Patent ID: 6034858
Filing Date: 2000-03-07
Classification: G01R,H01F,H01H,H02H

Abstract:
A current transformer for monitoring a current level in a primary conductor and for providing a tripping signal to a relay in said primary conductor when an over current condition exists in said primary conductor, said current transformer comprising:a magnetic circuit for monitoring a magnitude of current flowing through a primary conductor, said magnetic circuit comprising a fixed element, a movable element, and air gaps located between said fixed element and said movable element, said movable element being movable towards said fixed element when an over current condition exists thereby reducing a size of said air gaps;biasing means for biasing said movable element to an open or closed position; anda secondary winding wound around at least a portion of said fixed element for providing a tripping signal to said relay to open said primary conductor;said elements arranged so that when said movable element moves towards said fixed element a large flux variation in said magnetic circuit is produced thereby inducing a current in said secondary winding.