Hi, reader welcomes to the new post. In this tutorial, we will discuss the Cross-Field Theory of Single-Phase Induction Motors. The induction motor belongs to the ac family of motors. There are two main types of induction motors single-phase and three-phase induction motors. single motor called single phase motor since it operates on single-phase and a three-phase induction motor operates on 3 phases.
In this post, we will cover details about the cross-field theory of single-phase induction motors and its related parameters. So let’s get started with cross field theory
Cross-Field Theory of Single-Phase Induction Motors
- Cross field theory of single-phase induction motor is explained here
- The cross-field theory of single phase induction motor helps to view the induction motor from a different point of view.
- This theory is related to the voltage and current which are static stator fields that can be produced in the windings of the rotor when the rotor is rotating.
- Let us assume that a single-phase induction motor has a rotor that is taken to speed through the use of any exterior technique.
- This type of motor can see here.
- Voltage is produced in the rotors through the peak voltage existing in the windings moving directly through the windings existing in the stator.
- This rotor voltage generates a current in the rotor but the sine of the high value of reactance of the rotor, the current lags the voltage through the angle of ninety degrees.
- The rotor rotating speed is almost equal to the synchronous speed so ninety ninety-degree lagging factor in current generates the ninety degrees angular shift among the plane of peak rotor voltage and the plane of peak current.
- In the below figure you can see the resultant rotor field.
- The rotor field is less than the stator field, since the loss of the rotor but there is a difference of ninety degrees angle in space and time as well.
- If these 2 fields are added for different time intervals so we can see that the net field in the motor is revolving in the anticlockwise direction.
- Through the rotating field existing in the motor induction motor will create the total torque in the direction of movement and that torque will retain the rotor moving.
- If the rotor of the motor is moving in a clockwise direction the net torque will have a clockwise direction and will again retain the motor moving.
Cross Field theory of Induction motor
The cross-field theory defines the differnt parameters of single-phase induction motors that are
- Starting: At the start of the motor rotor is in static condition and the rotor flux is zero. The start flcu produced the voltage in the rotor and the current rotor is very less due to the high resistance provided by the rotor. Due to this small current flux of less strength is generated in a perpendicular direction to the stator flux. So torque generated by the motor is small. As the motor moves rotor flux increases and is configured with stator flux. That generated torque for the motor to continue rotation at normal speed
- Running: The roto flux is at ninety degrees out of phase with stator flux at running speed conditions. That results in the highest torque that helps the motor rotate at a constant speed.
- Slipping: With the increment of load motor speed decreases. It will affect the alignment of the rotor flux with the station flux to minimize the torque. the speed of to continuously decreases and torque becomes equal to load.
Faqs.
What is a cross field motor?
A cross-field motor is a type that generates the torque with the use of two magnetic fields configured at ninety degrees to each other. These motors are used in low-power projects and applications like blowers and fans
What are the theories used in single phase induction motor?
cross-field theory and the double-revolving field theory are used to explain the working single-phase induction motor. The cross-field theory is a simple theory but the double-revolving field theory provides the accurate results
What is single-phase induction motor also known as?
Single-phase induction motors also called split-phase motors, are capacitor-start motors. and shaded-pole motors
That is a detailed post about the cross-field theory of induction motors. If you have any further queries ask in the comments. Thanks for reading. Have a nice day