Apparatus and method for safe state retention

摘要

A transformer core apparatus includes a body of highly magnetically permeable material, a permanent magnet arranged in a safe state position for saturating the body with a permanent magnetic field, and means for removing the permanent magnetic field from the body.

主权项

1. A power supply apparatus comprising:
a transformer core; a primary winding arranged to supply, while energized, a varying primary magnetic field for exciting the transformer core; a secondary winding electrically isolated from the primary winding and arranged to be energized by the varying primary magnetic field in the transformer core; a permanent magnet arranged in a first position to prevent excitation of the transformer core by saturating the transformer core with a permanent magnetic field; and a bias winding connected to receive current from the secondary winding and arranged to supply, while energized, a bias magnetic field for preventing saturation of the transformer core by the permanent magnetic field; wherein discontinuation of current from the secondary winding to the bias winding will cause restoration of the permanent magnetic field to saturate the transformer core.