US 2003/0197581 A1 · Magnetic device for a magnetic trip unit

Abstract

A method and magnetic trip unit for actuating a latching mechanism to trip a circuit breaker upon an overcurrent condition, the magnetic trip unit including: a first electrically conductive strap configured to conduct an electrical current; a first magnet yoke disposed proximate to the first electrically conductive strap; and a first armature pivotally disposed proximate to the first magnetic yoke in operable communication with the latching mechanism; the first armature providing a magnetic path having a reluctance to magnetic flux; and the reluctance is adjusted to prevent saturation of the magnetic flux when the current through the strap is a first number times a rated current of the circuit breaker and the reluctance is adjusted to promote saturation of magnetic flux when the current through the strap is a second number times the rated current of the circuit breaker, wherein the first number is a number smaller than the second number.

Claims38

Dependent claims

A magnetic trip unit for actuating a latching mechanism to trip a circuit breaker upon an overcurrent condition, the magnetic trip unit including:

a first electrically conductive strap configured to conduct an electrical current;
a first magnet yoke disposed proximate to said first electrically conductive strap;
and
a first armature pivotally disposed proximate to said first magnetic yoke in operable communication with the latching mechanism;
said first armature providing a magnetic path having a reluctance to magnetic flux;
said reluctance is adjusted to prevent saturation of said magnetic flux when said current through said strap is a first number times a rated current of the circuit breaker and said reluctance is adjusted to promote saturation of said magnetic flux when said current through said strap is a second number times said rated current of the circuit breaker;
wherein said first number is a number smaller than said second number.

4 more elements

A circuit breaker including:

a first contact arm arranged between first and second electrically conductive straps;
a latching mechanism configured to move said first contact arm out of contact with said first and second electrically conductive straps;
a first magnet yoke disposed proximate to said first electrically conductive strap;
and
a first armature pivotally disposed proximate to said first magnetic yoke in operable communication with the latching mechanism;
said first armature providing a magnetic path having a reluctance to magnetic flux;
said reluctance is adjusted to prevent saturation of said magnetic flux when said current through said strap is a first number times a rated current of the circuit breaker and said reluctance is adjusted to promote saturation of said magnetic flux when said current through said strap is a second number times said rated current of the circuit breaker;
wherein said first number is a number smaller than said second number.

5 more elements

A method of increasing an induced magnetic force from a magnet yoke on a pivotally mounted armature of a trip unit in a circuit breaker at a low current without substantially altering the induced magnetic force acting on the armature at a high current, the method comprising:

configuring the armature to provide a magnetic path having a reluctance to a magnetic flux;
and
adjusting said reluctance of said magnetic path to prevent saturation of said magnetic flux when a current through the trip unit is a first number times a rated current of the circuit breaker, and said magnetic path is generally saturated when said current through the circuit breaker is a second number times said rated current, wherein said first number is a number smaller than said second number.

Dependencies are inferred from the claim text.

Magnetic device for a magnetic trip unit

Life of this patent

Magnetic device for a magnetic trip unit

Life of this patent

Abstract

Claims38