Switching DC Circuits

Applications

Switching DC Circuits

An arc is a spark that occurs between the contacts when the switch turns OFF an electric circuit.
Arcing is more common at higher currents and lasts longer with slower contact switching speeds. If arcing lasts too long, contacts will wear drastically.

Switching DC Circuits

In AC circuits, where the direction of current flow changes, arcing is extinguished every time the voltage goes to 0 V.
With DC circuits, the current always flows in the same direction, which increases arcing time, causes contact wear, and reduces durability.
Contact transfer can also occur, causing rough contact surfaces which can catch and cause failure-to-open malfunctions.

In DC circuits, always use switches with DC ratings and use the switches so that the ratings are not exceeded.
There is also the X Series of Basic Switches for DC currents that provides a magnetic blowout mechanism.