FILTER OF ZERO-SEQUENCE CURRENT ON MAGNETIC REED SWITCHES FOR ELECTRIC INSTALLATION WITH HORIZONTAL CURRENT LEADS Russian patent published in 2009 - IPC H02H3/08 

FIELD: electricity.

SUBSTANCE: filter of zero-sequence current has the first and the second magnetic reed switches, logic part connected to contacts of the first magnetic reed switch, actuating device connected to output of logic part, as well as the first and the second additional windings wound on the first and the second magnetic reed switches respectively, control resistor connected to the first winding, amplifier connected to the second winding, phase-turning scheme the inputs of which are connected to outputs of amplifier, and the outputs of which are connected through control resistor to the first winding. At that, the first and the second magnetic reed switches are connected to the first and the second windings so that centre of gravity of the first one coincides with the point with coordinates h, γ₁=arctg(2h/(3d)) and x₁=d/2, and the second one - to the point with coordinates h, γ₂=-arctg(2h/(3d)), x₂=3d/2, where h - distance in vertical plane from horizontal line passing through centres of gravity of magnetic reed switches to current leads, γ₁ (γ₂) - angle between horizontal line and longitudinal axis of the first (second) magnetic reed switch, x₁ (x₂) - distance from centre of gravity of the first (second) magnetic reed switch to vertical line passing through centre of current lead of phase A, and d -distance between conductors of adjacent phases.

EFFECT: increasing filter sensitivity.

1 dwg