The spatial distribution of flux waveform across the limbs in a three-phase transformer core

A scale model of three-phase three-limbed transformer cores, in which the magnetic path length varied significantly within the width of the limbs, was instrumented to observe the flux distribution in the laminations. Across the width of the center limb the local field was found to decrease monotonically with distance from the window and was minimum at the middle of the limb. In the outside limbs the local field was maximum near the window and gradually decreased across the width. The harmonic components varied in a similar fashion, although those in the center limb were 65 percent higher than those in the outside limbs. The experimental results confirmed that the magnetic material locally traverses a characteristic hysteresis loop.