All Sensata | Gigavac contactors can carry current in both directions on closed contacts.  The term “bidirectional” refers to the ability to switch/open while current is flowing.  Most Sensata | Gigavac contactors are designed and optimized to open current that is flowing in one direction to provide maximum current breaking capability.  We do have contactors that are designed to be bidirectional.  This is generally accomplished by changing the orientation of the internal arc blow-out magnets.  

The power terminals on polarized contactors are labeled positive (+) and negative (-).  This designation is intended to guide in the proper installation of the product.  Most contactors have internal arc blow-out magnets which are used for breaking loads (opening while current is flowing).  This is especially important for breaking loads of 48V and higher.  The blow-out magnets are designed for a specific direction of current flow.  Incorrect installation can limit or negate the benefit of the blow-out magnets and may decrease the life of the contactor significantly.  In applications where the system voltage exceeds 48V, care should be taken to install the contactors in the proper direction of current flow.  The contactor should be installed so that current flows into the positive (+) terminal and out of the negative (-) terminal.

If bidirectional contactors are used, the main power terminals can be connected in either direction.  The internal blowout magnets are configured to break the arc that forms regardless of which direction the current is flowing.