the side, and a copper ring is formfitting on the slighter portion.
• This portion is named the shaded pole.

Why a Single phase induction motor not self-starting?

• When the input voltage is provided at the stating part of the motor which creates fluctuating flux, this flux alternates about a particular axis.
• This flux does not produce the revolving magnetic field which causes to generate emf in the rotor. So that single-phase induction motor is not self-starting.
• To make the induction motor self-starting, it is temporarily transformed into a 2-phase motor when it started.

• For this process, the stator of a single-phase motor consists of one extra winding which is also known as starting winding.
• These two winding are positioned crossways the 1-phase supply.
• These two windings in stator are so arranged that the phase (ø) difference among the currents of two windings is very large. This phase difference converts this single-phase motor into two-phase motors.
• The 2 currents in two different windings produce a rotating magnetic field which makes a single-phase motor self-start motor.

Comparison between Single Phase and Three Phase Induction Motors

• Single-phase motors are modest in structure, consistent and inexpensive for trivial power rating as associated with three-phase induction motors.

1. The power factor of 1-ø induction motors is little as linked to 3 ø induction motors.
2. For similar dimensions, the single-ø induction motors make about fifty percent of the output as that of 3 ø induction motors.
3. The starting torque is also little for single ø induction motor.
4. The competence of single ø induction motors is less associated to that of 3 ø induction motors.

Advantages of single phase Induction Motor

• These are some advantages of a single-phase induction motor.
• The main benefit of the single-phase induction motor is that is assembly is very simple, it is easy to construct.
• The working of the induction motor is not depending on the environment disorder. Due to this, the motor is Vigorous and mechanically robust.
• An induction motor is an extremely well-organized appliance with full load competence changing from eighty-five to ninety-seven percent.

Applications of Single Phase Induction Motor

• These are some advantages of the single-phase induction motor that are described here.
  • The single phase motor is the main part of the different pumps used in our homes and industries.
  • Different compressors also used a single-phase induction motor.
  • The ceiling fans in our homes also consist of the single-phase motor.
  • Different juicer machines and blenders consist of single-phase induction motor
  • Different toys and robots also use induction motors for their movements.
  • Vacuum cleaners also consist of the induction motors.
  • Drilling machines are also used single-phase induction motor for their operation.

You can also read some related articles to the induction motor. That is described here.

• Introduction to Induction Motor
• Introduction to Three Phase Induction Motor
• Equivalent Circuit Induction Motor
• Induction Motor Torque-Speed Characteristics
• Variations in Induction Motor Torque-Speed Characteristics
• Power and Torque in Induction Motors
• Induction Motor Design Classes
• speed Control Method of Induction Motors
• Induction Motor Design
• No-load Test of Induction Motor
• Solid State Drive Induction Motor
• Derivation of the Induction Motor Induced-Torque Equation

So, friends, it is the detailed post on the single-phase induction motor, I have mentioned each and every component and related terms to the single-phase induction motor. If you have any query can ask in the comments. See you in the next tutorial, Derivation of the Induction Motor Induced-Torque Equation.