Windings & Magnetic Fields

Description: The stator of a 3-phase (2-pole) AC machine may be represented by 3 sinusoidally distributed windings [RGB] whose axes are displaced by 120°. When the windings are excited with balanced 3-phase sinusoidal currents, each phase produces a pulsating sinusoidal field described by a space vector directed along the winding axis and pointing to where the field is maximum positive. The combined effect is equivalent to having a single sinusoidally distributed winding which is excited with a constant current and rotates at the excitation frequency. The motion of the associated space vectors is illustrated.

Description: A sinusoidally distributed winding is excited with a sinusoidal current. The resulting pulsating radial flux density distribution is shown plotted along a circular path in the air gap (which is greatly enlarged for visual purposes). A 2-pole and 4-pole configurations are illustrated. In the 2-pole view, the spatial sinusoidal field distribution can be represented by a 2D space vector located along the (horizontal) axis of the winding; the vector points to where the field is maximum positive and has a length proportional to the maximum field strength at that instant. Both cross-sectional and developed views of the distributions are presented.

Description: A rotating sinusoidally distributed winding is excited with a constant current. The flux plot in the air gap also rotates. Where the lines are crowded, the corresponding magnetic field density B is high, and where the concentration of lines is reduced so is B. Thus the air gap B-field is sinusoidally distributed in space and is also rotating. It can be represented by a rotating space vector of constant magnitude pointing to where the field is maximum positive.

Description: Under balanced 3-phase sinusoidal excitation of an ac machine, the field space distribution produced by each phase is a sinusoidally distributed pulsating wave centered in its axis. The ABC [ R G B ] axes are 120° apart. The resultant field (in black) is a traveling wave of constant amplitude moving at a speed which corresponds to the excitation frequency.

Description: The stator of a 3-phase (2-pole) AC machine may be represented by 3 sinusoidally distributed windings [ R G B ] whose axes are displaced by 120°. When the windings are excited with balanced 3-phase sinusoidal currents, the combined effect is equivalent to having a single sinusoidally distributed winding excited with a constant current and rotating at the stator frequency. The pulsating space vectors associated with the ABC windings and the resulting rotating space vector R are shown in motion.

Description: Explore concentrated stator winding.

Description: Explore distributed winding.

Description: Explore 1-phase sinusoidal windings (static).

Description: Explore 3-phase stator windings.

Description: Explore armature mmf waves: sinusoidal windings.

Description: Explore sinusoidal windings 2.

Description: Explore flux plots and b-field distributions.

Description: Explore induction machine: field space distribution.

Description: Explore mmf space distributions in a three-phase ac machine.

Description: Explore forces and fields in a current-carrying conductor.

Description: Reference diagrams for flux plot in a c-core magnetic structure.