What does cross field theory explain?

According to cross field theory, the stator flux can be resolved into two components which are mutually perpendicular. One acts along axis of the stator winding and other acts perpendicular to it. Due to the rotation, rotor physically cuts the stator flux and dynamically e.m.f. gets induced in the rotor.

What is cross field theory of single phase induction motor?

Consider a single phase induction motor with standstill rotor as shown in the Fig. Due to this flux, e.m.f., gets induced in the rotor conductors due to transformer action. As rotor is closed one, this e.m.f. circulates current through the rotor conductors.

What is cross field motor?

The cross-field theory of single phase induction motor helps to view the induction motor with a different point of view. This theory is related to the voltage and current which are static stator field can produce in the windings of the rotor when the rotor is rotating.

What is double field revolving theory?

The magnetic field produced by the stator winding when an alternating supply is given is equal to the sum of the two revolving fields rotating at synchronous speed in the opposite direction of equal magnitude.

Why single phase motors are not self-starting?

Single phase induction motor has distributed stator winding and a squirrel-cage rotor. When fed from a single-phase supply, its stator winding produces a flux ( or field ) which is only alternating i.e. one which alternates along one space axis only. That is why a single phase motor is not self-starting.

What is hysteresis motor?

The hysteresis motor is an alternating current motor of the rotating magnetic field type. A Hysteresis motor is a self-starting synchronous motor with a uniform air gap and without DC excitation that uses the hysteresis characteristics of magnetic materials to make torque.

Why single-phase motors are not self starting?

What causes slip in induction motor?

“Slip” in an AC induction motor is defined as: As the speed of the rotor drops below the stator speed, or synchronous speed, the rotation rate of the magnetic field in the rotor increases, inducing more current in the rotor’s windings and creating more torque.

What is a three phase induction motor and how does it work?

For induction motors, when the stator is powered from a three-phase electrical energy source, each coil generates a magnetic field whose poles (north or south) change position as the AC current oscillates through a complete cycle.

What is a double field?

Double Field is a small module written to provide extensions to Drupal’s core Fields. By this module you can split your fields up into two separate parts. For the moment it includes the following sub-field types: Boolean. Text.

What is the size of shaded pole motor in terms of HP?

Shaded-pole and reluctance motors are built in sizes from about 1/500 to 1/6 HP and can be made inexpensively but they have low starting torque, minimal overload capacity, and low efficiency.

Which type of motor is not self-starting?

single-phase induction motors
We can easily conclude that the single-phase induction motors are not self-starting because the produced stator flux is alternating in nature and at the starting, the two components of this flux cancel each other, and hence there is no net torque.

How is cross field theory used in single phase induction?

This can understand with the help of cross-field theory and double-revolving field theory. Consider standstill conditions with the stator winding connected to a single-phase AC supply. The stator current establishes a field that acts along the horizontal axis is shown in the below figure.

How is the direction of a cross field determined?

Due to the rotation, rotor physically cuts the stator flux and dynamically e.m.f. gets induced in the rotor. This is called speed e.m.f. or rotational e.m.f. The direction of such e.m.f. can be obtained by Flemung’s right hand rule and this e.m.f. in phase with the stator flux Φ s. The direction of e.m.f. is shown in the Fig. 2.

How is the rotor field related to the cross field?

The field produced by the rotor currents is at right angles to the field by the stator currents hence it is known as cross field. Thus the stator field Q s and rotor field Q r are in space and time quadrature.

How is speed induced in a cross field?

One acts along axis of the stator winding and other acts perpendicular to it. Assume now that an initial push is given to the rotor anticlockwise direction. Due to the rotation, rotor physically cuts the stator flux and dynamically e.m.f. gets induced in the rotor. This is called speed e.m.f. or rotational e.m.f.

What does cross field theory explain? According to cross field theory, the stator flux can be resolved into two components which are mutually perpendicular. One acts along axis of the stator winding and other acts perpendicular to it. Due to the rotation, rotor physically cuts the stator flux and dynamically e.m.f. gets induced in the…