Bi-directional direct current switching apparatus having arc extinguishing chambers alternatively used according to polarity applied to said apparatus

Bi-directional direct current switching apparatus comprising:

• a spaced pair of arc extinguishing chambers;
• a third arc extinguishing chamber centrally disposed relative to said spaced pair of arc extinguishing chambers;
• a spaced pair of conductors connectable to a source of DC power, each conductor comprising a stationary contact and arc runner means leading from said contact to said third arc extinguishing chamber, said arc runner means being disposed between said spaced pair of arc extinguishing chambers;
• conductive means spaced from said stationary contacts and extending along said spaced pair of arc extinguishing chambers at sides of respective said chambers opposite said arc runner means, said conductive means and said arc runner means providing respective divergent guides from said stationary contacts to said divergent guides from said stationary contacts to said spaced pair of arc extinguishing chambers;
• a movable contact;
• drive means operable to move said movable contact into and out of bridging engagement with said stationary contacts;
• and
• means providing a magnetic field across said apparatus in a region comprising said stationary contacts and said arc extinguishing chambers, said magnetic field having a magnetic flux density directed substantially normal to movement of said movable contact, said magnetic field and electric current in arcs established between said movable and stationary contacts generating forces which assist movement of said arcs in predetermined directions away from said stationary contacts into said third arc extinguishing chamber or into said spaced pair of arc extinguishing chambers according to polarity of said spaced pair of conductors when connected to said source of DC power.