Bidirectional direct current electrical switching apparatus

A direct current electrical switching apparatus comprising:

• a first arc runner,
• a second arc runner;
• a third arc runner;
• a fourth arc runner;
• a first contact in electrical communication with said first and third arc runners;
• a second contact in electrical communication with said second and fourth arc runners;
• a movable contact comprising a first portion and a second portion respectively cooperating with said first contact and said second contact to provide a closed contact position in which said movable contact electrically engages said first and second contacts, and an open contact position in which said movable contact is disengaged from said first and second contacts;
• a first arc chamber comprising a first end, an opposite second end, a first longitudinal axis therebetween, and a plurality of first arc plates between the first end and the opposite second end, said first arc plates having a first width measured in a direction normal to said first longitudinal axis, one of the first arc plates at the first end of the first arc chamber being proximate said first arc runner, another one of the first arc plates at the opposite second end of the first arc chamber being proximate said second arc runner;
• a second arc chamber comprising a first end, an opposite second end, a second longitudinal axis therebetween, and a plurality of second arc plates between the first end and the opposite second end of the second arc chamber, said second arc plates having a second width measured in a direction normal to said second longitudinal axis, one of the second arc plates at the first end of the second arc chamber being proximate said third arc runner, another one of the second arc plates at the opposite second end of the second arc chamber being proximate said fourth arc runner;
• an operating mechanism cooperating with said movable contact to move said movable contact between the closed contact position and the open contact position;
• and
• a magnet assembly cooperating with said first and second arc chambers to establish generally oppositely directed magnetic fields normal to the first and second longitudinal axes, normal to a first direction of a first arc between said first contact and the first portion of said movable contact as said movable contact moves away from the closed contact position toward the open contact position, and normal to an opposite second direction of a second arc between said second contact and the second portion of said movable contact as said movable contact moves away from the closed contact position toward the open contact position, in order that said generally oppositely directed magnetic fields cause one of the first arc and the second arc to enter one of said first and second arc chambers, respectively, depending upon a direction of current flow between the first contact and the second contact,
• wherein said electrical switching apparatus is rated for a first magnitude of first current flowing from said first contact through said movable contact to said second contact and for a second magnitude of opposite second current flowing from said second contact through said movable contact to said first contact;
• wherein said second magnitude is greater than said first magnitude;
• and
• wherein said second width is greater than said first width.