Design and method for keeping electrical contacts closed during short circuits

A method for maintaining a contact assembly in a closed position to allow a current flow through the contact assembly, and preventing the contact assembly from moving to an open position in which current flow is not allowed through the contact assembly, the method comprising the steps of:

• displacing a moveable conductor having a moveable contact and a moveable conducting surface, from the open position with the moveable contact spaced apart from a fixed contact to the closed position with the moveable contact contacting the fixed contact;
• flowing a current through the moveable conductor and through the fixed and moveable contacts;
• flowing the current through a fixed conductor having a fixed conducting surface proximate the moveable conducting surface when the contact assembly is in the closed position, the fixed conductor further comprising a first leg and a second leg disposed in a U-shape within a plane, and a tab extending from the fixed conductor in a direction away from the plane of the first and second legs;
• flowing the electric current through a braided wire connected to the tab and electrically connecting the moveable and fixed conductors;
• and
• flowing the current through the tab, whereby parasitic loss in the magnetic field of the moveable and fixed conducting surfaces due to a secondary magnetic field is reduced;
• the flowing current through the fixed and moveable conductors generating electromagnetic forces between the fixed and moveable conductors, resisting movement of the moveable contact toward the open position;
• and
• the flowing current through the fixed and moveable conductors creating a magnetic field in a magnetic yoke in proximity to the fixed and moveable conductors, the magnetic field causing the yoke to exert a magnetic force on a magnetic armature fixed to the moveable conductor, thereby further resisting movement of the moveable contact toward the open position.

A circuit breaker assembly positionable in a circuit between a line and a load, the assembly comprising:

• a circuit breaker set to open the circuit between the line and the load at or above a predetermined current load;
• and
• a contact assembly in series with the circuit breaker and adapted to remotely open and close the circuit between the line and the load, the contact assembly having a closed position to allow current flow through the contact assembly and an open position to prevent current flow through the contact assembly, the contact assembly comprising:
• a moveable conductor having a moveable contact and a moveable conducting surface;
• a fixed contact;
• the moveable conductor being moveable between the closed position with the moveable contact contacting the fixed contact, and the open position with the moveable contact spaced apart from the fixed contact;
• a fixed conductor defining a U-shaped conducting path having a fixed conducting surface proximate the moveable conducting surface when the contact assembly is in the closed position, the U-shaped conducting path defining a slot;
• the moveable and fixed conductors being electrically connected to conduct the current flow through the conductors in directions such that electromagnetic forces generated thereby resist movement of the moveable contact toward the open position;
• a magnetic armature fixed to the moveable conductor;
• a magnetic yoke disposed in the slot defined by the U-shaped conducting path of the fixed conductor, whereby current through the fixed conductor and current through the moveable conductor both cause the yoke to exert a magnetic force on the armature, and thereby resist movement of the moveable contact toward the open position;
• and
• a braided wire electrically connecting the moveable and fixed conductors;
• wherein the fixed conductor further comprises a first leg and a second leg disposed in a U-shape within a plane, and a tab extending from the fixed conductor in a direction away from the plane of the first and second legs, the braided wire being connected to the tab, whereby parasitic loss in the magnetic field of the moveable and fixed conducting surfaces due to a secondary magnetic field is reduced.

A contact assembly having a closed position to allow current flow through the contact assembly and an open position to prevent current flow through the contact assembly, the assembly comprising:

• a moveable conductor including a moveable contact;
• a fixed contact;
• the moveable conductor being moveable between the closed position with the moveable contact contacting the fixed contact, and the open position with the moveable contact spaced apart from the fixed contact;
• a spring biasing the moveable contact toward the fixed contact, to thereby resist movement of the moveable contact toward the open position;
• a fixed conductor, the moveable and fixed conductors being electrically connected in series to conduct the current through the conductors;
• a magnetic armature fixed to the moveable conductor;
• a magnetic yoke proximate the fixed conductor and proximate the moving conductor, whereby current through each of the fixed conductor and the moveable conductor induces a magnetic field in the yoke to attract the armature, and thereby resists movement of the moveable contact toward the open position;
• and
• a braided wire electrically connecting the moveable and fixed conductors;
• wherein the fixed conductor further comprises a first leg and a second leg disposed in a U-shape within a plane, and a tab extending from the fixed conductor in a direction away from the plane of the first and second legs, the braided wire being connected to the tab, whereby parasitic loss in the magnetic field of the moveable and fixed conducting surfaces due to a secondary magnetic field is reduced.